Date   

Re: Band II antenna

Simon Brown
 

Ah,

I buy direct, maybe that helped.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 10 July 2022 08:31
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] Band II antenna
 

OK I will try him again, he passed it on to Wimo who failed miserably.

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 10 July 2022 09:30
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Band II antenna

 

Hi,

 

The 8 element innov is very good, it's worth waiting for. Send Justin a direct mail if you have problems.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 10 July 2022 08:26
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Cc: Rob Hardenberg <rob@...>
Subject: [SDR-Radio] Band II antenna

 

As there are more experienced Band II DXers lurking can you recommend a Band II antenna? Max boom-length 5m and in stock somewhere in Europe. I ordered an Innovantennas OPT-DES which has not showed up 16 weeks later, so I cancelled the order. I have a crappy 3 ele up now. It was good enough for MUF tracking but would like something better for tropo.

 

Any recommendations?

 

Regards

 

Conrad PA5Y


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Re: SDRC and Airspy R2

jdow
 

A good 3 dB splitter is 3 dB. Four way is 6 dB. etc. If you play with resistors only then you get nastier losses - and no ferrite overload issues. It's a tradeoff.

{^_^}

On 20220710 00:12:46, Conrad, PA5Y wrote:

I do not agree entirely.

 

A 4-way resistive splitter has 12dB of loss, the resulting 5.75dB noise figure which is not good enough. If you used a narrow band 4 way hybrid splitter, then that would result in a good enough system NF,  but also expensive. You are absolutely right about AGC in conventional receivers. Not sure how it works with SDRs. I always run LNAs at max gain and attenuate the output as required.

 

The only point I was trying to make is that it is best to analyse the system noise temp and not just slap things together willy nilly.

 

Regards

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 10 July 2022 09:00
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

If he runs the PA at full steam (which is likely to also give the best dynamic range) there is a serious LOT of room for splitters. An 8 way splitter would work adequately. That's 9 dB so there is a room for a 2 dB to 4 dBpad on each output so that you have slightly better isolation. For 4 way split you'd use higher attenuation.

Erm,. I remember the day I decided to look into what happened with AGC circuits on analog circuitry. Every one of them I looked at gave dynamic range issues when the AGC was providing a lot of attenuation. I overdosed on Taylor series expansions. That was one of the worst aw s*t moments of my life - in the same league as when I figured out I could not live with my ex anymore. We were too different. (And now I've figured out that a lot of it is me as an aspergers trying to live with a neuro-typical who totally misunderstood me.)

{^_^}   (Undecided with regards to using diodes as attenuators which was not a thing back then.)

On 20220709 14:49:06, Conrad, PA5Y wrote:

If you do add a splitter it is best to do a system noise analysis; there would be very little point in having a 4 way resistive splitter with a 9dB RX NF connected to it using the LNA example I gave.  Its not difficult to calculate and AppCAD is free. The idea of the attenuator is to set the optimum gain for the conditions/ required sensitivity.

 

It is not totally optimal in terms of SFDR, but it is flexible, and you won’t be far off.

 

Regards

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Siegfried Jackstien via groups.io
Sent: 09 July 2022 22:10
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

that 18 db gain may make a bit deaf receive shine :-) 

or dig out that rare dx signal

or give you enough oumph on the cable to use passive splitters for a handful of receivers without worry about losses (last would be my thinking)

if you only want to do fm dxing then an added filter may help to clean up the receive a bit (and also such a filter plus cabling adds loss)

 

just thinking ;-)

 

dg9bfc sigi

 

Am 09.07.2022 um 20:42 schrieb jdow:

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


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Re: Band II antenna

Conrad, PA5Y
 

OK I will try him again, he passed it on to Wimo who failed miserably.

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 10 July 2022 09:30
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Band II antenna

 

Hi,

 

The 8 element innov is very good, it's worth waiting for. Send Justin a direct mail if you have problems.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 10 July 2022 08:26
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Cc: Rob Hardenberg <rob@...>
Subject: [SDR-Radio] Band II antenna

 

As there are more experienced Band II DXers lurking can you recommend a Band II antenna? Max boom-length 5m and in stock somewhere in Europe. I ordered an Innovantennas OPT-DES which has not showed up 16 weeks later, so I cancelled the order. I have a crappy 3 ele up now. It was good enough for MUF tracking but would like something better for tropo.

 

Any recommendations?

 

Regards

 

Conrad PA5Y


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- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


Re: Band II antenna

Simon Brown
 

Hi,

The 8 element innov is very good, it's worth waiting for. Send Justin a direct mail if you have problems.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 10 July 2022 08:26
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Cc: Rob Hardenberg <rob@...>
Subject: [SDR-Radio] Band II antenna
 

As there are more experienced Band II DXers lurking can you recommend a Band II antenna? Max boom-length 5m and in stock somewhere in Europe. I ordered an Innovantennas OPT-DES which has not showed up 16 weeks later, so I cancelled the order. I have a crappy 3 ele up now. It was good enough for MUF tracking but would like something better for tropo.

