|
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
The 8 element innov is very good, it's worth waiting for. Send Justin a direct mail if you have problems.
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
--
-- - + - + -
|
|
|
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:
toggle quoted message
Show quoted text
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
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
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:
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.
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
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.
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
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
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).
I have attached 3
pictures all with Console running.
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.
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
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
--
--
--
|
|
|
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
The 8 element innov is very good, it's worth waiting for. Send Justin a direct mail if you have problems.
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
--
|
|
|
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
-- - + - + -
|
|
|
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
|
|
|
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.)
toggle quoted message
Show quoted text
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
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:
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.
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
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.
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
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
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).
I have attached 3 pictures all with Console running.
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.
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
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
--
--
--
|
|
|
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:
toggle quoted message
Show quoted text
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
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.
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).
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
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
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
Please do a noise analysis for
88-108MHz. I think the S3 bias-t is 5v, not sure what
voltage these preamps require.
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
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:
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.
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
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.
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
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
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).
I have
attached 3 pictures all with
Console running.
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.
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
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
--
--
--
--
--
|
|
|
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:
toggle quoted message
Show quoted text
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.
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).
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
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
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
Please do a noise analysis for
88-108MHz. I think the S3 bias-t is 5v, not sure what
voltage these preamps require.
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
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:
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.
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
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.
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
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
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).
I have
attached 3 pictures all with Console
running.
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.
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
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
--
--
--
--
--
- + - + -
|
|
|
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:
toggle quoted message
Show quoted text
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
-
Connectors F-F Male
-
DC supply 5V@150mA
-
DC supply via Coaxcabel 5V@150mA
-
Dimensions 99X39X40 mm
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:
Please do a noise analysis for
88-108MHz. I think the S3 bias-t is 5v, not sure what
voltage these preamps require.
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
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:
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.
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
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.
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
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
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).
I have attached
3 pictures all with Console running.
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.
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
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
--
--
--
--
|
|
|
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.
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).
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.
{^_^}
toggle quoted message
Show quoted text
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
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
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
Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.
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
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:
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.
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
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.
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
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
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).
I have attached 3 pictures all with Console running.
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.
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
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
--
--
--
--
--
|
|
|
Check out the analysis Conrad posted.
{^_-}
On 20220709 14:57:45, Siegfried
Jackstien wrote:
toggle quoted message
Show quoted text
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
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:
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.
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
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.
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
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
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).
I have attached 3
pictures all with Console running.
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.
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
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
--
--
--
|
|
|
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:
toggle quoted message
Show quoted text
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
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:
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.
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
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.
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
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
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).
I have attached 3
pictures all with Console running.
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.
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
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
--
--
--
|
|
|
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.
{^_^}
toggle quoted message
Show quoted text
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
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
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
Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.
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
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:
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.
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
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.
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
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
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).
I have attached 3 pictures all with Console running.
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.
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
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
--
--
--
--
-- - + - + -
|
|
|
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.
{^_^}
toggle quoted message
Show quoted text
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
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
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
Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.
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
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:
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.
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
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.
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
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
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).
I have attached 3 pictures all with Console running.
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.
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
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
--
--
--
--
|
|
|
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:
toggle quoted message
Show quoted text
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
Roughly speaking where are you located? Are there military or
protest sites anywhere near you? That definitely looks like
some form of covert comm.
|
|
|
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:
toggle quoted message
Show quoted text
Ah
this one does need 5V, there you are then.
https://www.tgn-technology-online.com/en/Low-Noise-FM-Amplifier-ULNA3018.html
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
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
Please do a noise analysis for 88-108MHz.
I think the S3 bias-t is 5v, not sure what voltage these
preamps require.
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
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:
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.
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
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.
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
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
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).
I have attached 3
pictures all with Console running.
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.
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
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
--
--
--
--
|
|
|
Re: PA5Y - 2m Beacon Phase Noise?
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?
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.
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
--
--
|
|
|
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
-
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.
{^_^}
toggle quoted message
Show quoted text
On 20220709 12:01:14, Simon Brown wrote:
Please do a noise analysis for 88-108MHz. I think the S3 bias-t is 5v, not sure what voltage these preamps require.
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
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:
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.
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
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.
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
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
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).
I have attached 3 pictures all with Console running.
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.
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
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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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:
toggle quoted message
Show quoted text
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.
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
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:
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.
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
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.
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
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
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).
I have attached 3 pictures all with Console running.
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.
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
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?
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