Date   

Re: Build Experimental Loop for LF to HF.

Mag loop Simon
 

Hi

In my honest opinion..

Ferrite antennas are really down on sensitivity compared to tuned mag loops. ( tried it.)


Useful for dfing..but no one uses them for low noise dx Rx antennas..there is a good reason for this ..

Ok if one builds a ferrite antenna from LOTS of bars then they can start to be of use..but y? When can do much better with a rx only multi turn loop. ( less cost more Q etc.)


Re varicap diodes for tuning..been done for years..problem now is finding suitable diodes..and really they make any difference to imds etc with the small voltages developed across loop, ( unless real close to AM broadcast station etc.)

Main issue with remote high Q loop antennas is tuning..this can easy be got around with stepper motor..

I have alot of experience with loop antennas..I use a LARGE one for 160m tx..

Simon g0zen


Re: Build Experimental Loop for LF to HF.

Allan Isaacs
 

Interesting, but do the advantages outweigh the disadvantages?

The fact that you’re tuning a specific signal with a significant degree of selectivity means that you’re unlikely to notice the effects of a strong out of band signal? If you do get problems you can null out the unwanted signal by turning the ferrite rod. The end result will be much the same as using a portable radio with its ferrite rod.

Would switching diodes used in some front ends have much the same problem?

 

I’ll do some experiments when I have time.

I suppose if the aerial coil is tuned to a really strong SSB signal the varicap voltage will swing a little and widen the tuning response curve?

 

Allan G3PIY

 


From: main@SDR-Radio.groups.io [mailto:main@SDR-Radio.groups.io] On Behalf Of jdow
Sent: 06 December 2020 12:49
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Build Experimental Loop for LF to HF.

 

How do you keep the varicap from causing all manner of IMD, some of it pretty exotic? Don't forget that the tuning voltage is "modulated" by the signal voltages in the tuned circuit.

{o.o}

On 20201206 02:19:50, Allan Isaacs wrote:

Hi Paul

Try a varicap and a ferrite rod.

A lot easier to handle and you do not need a ladder to adjust it when on top of a pole.

http://www.radiomuseum.co.uk/active.html

Allan G3PIY

 


Re: Build Experimental Loop for LF to HF.

jdow
 

How do you keep the varicap from causing all manner of IMD, some of it pretty exotic? Don't forget that the tuning voltage is "modulated" by the signal voltages in the tuned circuit.

{o.o}

On 20201206 02:19:50, Allan Isaacs wrote:

Hi Paul

Try a varicap and a ferrite rod.

A lot easier to handle and you do not need a ladder to adjust it when on top of a pole.

http://www.radiomuseum.co.uk/active.html

Allan G3PIY

 


From: main@SDR-Radio.groups.io [mailto:main@SDR-Radio.groups.io] On Behalf Of Paul Cianciolo
Sent: 06 December 2020 00:57
To: main@SDR-Radio.groups.io
Subject: [SDR-Radio] Build Experimental Loop for LF to HF.

 

Hello All,
I made a video for folks who want to build a n air core loop but are not sure about the dimensions needed for a particular frequencies of interest.
This video show how build a reusable form air core loop and answers a lot of question folks have been asking.

https://youtu.be/bjerUrTvSJk

W1VLF

 

 



Re: Audio Distortion - Cannot Decode FT8 #airspyr2

jdow
 

If you mean me I'll probably just compile what Microsoft supplies as an example in their Driver Development Kit. I simply noted the discussion on the forum and tried to point you there.

{o.o}

On 20201205 03:25:34, Dr.Alexander Hahn wrote:
Which program are you using as a virtual audio cable?


Re: Build Experimental Loop for LF to HF.

Allan Isaacs
 

Hi Paul

Try a varicap and a ferrite rod.