 

Any recommendations?

 

Regards

 

Conrad PA5Y


--
- + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


Band II antenna

Conrad, PA5Y
 

As there are more experienced Band II DXers lurking can you recommend a Band II antenna? Max boom-length 5m and in stock somewhere in Europe. I ordered an Innovantennas OPT-DES which has not showed up 16 weeks later, so I cancelled the order. I have a crappy 3 ele up now. It was good enough for MUF tracking but would like something better for tropo.

 

Any recommendations?

 

Regards

 

Conrad PA5Y


Re: SDRC and Airspy R2

Conrad, PA5Y
 

I do not agree entirely.

 

A 4-way resistive splitter has 12dB of loss, the resulting 5.75dB noise figure which is not good enough. If you used a narrow band 4 way hybrid splitter, then that would result in a good enough system NF,  but also expensive. You are absolutely right about AGC in conventional receivers. Not sure how it works with SDRs. I always run LNAs at max gain and attenuate the output as required.

 

The only point I was trying to make is that it is best to analyse the system noise temp and not just slap things together willy nilly.

 

Regards

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 10 July 2022 09:00
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

If he runs the PA at full steam (which is likely to also give the best dynamic range) there is a serious LOT of room for splitters. An 8 way splitter would work adequately. That's 9 dB so there is a room for a 2 dB to 4 dBpad on each output so that you have slightly better isolation. For 4 way split you'd use higher attenuation.

Erm,. I remember the day I decided to look into what happened with AGC circuits on analog circuitry. Every one of them I looked at gave dynamic range issues when the AGC was providing a lot of attenuation. I overdosed on Taylor series expansions. That was one of the worst aw s*t moments of my life - in the same league as when I figured out I could not live with my ex anymore. We were too different. (And now I've figured out that a lot of it is me as an aspergers trying to live with a neuro-typical who totally misunderstood me.)

{^_^}   (Undecided with regards to using diodes as attenuators which was not a thing back then.)

On 20220709 14:49:06, Conrad, PA5Y wrote:

If you do add a splitter it is best to do a system noise analysis; there would be very little point in having a 4 way resistive splitter with a 9dB RX NF connected to it using the LNA example I gave.  Its not difficult to calculate and AppCAD is free. The idea of the attenuator is to set the optimum gain for the conditions/ required sensitivity.

 

It is not totally optimal in terms of SFDR, but it is flexible, and you won’t be far off.

 

Regards

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Siegfried Jackstien via groups.io
Sent: 09 July 2022 22:10
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

that 18 db gain may make a bit deaf receive shine :-) 

or dig out that rare dx signal

or give you enough oumph on the cable to use passive splitters for a handful of receivers without worry about losses (last would be my thinking)

if you only want to do fm dxing then an added filter may help to clean up the receive a bit (and also such a filter plus cabling adds loss)

 

just thinking ;-)

 

dg9bfc sigi

 

Am 09.07.2022 um 20:42 schrieb jdow:

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


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Re: SDRC and Airspy R2

jdow
 

That is the best policy. However, I have violated it in the past. Since I don't have to be manly I've been content at 100W generally.

{^_^}

On 20220710 00:02:23, Conrad, PA5Y wrote:

Hi Simon, I use a cheap VNA to measure the coupling between antennas. The 80m dipole most likely won’t matter but 2m will. I bypass my Band II LNA when I TX on any band, in fact I bypass all LNAs when I TX on any band, therefore I use energised relays on RX. Some effort required but it is Conrad proof!

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 10 July 2022 08:56
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The preamp's BPF is important, I wonder how much input signal it can handle as my 80m dipole is ~30cms below the Band II Yagi and I have a 2m antenna ~4m away and I run full legal on all bands when the mood takes me.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 10 July 2022 07:50
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

It should be possible, just about. From the S3 user manual.

 

The FDM-S3 has two antenna biases, one for the HF-2 input and one for the VHF input. The supplied voltage is 5V (max 150mA).

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 10 July 2022 08:46
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

5V at a whomping 150 mA. That latter may be the show stopper if you try to use your front end's Bias-T.

And why that version and not "https://www.tgn-technology-online.com/en/Low-Noise-Amplifier-ULNA3018.html"? The "Specifications" suggest it has the power supply. The "Accessories" suggests not. The pictures suggest it does have the PS. Ah, I see, it lacks the bias-T for its PS. If you determine your front end's bias-t can handle the load they all seem to be the same amplifier so the cheapest one should be good enough.

