Date   

Guide "Using_I-Q_signals_between_SDRUno_and_MultiPSK" by Fred

Patrick Lindecker
 

Hello to all,

 

Fred (thanks to him!) writes this guide "Using_I-Q_signals_between_SDRUno_and_MultiPSK". It is aimed to help the ones who want to connect the SDRUno program (for SDRplay receivers) to Multipsk in a SdR way (i.e. through I/Q signals): Using_I-Q_signals_between_SDRUno_and_MultiPSK.pdf

 

73

Patrick


Re: LRPT Laboratory Bandwidth testing

David J Taylor
 

On 22/12/2020 13:25, Fred Albertson wrote:
Hi David,
I don't think so, because they decode ad BMP's from AMIGOS.  I convert
them to JPG's for the e-mail.  I have noticed no difference.
Thanks and great day,
Fred
Thanks, Fred.

At least one references suggests it's JPEG data:

http://jmfriedt.free.fr/glmf_meteor_eng.pdf
https://www.rtl-sdr.com/forum/viewtopic.php?t=343

If so, it might be better to work in the JPEG space rather than go JPEG=>BMP=>JPEG. BMP is much more convenient for subsequent processing, of course.

I'm uncertain whether or not JPEG=>BMP decoding always produces the same results or whether some assumptions are made (beyond the tables included with the JPEG data) which affect the results.

73,
David GM8ARV
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv


Re: LRPT Laboratory Bandwidth testing

Fred Albertson
 

Hi David,

I don't think so, because they decode ad BMP's from AMIGOS.  I convert
them to JPG's for the e-mail.  I have noticed no difference.

Thanks and great day,

Fred


LRPT Laboratory Bandwidth testing

Fred Albertson
 

Hi Patrick,

This morning, on a medium quality pass, I used the RSP with no filters or amps. Again I used the 120kHz filter which
does not seem to affect the picture quality at all.  One thing I note is that the picture lines are more consistent
between the frames.

Question, In the I/Q mode is the Global Level relevant?   It did not go above 2% for this pass.  I did not correct
the RSP gain at all.

64                                                                               65                                                                             68


Great day,

Fred


#Beginner #Beginner

fly.fechter@t-online.de
 

Hello,
I just managed to install my Airspy mini and use it to run SDR sharp..
I would like to link - set-up the latter to  Multipsk VDL 2.
I would be most obliged to learn the exact settings to both - SDRsharp and Multipsk VDL 2 - to achieve smooth decoding of VDL 2 signals.
Respective clear screen shots  would be ideal.
Thank you very much in advance.
Regards,
Roland


Re: LRPT Laboratory Bandwidth testing

David J Taylor
 

On 21/12/2020 22:14, Patrick Lindecker wrote:
Hello Fred,
[]
I looked at these lines. In fact, they are 8 pixels width. A line must be composed of elementary small pictures of 8x8 pixels, transported by one or several bad received frames.
73
Patrick
JPEG chunks, perhaps?

73,
David GM8ARV
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv


Re: LRPT Laboratory Bandwidth testing

Patrick Lindecker
 

Hello Fred,

 

TKS for the LRPT pictures.

 

>I was using the Sawbird but kept the signal levels low (which may help, or hurt, I don't know yet). 

If you can avoid it, better is to avoid. In my opinion, even if of good quality, it brings a small signal degradation.


>Anyway, beautiful snow pictures, but plenty of lines. 

I looked at these lines. In fact, they are 8 pixels width. A line must be composed of elementary small pictures of 8x8 pixels, transported by one or several bad received frames.

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Fred Albertson
Envoyé : lundi 21 décembre 2020 15:06
À : multipsk@groups.io
Objet : [multipsk] LRPT Laboratory Bandwidth testing

 

Hi Patrick, Andrea, Josef, et al,

Using the I/Q output from my RSPduo into MultiPSK (still refining the procedure), I decoded an almost perfect
pass this morning at 1318Z.  M2 was 88 degrees overhead and 826kM away.  The NORAD altitude information shows:

Perigee: 825.3 km
Apogee: 835.1 km


So it was about as close as it is going to get until it falls out of the sky!

The only problem was that NOAA19 came wandering in at about 1328Z, which halted the decode.  By that time
I had about 3700 synchros, and some pretty good pictures:

64                                                                              65                                                                             68                                                                             R-G-IR


I was using the Sawbird but kept the signal levels low (which may help, or hurt, I don't know yet). 

My theory was that narrowing the bandwidth, by using the 120kHz filter in the RSP, vice the full 192kHz,
would keep the VDL2 signals (136.975kHz), which I receive loud and clear, out of the signal that AMIGOS,
was seeing.  I believe that I did that effectively. I can not tell for sure that other VHF signals are not in
the bandwidth, but continuous manual monitoring with no satellite in view does not show interference.

Anyway, beautiful snow pictures, but plenty of lines. 

This is an Alpha level report, so I am not drawing any conclusions.

Thoughts?

Great Day,

Fred



Re: #Beginner #Beginner

WB9EZB
 

I was able to decode VDL2 using an external soundcard by connecting the output of the sound card to the input of the sound card with rca jumpers.
You must be careful with levels.
Your receiver needs to have a bandwidth of at least 25 Khz and have the ability to demodulate SSB.  VB cable can
Connect an SDR dongle to Multipsk by software.The best option is to use the IQ interface which Patrick has installed. I run a SDR play radio to Multipsk.  Works Great !


On Dec 21, 2020, at 2:09 PM, Patrick Lindecker <f6cte@...> wrote:



Hello,

 

To connect a receiver, you must simply connect an AF output to the sound card input of your PC. Then you have to select this sound card on the “Sound-card (input)” command of the Configuration screen menu.