A lot easier to handle and you do not need a ladder to adjust it when on top of a pole.

http://www.radiomuseum.co.uk/active.html

Allan G3PIY

 


From: main@SDR-Radio.groups.io [mailto:main@SDR-Radio.groups.io] On Behalf Of Paul Cianciolo
Sent: 06 December 2020 00:57
To: main@SDR-Radio.groups.io
Subject: [SDR-Radio] Build Experimental Loop for LF to HF.

 

Hello All,
I made a video for folks who want to build a n air core loop but are not sure about the dimensions needed for a particular frequencies of interest.
This video show how build a reusable form air core loop and answers a lot of question folks have been asking.

https://youtu.be/bjerUrTvSJk

W1VLF

 

 


Re: Build Experimental Loop for LF to HF.

Dave (NK7Z)
 

Hi Paul,
Thanks for the info on the loop! Nicely done!

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 12/5/20 4:57 PM, Paul Cianciolo wrote:
Hello All,
I made a video for folks who want to build a n air core loop but are not sure about the dimensions needed for a particular frequencies of interest.
This video show how build a reusable form air core loop and answers a lot of question folks have been asking.
https://youtu.be/bjerUrTvSJk
W1VLF


Build Experimental Loop for LF to HF.

Paul Cianciolo
 

Hello All,
I made a video for folks who want to build a n air core loop but are not sure about the dimensions needed for a particular frequencies of interest.
This video show how build a reusable form air core loop and answers a lot of question folks have been asking.

https://youtu.be/bjerUrTvSJk

W1VLF

 


Re: Mystery Signal on 20-Meters

Brendan Wahl
 

Hi Roger,

I've not seen much 'new' info for sometime now. The frequencies in use are the most recent datapoints, and since this is private industry, they seem to be good at keeping all else fairly private. What is yet to be found is the use of this outside of US>EU paths, say AS>US. Taking advantage of the markets on a 24 hour basis with a faster order transmission system would seem to be desirable for trading firms all over the world. Money from milliseconds.

Brendan WA7HL


For Sale is a RFSpace NetSDR

Everett N4CY
 

If any one is interested in buying a top of the line SDR I am selling my RFSpace NetSDR. It is in excellent condition and works great. It will work on SDR Console, SDR# and SpectraVue software. It has the downconverter option which extends coverage to 800MHz.

Please contact me at everettsharp@... for more information.
 
Everett N4CY



Re: Mystery Signal on 20-Meters

Brendan Wahl
 

I'll give the "Sniper In Mahwah" postings the credit for my knowledge - quite interesting to see what these folks are spending their money on. I'm curious to see what modes they are indeed using and if there is likely to be any spill over outside the financial industry for this tech.

Brendan WA7HL


Re: Audio Distortion - Cannot Decode FT8 #airspyr2

Alex DH2ID
 

Which program are you using as a virtual audio cable?


Re: Audio Distortion - Cannot Decode FT8 #airspyr2

jdow
 

Not at 24.915 MHz, I suspect. (Hm, with either "." or "," separators. He has a US call sign so it's "about" 25 MHz as he cited it. That is on the ragged edge of R820 type tuners. I'd expect stability problems with it. (If he is using a converter I'd expect it to just flat not work given most conveters. A GPS stabilized Spyverter might work.)

{^_^}

On 20201204 11:56:08, Simon Brown wrote:

Mike,

 

In the forums (URL at the bottom) post this problem and a screenshot so we can see your settings. WSJT should be fine.

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Paul Robertson
Sent: 04 December 2020 19:06
To: main@sdr-radio.groups.io
Subject: Re: [SDR-Radio] Audio Distortion - Cannot Decode FT8 #airspyr2

 

Just a thought. Did you sync the time setting on your computer?