{^_^}

On 20220709 12:21:49, Conrad, PA5Y wrote:

Ah this one does need 5V, there you are then.

 

https://www.tgn-technology-online.com/en/Low-Noise-FM-Amplifier-ULNA3018.html

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:19
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The active device in the TGN amplifiers will not actually need 10V, as you have a bias T in the S3 you should ask TGN if they can use a different regulator in the LNA so that you can use 5V. There are cheaper alternatives.

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:09
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Here is a rough and ready analysis with a 6dB attenuator, this would typically be a 10dB step attenuator, set according to conditions.

 

It gives 84dB SFDR based on the S3 user guide and the PGA103+ datasheet. The first 2 stages are typical of a band II amplifier with front end selectivity.

 

Anyway, this gives you an idea.

 

Conrad

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 21:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.

 

I have 25m RG6.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 19:52
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

I could not agree more, a step attenuator on the output is a good idea. You can of course use the noise free bias tee on the S3 for the supply. These are almost certainly PGA103+ LNAs.  You can use AppCAD and do a system noise analysis. If you like I will do one and put it on here. In fact I may have already done one and posted it some time ago. I’ll have a look.

 

Conrad

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 09 July 2022 20:42
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


Re: SDRC and Airspy R2

jdow
 

It should be possible to find an old TVI filter and put that in front of the LNA. There'd be a few tenths of a dB hit on noise figure, typically.


{^_^}

On 20220709 23:55:33, Simon Brown wrote:

The preamp's BPF is important, I wonder how much input signal it can handle as my 80m dipole is ~30cms below the Band II Yagi and I have a 2m antenna ~4m away and I run full legal on all bands when the mood takes me.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 10 July 2022 07:50
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2
 

It should be possible, just about. From the S3 user manual.

 

The FDM-S3 has two antenna biases, one for the HF-2 input and one for the VHF input. The supplied voltage is 5V (max 150mA).

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 10 July 2022 08:46
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

5V at a whomping 150 mA. That latter may be the show stopper if you try to use your front end's Bias-T.

And why that version and not "https://www.tgn-technology-online.com/en/Low-Noise-Amplifier-ULNA3018.html"? The "Specifications" suggest it has the power supply. The "Accessories" suggests not. The pictures suggest it does have the PS. Ah, I see, it lacks the bias-T for its PS. If you determine your front end's bias-t can handle the load they all seem to be the same amplifier so the cheapest one should be good enough.

{^_^}

On 20220709 12:21:49, Conrad, PA5Y wrote:

Ah this one does need 5V, there you are then.

 

https://www.tgn-technology-online.com/en/Low-Noise-FM-Amplifier-ULNA3018.html

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:19
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The active device in the TGN amplifiers will not actually need 10V, as you have a bias T in the S3 you should ask TGN if they can use a different regulator in the LNA so that you can use 5V. There are cheaper alternatives.

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:09
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Here is a rough and ready analysis with a 6dB attenuator, this would typically be a 10dB step attenuator, set according to conditions.

 

It gives 84dB SFDR based on the S3 user guide and the PGA103+ datasheet. The first 2 stages are typical of a band II amplifier with front end selectivity.

 

Anyway, this gives you an idea.

 

Conrad

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 21:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.

 

I have 25m RG6.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 19:52
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

I could not agree more, a step attenuator on the output is a good idea. You can of course use the noise free bias tee on the S3 for the supply. These are almost certainly PGA103+ LNAs.  You can use AppCAD and do a system noise analysis. If you like I will do one and put it on here. In fact I may have already done one and posted it some time ago. I’ll have a look.

 

Conrad

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 09 July 2022 20:42
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--
- + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


Re: SDRC and Airspy R2

jdow
 

On the most expensive unit the "Pro" model a remark seemed to indicate that it's gain was dependent on PS voltage 10V to 18V. BUT - that page is a mess of cut and paste. I don't know what you really get with any of the packages. The specifications seem quite incomplete.

{^_^}

On 20220709 23:34:50, Conrad, PA5Y wrote:

Does it? I don’t like that idea at all. The specifications say 5V at 150mA.

 

Conrad

  • Frequency 88-108 MHz
  • Gain 10-18 dB variabel
  • Noise figure 0,30 dB
  • 3dB BW typ MHz 70 MHz
  • Max. Outputlevel 119dB/µV
  • Input Return loss min -12dB
  • Output Return loss min -16dB
  • Sttenuation
    • FM   -28dB
    • UHF -45dB
  • Connectors F-F Male
  • DC supply 5V@150mA
  • DC supply via Coaxcabel 5V@150mA
  • Dimensions 99X39X40 mm

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 10 July 2022 08:32
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

It appears they require their own power supply with the gain being controlled by the supply voltage.

 

{^_^}

On 20220709 12:01:14, Simon Brown wrote:

Hi,

 

Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.

 

I have 25m RG6.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 19:52
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

I could not agree more, a step attenuator on the output is a good idea. You can of course use the noise free bias tee on the S3 for the supply. These are almost certainly PGA103+ LNAs.  You can use AppCAD and do a system noise analysis. If you like I will do one and put it on here. In fact I may have already done one and posted it some time ago. I’ll have a look.

 

Conrad

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 09 July 2022 20:42
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


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Re: SDRC and Airspy R2

Conrad, PA5Y
 

Hi Simon, I use a cheap VNA to measure the coupling between antennas. The 80m dipole most likely won’t matter but 2m will. I bypass my Band II LNA when I TX on any band, in fact I bypass all LNAs when I TX on any band, therefore I use energised relays on RX. Some effort required but it is Conrad proof!

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 10 July 2022 08:56
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The preamp's BPF is important, I wonder how much input signal it can handle as my 80m dipole is ~30cms below the Band II Yagi and I have a 2m antenna ~4m away and I run full legal on all bands when the mood takes me.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 10 July 2022 07:50
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

It should be possible, just about. From the S3 user manual.

 

The FDM-S3 has two antenna biases, one for the HF-2 input and one for the VHF input. The supplied voltage is 5V (max 150mA).

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 10 July 2022 08:46
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

5V at a whomping 150 mA. That latter may be the show stopper if you try to use your front end's Bias-T.

And why that version and not "https://www.tgn-technology-online.com/en/Low-Noise-Amplifier-ULNA3018.html"? The "Specifications" suggest it has the power supply. The "Accessories" suggests not. The pictures suggest it does have the PS. Ah, I see, it lacks the bias-T for its PS. If you determine your front end's bias-t can handle the load they all seem to be the same amplifier so the cheapest one should be good enough.

{^_^}

On 20220709 12:21:49, Conrad, PA5Y wrote:

Ah this one does need 5V, there you are then.

 

https://www.tgn-technology-online.com/en/Low-Noise-FM-Amplifier-ULNA3018.html

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:19
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The active device in the TGN amplifiers will not actually need 10V, as you have a bias T in the S3 you should ask TGN if they can use a different regulator in the LNA so that you can use 5V. There are cheaper alternatives.

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:09
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Here is a rough and ready analysis with a 6dB attenuator, this would typically be a 10dB step attenuator, set according to conditions.

 

It gives 84dB SFDR based on the S3 user guide and the PGA103+ datasheet. The first 2 stages are typical of a band II amplifier with front end selectivity.

 

Anyway, this gives you an idea.

 

Conrad

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 21:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.

 

I have 25m RG6.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 19:52
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

I could not agree more, a step attenuator on the output is a good idea. You can of course use the noise free bias tee on the S3 for the supply. These are almost certainly PGA103+ LNAs.  You can use AppCAD and do a system noise analysis. If you like I will do one and put it on here. In fact I may have already done one and posted it some time ago. I’ll have a look.

 

Conrad

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 09 July 2022 20:42
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


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--

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Re: SDRC and Airspy R2

jdow
 

Check out the analysis Conrad posted.

{^_-}

On 20220709 14:57:45, Siegfried Jackstien wrote:

antenna ...lna .....cable to shack.....splitter ... (and a handfull of receivers)

the noise figure comes from the front lna ... not?!?

other things to consider is overload of the lna if you have strong signals close to your station (even if outside of the fm band)

whatever it may be ... a radio station, cell tower, airport, ham operator?? in that case a filter between antenna and lna does do wonders :-) and if that setup is only used for fm dxing a bandpass 88 to 108 is a good thing to add

dg9bfc

Am 09.07.2022 um 23:49 schrieb Conrad, PA5Y:

If you do add a splitter it is best to do a system noise analysis; there would be very little point in having a 4 way resistive splitter with a 9dB RX NF connected to it using the LNA example I gave.  Its not difficult to calculate and AppCAD is free. The idea of the attenuator is to set the optimum gain for the conditions/ required sensitivity.

 

It is not totally optimal in terms of SFDR, but it is flexible, and you won’t be far off.