 

Paul VE3HFQ

 



On Dec 4, 2020, at 1:45 PM, Mike <bipi@...> wrote:

Using an Airspy R2. Computer is Dell Tower,Intel 10th Generation Quad I,Graphic Card NVIDIA GeForce GTX 1660T,Memory (RAM) 32 G,Windows 10 Pro

Test case 24.915 MHz ham radio FT8 frequency and WSJT-X, V2.2.2


Received audio to speaker or virtual cable is mushy/distorted. The audio spectrum of received signals on the WSJT-X waterfall appear mushy and poorly defined. Signals will not decode. Changed SDR to an SDR-IQ. Signals are clearly defined on the WSJT waterfall and all signals are decoded.

I have tried reinstalling the software and adjusting all the settings I can find but there is no change. Does anyone have any suggestions? I purchased the Airspy R2 for weak signal VHF/UHF meteor scatter and Es propagation. I have jpg picture files of the V3 screen, WSJT-X Airspy window, and the WSJT-X SDR-IQ window but I don't know how to attach them here.

Thank You
Mike
K7PI


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


Re: Audio Distortion - Cannot Decode FT8 #airspyr2

jdow
 

The AirSpy R2 is not rated for use at 24.915 MHz. Do you mean Discovery or something?

Visit the forum. I believe somebody had this trouble and got it working by fiddling the settings of the toy that fits between the SDR software and WSJT.

{^_^}

On 20201204 10:44:59, Mike wrote:
Using an Airspy R2. Computer is Dell Tower,Intel 10th Generation Quad I,Graphic Card NVIDIA GeForce GTX 1660T,Memory (RAM) 32 G,Windows 10 Pro

Test case 24.915 MHz ham radio FT8 frequency and WSJT-X, V2.2.2


Received audio to speaker or virtual cable is mushy/distorted. The audio spectrum of received signals on the WSJT-X waterfall appear mushy and poorly defined. Signals will not decode. Changed SDR to an SDR-IQ. Signals are clearly defined on the WSJT waterfall and all signals are decoded.

I have tried reinstalling the software and adjusting all the settings I can find but there is no change. Does anyone have any suggestions? I purchased the Airspy R2 for weak signal VHF/UHF meteor scatter and Es propagation. I have jpg picture files of the V3 screen, WSJT-X Airspy window, and the WSJT-X SDR-IQ window but I don't know how to attach them here.

Thank You
Mike
K7PI



Re: Mystery Signal on 20-Meters

Roger Need
 

On Fri, Dec 4, 2020 at 12:41 PM, Kriss Kliegle KA1GJU wrote:
Already been done:
https://www.hfunderground.com/board/index.php/topic,44885.0.html

More info here:
https://sniperinmahwah.wordpress.com/2018/05/07/shortwave-trading-part-i-the-west-chicago-tower-mystery/
 
Thanks.

I was looking for recent posts.  These transmissions are all over the HF frequencies now.
Roger


Re: Mystery Signal on 20-Meters

Kriss Kliegle KA1GJU
 


Re: Mystery Signal on 20-Meters

Roger Need
 

On Tue, Dec 1, 2020 at 08:37 AM, Brendan Wahl wrote:
Hi all,

That's one of the High Frequency Trader signals that you see above 20
meters. These are low-latency, fixed simplex circuits providing
commodities traders with a faster-than-cable-or-satellite way to submit
orders to the markets. Primarily used for US Midwest to Europe paths for
now, and AS to USA may be under experimentation or so I've heard, but I
haven't confirmed this.
A number of other folks did the necessary sleuthing on this, and the FCC
database as usual provided much of the info. It just had to be pieced
together.

Brendan WA7HL
Do you have a link to any recent investigations or discussion concerning these shortwave stock trading transmissions?  I think it might be interesting to use the  kiwisdr direction finding feature to pinpoint the transmitter location.

Roger


Re: Audio Distortion - Cannot Decode FT8 #airspyr2

Simon Brown
 

Mike,

 

In the forums (URL at the bottom) post this problem and a screenshot so we can see your settings. WSJT should be fine.