 

Regards

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Siegfried Jackstien via groups.io
Sent: 09 July 2022 22:10
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

that 18 db gain may make a bit deaf receive shine :-) 

or dig out that rare dx signal

or give you enough oumph on the cable to use passive splitters for a handful of receivers without worry about losses (last would be my thinking)

if you only want to do fm dxing then an added filter may help to clean up the receive a bit (and also such a filter plus cabling adds loss)

 

just thinking ;-)

 

dg9bfc sigi

 

Am 09.07.2022 um 20:42 schrieb jdow:

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


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Re: SDRC and Airspy R2

jdow
 

If he runs the PA at full steam (which is likely to also give the best dynamic range) there is a serious LOT of room for splitters. An 8 way splitter would work adequately. That's 9 dB so there is a room for a 2 dB to 4 dBpad on each output so that you have slightly better isolation. For 4 way split you'd use higher attenuation.

Erm,. I remember the day I decided to look into what happened with AGC circuits on analog circuitry. Every one of them I looked at gave dynamic range issues when the AGC was providing a lot of attenuation. I overdosed on Taylor series expansions. That was one of the worst aw s*t moments of my life - in the same league as when I figured out I could not live with my ex anymore. We were too different. (And now I've figured out that a lot of it is me as an aspergers trying to live with a neuro-typical who totally misunderstood me.)

{^_^}   (Undecided with regards to using diodes as attenuators which was not a thing back then.)

On 20220709 14:49:06, Conrad, PA5Y wrote:

If you do add a splitter it is best to do a system noise analysis; there would be very little point in having a 4 way resistive splitter with a 9dB RX NF connected to it using the LNA example I gave.  Its not difficult to calculate and AppCAD is free. The idea of the attenuator is to set the optimum gain for the conditions/ required sensitivity.

 

It is not totally optimal in terms of SFDR, but it is flexible, and you won’t be far off.

 

Regards

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Siegfried Jackstien via groups.io
Sent: 09 July 2022 22:10
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

that 18 db gain may make a bit deaf receive shine :-) 

or dig out that rare dx signal

or give you enough oumph on the cable to use passive splitters for a handful of receivers without worry about losses (last would be my thinking)

if you only want to do fm dxing then an added filter may help to clean up the receive a bit (and also such a filter plus cabling adds loss)

 

just thinking ;-)

 

dg9bfc sigi

 

Am 09.07.2022 um 20:42 schrieb jdow:

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


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Re: SDRC and Airspy R2

Simon Brown
 

The preamp's BPF is important, I wonder how much input signal it can handle as my 80m dipole is ~30cms below the Band II Yagi and I have a 2m antenna ~4m away and I run full legal on all bands when the mood takes me.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 10 July 2022 07:50
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2
 

It should be possible, just about. From the S3 user manual.

 

The FDM-S3 has two antenna biases, one for the HF-2 input and one for the VHF input. The supplied voltage is 5V (max 150mA).

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 10 July 2022 08:46
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

5V at a whomping 150 mA. That latter may be the show stopper if you try to use your front end's Bias-T.

And why that version and not "https://www.tgn-technology-online.com/en/Low-Noise-Amplifier-ULNA3018.html"? The "Specifications" suggest it has the power supply. The "Accessories" suggests not. The pictures suggest it does have the PS. Ah, I see, it lacks the bias-T for its PS. If you determine your front end's bias-t can handle the load they all seem to be the same amplifier so the cheapest one should be good enough.

{^_^}

On 20220709 12:21:49, Conrad, PA5Y wrote:

Ah this one does need 5V, there you are then.

 

https://www.tgn-technology-online.com/en/Low-Noise-FM-Amplifier-ULNA3018.html

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:19
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The active device in the TGN amplifiers will not actually need 10V, as you have a bias T in the S3 you should ask TGN if they can use a different regulator in the LNA so that you can use 5V. There are cheaper alternatives.

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:09
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Here is a rough and ready analysis with a 6dB attenuator, this would typically be a 10dB step attenuator, set according to conditions.

 

It gives 84dB SFDR based on the S3 user guide and the PGA103+ datasheet. The first 2 stages are typical of a band II amplifier with front end selectivity.

 

Anyway, this gives you an idea.

 

Conrad

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 21:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.

 

I have 25m RG6.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 19:52
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

I could not agree more, a step attenuator on the output is a good idea. You can of course use the noise free bias tee on the S3 for the supply. These are almost certainly PGA103+ LNAs.  You can use AppCAD and do a system noise analysis. If you like I will do one and put it on here. In fact I may have already done one and posted it some time ago. I’ll have a look.

 

Conrad

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 09 July 2022 20:42
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


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--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

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Re: SDRC and Airspy R2

Conrad, PA5Y
 

It should be possible, just about. From the S3 user manual.

 

The FDM-S3 has two antenna biases, one for the HF-2 input and one for the VHF input. The supplied voltage is 5V (max 150mA).

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 10 July 2022 08:46
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

5V at a whomping 150 mA. That latter may be the show stopper if you try to use your front end's Bias-T.

And why that version and not "https://www.tgn-technology-online.com/en/Low-Noise-Amplifier-ULNA3018.html"? The "Specifications" suggest it has the power supply. The "Accessories" suggests not. The pictures suggest it does have the PS. Ah, I see, it lacks the bias-T for its PS. If you determine your front end's bias-t can handle the load they all seem to be the same amplifier so the cheapest one should be good enough.

{^_^}

On 20220709 12:21:49, Conrad, PA5Y wrote:

Ah this one does need 5V, there you are then.

 

https://www.tgn-technology-online.com/en/Low-Noise-FM-Amplifier-ULNA3018.html

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:19
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The active device in the TGN amplifiers will not actually need 10V, as you have a bias T in the S3 you should ask TGN if they can use a different regulator in the LNA so that you can use 5V. There are cheaper alternatives.

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:09
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Here is a rough and ready analysis with a 6dB attenuator, this would typically be a 10dB step attenuator, set according to conditions.

 

It gives 84dB SFDR based on the S3 user guide and the PGA103+ datasheet. The first 2 stages are typical of a band II amplifier with front end selectivity.

 

Anyway, this gives you an idea.

 

Conrad

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 21:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.

 

I have 25m RG6.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 19:52
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

I could not agree more, a step attenuator on the output is a good idea. You can of course use the noise free bias tee on the S3 for the supply. These are almost certainly PGA103+ LNAs.  You can use AppCAD and do a system noise analysis. If you like I will do one and put it on here. In fact I may have already done one and posted it some time ago. I’ll have a look.

 

Conrad

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 09 July 2022 20:42
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

- + - + -

Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


--

- + - + -

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Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


Re: Mystery mode

jdow
 

Duration, frequency spacing, and any modulation (probably PM of some sort) would be interesting. Post processing to pull out relative timing and the like can also possibly pull out modulation using wide band USB.

{^_^}

On 20220709 14:14:56, Ken Sejkora wrote:

Thanks jdow.  I’m pretty confident that this is likely some ‘relatively new’ government/military communication mode, and most likely encrypted.  Trying to demodulate and decrypt the signal(s) is beyond what I’d try to do.  I was just curious as to what insights other users might have.  My point about recording them and looking at the waveform was more to the point of trying to see if the ‘pips’ on a given discrete frequency block are pure CW, or somehow modulated, but if they are very short in duration, that might be hard to determine.

 

As for location, I’m in SE Massachusetts (Cape Cod), so there is no shortage of potential sources within ±40-miles, such as multiple Raytheon and General Dynamics development labs, Navy facility near Newport, RI, submarine bases in Groton, CT and Portsmouth, NH, etc.  However, I’m guessing the origin might be more distant, perhaps one ionospheric skip, but hard to tell.  Kriss up in New Hampshire has also reported them.  Although he’s only ~93 miles away, it seems unlikely we’d both hear the same ‘local’ source on ~15 MHz.

 

Next time I notice them, I’ll try to get onto the Kiwi receiver network to select multiple receiver sites to se where else is ‘seeing’ them at the same time I am.  That might shed a small modicum of light on where the signals are coming from.

 

Thanks for your insights.  Have a great weekend. 73

 

Ken

 

From: jdow
Sent: Saturday, July 9, 2022 02:06 PM
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Mystery mode

 

Roughly speaking where are you located? Are there military or protest sites anywhere near you? That definitely looks like some form of covert comm.

 


Re: SDRC and Airspy R2

jdow
 

5V at a whomping 150 mA. That latter may be the show stopper if you try to use your front end's Bias-T.

And why that version and not "https://www.tgn-technology-online.com/en/Low-Noise-Amplifier-ULNA3018.html"? The "Specifications" suggest it has the power supply. The "Accessories" suggests not. The pictures suggest it does have the PS. Ah, I see, it lacks the bias-T for its PS. If you determine your front end's bias-t can handle the load they all seem to be the same amplifier so the cheapest one should be good enough.

{^_^}

On 20220709 12:21:49, Conrad, PA5Y wrote:

Ah this one does need 5V, there you are then.

 

https://www.tgn-technology-online.com/en/Low-Noise-FM-Amplifier-ULNA3018.html

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:19
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The active device in the TGN amplifiers will not actually need 10V, as you have a bias T in the S3 you should ask TGN if they can use a different regulator in the LNA so that you can use 5V. There are cheaper alternatives.

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 21:09
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Here is a rough and ready analysis with a 6dB attenuator, this would typically be a 10dB step attenuator, set according to conditions.

 

It gives 84dB SFDR based on the S3 user guide and the PGA103+ datasheet. The first 2 stages are typical of a band II amplifier with front end selectivity.

 

Anyway, this gives you an idea.

 

Conrad

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 21:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.