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Paul Robertson
Sent: 04 December 2020 19:06
To: main@sdr-radio.groups.io
Subject: Re: [SDR-Radio] Audio Distortion - Cannot Decode FT8 #airspyr2

 

Just a thought. Did you sync the time setting on your computer?

 

Paul VE3HFQ

 



On Dec 4, 2020, at 1:45 PM, Mike <bipi@...> wrote:

Using an Airspy R2. Computer is Dell Tower,Intel 10th Generation Quad I,Graphic Card NVIDIA GeForce GTX 1660T,Memory (RAM) 32 G,Windows 10 Pro

Test case 24.915 MHz ham radio FT8 frequency and WSJT-X, V2.2.2


Received audio to speaker or virtual cable is mushy/distorted. The audio spectrum of received signals on the WSJT-X waterfall appear mushy and poorly defined. Signals will not decode. Changed SDR to an SDR-IQ. Signals are clearly defined on the WSJT waterfall and all signals are decoded.

I have tried reinstalling the software and adjusting all the settings I can find but there is no change. Does anyone have any suggestions? I purchased the Airspy R2 for weak signal VHF/UHF meteor scatter and Es propagation. I have jpg picture files of the V3 screen, WSJT-X Airspy window, and the WSJT-X SDR-IQ window but I don't know how to attach them here.

Thank You
Mike
K7PI


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


Re: Audio Distortion - Cannot Decode FT8 #airspyr2

Mike
 

Thanks for the response...Yes, time is GPS controlled on my computer...uses multiple satellites to continuously correct the time.

Mike K7PI


Re: Audio Distortion - Cannot Decode FT8 #airspyr2

Paul Robertson
 

Just a thought. Did you sync the time setting on your computer?

Paul VE3HFQ


On Dec 4, 2020, at 1:45 PM, Mike <bipi@...> wrote:

Using an Airspy R2. Computer is Dell Tower,Intel 10th Generation Quad I,Graphic Card NVIDIA GeForce GTX 1660T,Memory (RAM) 32 G,Windows 10 Pro

Test case 24.915 MHz ham radio FT8 frequency and WSJT-X, V2.2.2


Received audio to speaker or virtual cable is mushy/distorted. The audio spectrum of received signals on the WSJT-X waterfall appear mushy and poorly defined. Signals will not decode. Changed SDR to an SDR-IQ. Signals are clearly defined on the WSJT waterfall and all signals are decoded.

I have tried reinstalling the software and adjusting all the settings I can find but there is no change. Does anyone have any suggestions? I purchased the Airspy R2 for weak signal VHF/UHF meteor scatter and Es propagation. I have jpg picture files of the V3 screen, WSJT-X Airspy window, and the WSJT-X SDR-IQ window but I don't know how to attach them here.

Thank You
Mike
K7PI


Audio Distortion - Cannot Decode FT8 #airspyr2

Mike
 
Edited

Using an Airspy R2. Computer is Dell Tower,Intel 10th Generation Quad I7,Graphic Card NVIDIA GeForce GTX 1660T,Memory (RAM) 32 G,Windows 10 Pro

Test case 24.915 MHz ham radio FT8 frequency and WSJT-X, V2.2.2


Received audio to speaker or virtual cable is mushy/distorted. The audio spectrum of received signals on the WSJT-X waterfall appear mushy and poorly defined. Signals will not decode. Changed SDR to an SDR-IQ. Signals are clearly defined on the WSJT waterfall and all signals are decoded.

Just loaded SDR Sharp with Airspy R2 and WSJT-X decoding fine...so the issue does appear to be with V3.

I have tried reinstalling the software and adjusting all the settings I can find but there is no change. Does anyone have any suggestions? I purchased the Airspy R2 for weak signal VHF/UHF meteor scatter and Es propagation. I have jpg picture files of the V3 screen, WSJT-X Airspy window, and the WSJT-X SDR-IQ window but I don't know how to attach them here.

Thank You
Mike K7PI

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