 

I have 25m RG6.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 19:52
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

I could not agree more, a step attenuator on the output is a good idea. You can of course use the noise free bias tee on the S3 for the supply. These are almost certainly PGA103+ LNAs.  You can use AppCAD and do a system noise analysis. If you like I will do one and put it on here. In fact I may have already done one and posted it some time ago. I’ll have a look.

 

Conrad

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 09 July 2022 20:42
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


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Re: PA5Y - 2m Beacon Phase Noise?

Conrad, PA5Y
 

OK then it is the beacon, yes, it is not great.

 

Regards

 

Conrad

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 10 July 2022 08:34
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] PA5Y - 2m Beacon Phase Noise?

 

Well,

 

Using the Q5 Signal with the better-quality oscillator and it's locked toe a Leo Bodnar unit. I see the same with an Airspy and G4LOH is cleaner! I really don't think it's the converter.

 

I expected a beacon to be much cleaner, obviously it's not that easy.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 10 July 2022 07:23
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] PA5Y - 2m Beacon Phase Noise?

 

Hello Simon.

 

It is -70dBc at +/-1kHz, so not as bad as some beacons, but it looks ugly. Are you 100% sure that this is not the LO PN of any converter you may be using? It also seems to have nasty key clicks.

 

Has it degraded?

 

You could compare with the S3 with no converter then you have a known PN in your RX. If it looks the same, then the beacon is grotty.

 

What do your neighbours think?

 

Regards

 

Conrad

 

 

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 10 July 2022 07:58
To: SDR-Radio <main@sdr-radio.groups.io>
Subject: [SDR-Radio] PA5Y - 2m Beacon Phase Noise?

 

Conrad,

 

GB3MCB - any comment?

 

 


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Re: SDRC and Airspy R2

Conrad, PA5Y
 

Does it? I don’t like that idea at all. The specifications say 5V at 150mA.

 

Conrad

  • Frequency 88-108 MHz
  • Gain 10-18 dB variabel
  • Noise figure 0,30 dB
  • 3dB BW typ MHz 70 MHz
  • Max. Outputlevel 119dB/µV
  • Input Return loss min -12dB
  • Output Return loss min -16dB
  • Sttenuation
    • FM   -28dB
    • UHF -45dB
  • Connectors F-F Male
  • DC supply 5V@150mA
  • DC supply via Coaxcabel 5V@150mA
  • Dimensions 99X39X40 mm

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 10 July 2022 08:32
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

It appears they require their own power supply with the gain being controlled by the supply voltage.

 

{^_^}

On 20220709 12:01:14, Simon Brown wrote:

Hi,

 

Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.

 

I have 25m RG6.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 19:52
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

I could not agree more, a step attenuator on the output is a good idea. You can of course use the noise free bias tee on the S3 for the supply. These are almost certainly PGA103+ LNAs.  You can use AppCAD and do a system noise analysis. If you like I will do one and put it on here. In fact I may have already done one and posted it some time ago. I’ll have a look.

 

Conrad

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 09 July 2022 20:42
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


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--

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Re: SDRC and Airspy R2

Simon Brown
 

Ah,

Must read the spec 🙂 .

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of jdow via groups.io <jdow@...>
Sent: 10 July 2022 07:31
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2
 

It appears they require their own power supply with the gain being controlled by the supply voltage.


{^_^}

On 20220709 12:01:14, Simon Brown wrote:

Hi,

Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.

I have 25m RG6.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 19:52
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2
 

I could not agree more, a step attenuator on the output is a good idea. You can of course use the noise free bias tee on the S3 for the supply. These are almost certainly PGA103+ LNAs.  You can use AppCAD and do a system noise analysis. If you like I will do one and put it on here. In fact I may have already done one and posted it some time ago. I’ll have a look.

 

Conrad

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of jdow via groups.io
Sent: 09 July 2022 20:42
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

The cheapest one would probably be good enough. The next one up might be slightly better because you get a nice noisy power supply and (possibly redundant) Bias-T tap for it. The most expensive one would only be needed if you have some exceptionally strong signals nearby.

 

18 dB gain may be a little high with only 2.5 dB of cable loss. Something like one of the old HP 1 dB step variable attenuators might be good on the receiver input. Adjust it for a suitable compromise for dynamic range and signal strength. I suspect you do not need this 10V version of the amplifier.

 

(Did I just save you a bunch of money?)

 

{^_^}

 

On 20220709 11:12:30, Simon Brown wrote:

Thanks,

 

I'll start saving and buy a masthead preamp (below). My income is way down now due to COVID and other cost of living issues. Not a great time to be relying on donations.

 

 

They have a bit of input filtering already, don't know if it's enough.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 17:37
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

According to the user manual with the preamp and noise reduction on the MDS at 91.1MHz is -138dBm in 500Hz, which equates to -165dBm/Hz. This is a 9dB noise figure and is probably 3-6dB worse because the NR makes things appear better than they are. If you add 2.5dB to that noise figure you can see that an LNA will be of great benefit.

 

I suggest that a system noise figure of around 2-3dB is optimum for Band II DXing.

 

Regards

 

Conrad PA5Y

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 17:29
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hi,

 

What's the S3 noise figure on Band II ? I have maybe 2dB loss in the 25m RG6, so am wondering what the total NF is.


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 09 July 2022 16:06
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

BTW I put the BPF before the LNA to help protect it from 144MHz EME high power. I am not suggesting that a PGA103+ will saturate from normal Band II situations. However, it has a little bit too much gain, so a good filter and an attenuator does no harm. The S3 really is excellent. Just like you said 😊

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Conrad, PA5Y via groups.io
Sent: 09 July 2022 17:01
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Hello Simon, I have done a noise analysis and you WILL benefit from an LNA. I have a PGA103+ preceded by a band pass filter and it seems to work very well. However, I am still waiting for a bigger antenna. I ordered an OPTDES which never arrived. So, I will ask a few of the local Band II DXers for an alternative.

 

73

 

Conrad PA5Y

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 09 July 2022 13:22
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

FWIW,

 

The ELAD S3 is the best Band II receiver I have. Am thinking about a preamp on the mast for those very weak stations - if I get close to receiving weak signals from across the pond (USA, Canada).


From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of George Stein - NJ3H via groups.io <nj3h@...>
Sent: 09 July 2022 08:08
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] SDRC and Airspy R2

 

Simon and others,

 

I have attached 3 pictures all with Console running.

 

Elad S2,

Airspy R2

RSPdx

 

 

The RSPdx is the only on of these three that has a decent signal. Running uno is fine also.

 

It is the other two that are causing problems.  The native software yields the same lousy signals.  There is a lot of noise on these two receivers for the station in question. I have fiddles with the R2 slide controls in both Sharp and Console. The Elad appears not to have any RF gain capability.

 

The frequency I am using for this exercise is 98.9, 92 watts, 25 km away.  I am using the same antenna for all three radios.  The antenna is pictured in an attachment. Same feed line to all three radios. My HF+ Discovery works fine also.

 

As I said in a previous message, the Elad S2 is the one that really puzzles me.  I would have expected it to come out the best (based only on price, that is).

 

Anyway, please let me know if more information is needed.

 

Thanks for looking into this.

 

Regards,

George

 

 

 

On Friday, July 8, 2022 at 11:38:57 PM PDT, jdow <jdow@...> wrote:

 

 

Frequency?

{o.o}

On 20220708 14:47:30, George Stein - NJ3H via groups.io wrote:

92 watts not 25.

On Fri, Jul 8, 2022 at 2:24 PM, George Stein -  NJ3H via groups.io

<nj3h@...> wrote:

Further to my last message.  The station in question is 25 km away and running a mere 25 watts. 

Using SDR Console:

With the Elad S2 and and the Airspy R2, the reception was very noisy.

With the Airspy HF+ Discovery and the RSPdx, the signal was full quieting. With the edge going to the HF+ Discovery.

This was not a scientific test, just a casual observation. The only thing I am surprised about was the Elad S2 performance.

I then used the native software for each device and had the same results.

Regards and YMMV,
George


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Re: PA5Y - 2m Beacon Phase Noise?

Simon Brown
 

Well,

Using the Q5 Signal with the better-quality oscillator and it's locked toe a Leo Bodnar unit. I see the same with an Airspy and G4LOH is cleaner! I really don't think it's the converter.

I expected a beacon to be much cleaner, obviously it's not that easy.

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> on behalf of Conrad, PA5Y via groups.io <g0ruz@...>
Sent: 10 July 2022 07:23
To: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io>
Subject: Re: [SDR-Radio] PA5Y - 2m Beacon Phase Noise?
 

Hello Simon.

 

It is -70dBc at +/-1kHz, so not as bad as some beacons, but it looks ugly. Are you 100% sure that this is not the LO PN of any converter you may be using? It also seems to have nasty key clicks.

 

Has it degraded?

 

You could compare with the S3 with no converter then you have a known PN in your RX. If it looks the same, then the beacon is grotty.

 

What do your neighbours think?

 

Regards

 

Conrad

 

 

 

 

 

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Simon Brown via groups.io
Sent: 10 July 2022 07:58
To: SDR-Radio <main@sdr-radio.groups.io>
Subject: [SDR-Radio] PA5Y - 2m Beacon Phase Noise?

 

Conrad,

 

GB3MCB - any comment?

 

 


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