 

Of course, you will be limited to the small bandwidth modes (so no VDL2, LRPT, RDS…).

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de fly.fechter@...
Envoyé : lundi 21 décembre 2020 10:17
À : multipsk@groups.io
Objet : [multipsk] #Beginner

 

Hello,
Can somebody please tell me the exact settings required for linking Multipsk VDL2 to my radio-receiver AR8600-
or point out to me a suitable link containing this information ?
Thanks in advance.
Regards
Roland 





Re: #Beginner #Beginner

Patrick Lindecker
 

Hello,

 

To connect a receiver, you must simply connect an AF output to the sound card input of your PC. Then you have to select this sound card on the “Sound-card (input)” command of the Configuration screen menu.

 

Of course, you will be limited to the small bandwidth modes (so no VDL2, LRPT, RDS…).

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de fly.fechter@...
Envoyé : lundi 21 décembre 2020 10:17
À : multipsk@groups.io
Objet : [multipsk] #Beginner

 

Hello,
Can somebody please tell me the exact settings required for linking Multipsk VDL2 to my radio-receiver AR8600-
or point out to me a suitable link containing this information ?
Thanks in advance.
Regards
Roland 


LRPT Laboratory Bandwidth testing

Fred Albertson
 

Hi Patrick, Andrea, Josef, et al,

Using the I/Q output from my RSPduo into MultiPSK (still refining the procedure), I decoded an almost perfect
pass this morning at 1318Z.  M2 was 88 degrees overhead and 826kM away.  The NORAD altitude information shows:

Perigee: 825.3 km
Apogee: 835.1 km

So it was about as close as it is going to get until it falls out of the sky!

The only problem was that NOAA19 came wandering in at about 1328Z, which halted the decode.  By that time
I had about 3700 synchros, and some pretty good pictures:

64                                                                              65                                                                             68                                                                             R-G-IR


I was using the Sawbird but kept the signal levels low (which may help, or hurt, I don't know yet). 

My theory was that narrowing the bandwidth, by using the 120kHz filter in the RSP, vice the full 192kHz,
would keep the VDL2 signals (136.975kHz), which I receive loud and clear, out of the signal that AMIGOS,
was seeing.  I believe that I did that effectively. I can not tell for sure that other VHF signals are not in
the bandwidth, but continuous manual monitoring with no satellite in view does not show interference.

Anyway, beautiful snow pictures, but plenty of lines. 

This is an Alpha level report, so I am not drawing any conclusions.

Thoughts?

Great Day,

Fred




#Beginner #Beginner

fly.fechter@t-online.de
 

Hello,
Can somebody please tell me the exact settings required for linking Multipsk VDL2 to my radio-receiver AR8600-
or point out to me a suitable link containing this information ?
Thanks in advance.
Regards
Roland 


LRPT Laboratory and RSP I/Q Input

Fred Albertson
 


Hello Fred,

 

>I have been successful in getting the RSP - Multipsk link to operate
>in the I/Q mode at 192/16.  A lot to configuring and testing, and an
It would be interesting to have a small abstract on the way you get this working, as it does not seem very simple…

Will do.

 

>tied it in both RDS and LRPT modes.
Did you read the RDS messages from FM radio?

Yes

 

>Now I should be able to better control the bandwidth of the M2
>receive signal on the RSP. My intent is to narrow the 137.1 signal to
>drop any VDL2 data off the edge. 

Interesting experience, even I’m skeptical, but who knows…

I'm sceptical too, but it another piece of the puzzle.


>We got about 8" here.

20 cm ! Nice for children, not so for adults.

Correct!!! Especially old adults 😉

 

Fred

 

 


Re: LRPT Laboratory and RSP I/Q Input

Patrick Lindecker
 

Hello Fred,

 

>I have been successful in getting the RSP - Multipsk link to operate
>in the I/Q mode at 192/16.  A lot to configuring and testing, and an
It would be interesting to have a small abstract on the way you get this working, as it does not seem very simple…

 

>tied it in both RDS and LRPT modes.
Did you read the RDS messages from FM radio?

 

>Now I should be able to better control the bandwidth of the M2
>receive signal on the RSP. My intent is to narrow the 137.1 signal to
>drop any VDL2 data off the edge. 

Interesting experience, even I’m skeptical, but who knows…


>We got about 8" here.

20 cm ! Nice for children, not so for adults.

 

73

Patrick

 

 

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Fred Albertson
Envoyé : jeudi 17 décembre 2020 14:49
À : multipsk@groups.io
Objet : Re: [multipsk] LRPT Laboratory and RSP I/Q Input

 

Hi Patrick, Andrea, and Mike,

I have been successful in getting the RSP - Multipsk link to operate
in the I/Q mode at 192/16.  A lot to configuring and testing, and an
update of VAC to 4.64.0, now allows a very good connection. I have
tied it in both RDS and LRPT modes.

Now I should be able to better control the bandwidth of the M2
receive signal on the RSP. My intent is to narrow the 137.1 signal to
drop any VDL2 data off the edge. 

I have had no test time with good M2 passes, but, at least, the setup
is functional.

More later.

===

Here is a look at the east coast of the USA and its blanket of snow,
some of which I am now going to try to remove from my driveway.
We got about 8" here. Do not pay attention to the lines in this one:





Great day,

Fred


Re: LRPT Laboratory and RSP I/Q Input

Fred Albertson
 

Hi Patrick, Andrea, and Mike,

I have been successful in getting the RSP - Multipsk link to operate
in the I/Q mode at 192/16.  A lot to configuring and testing, and an
update of VAC to 4.64.0, now allows a very good connection. I have
tied it in both RDS and LRPT modes.

Now I should be able to better control the bandwidth of the M2
receive signal on the RSP. My intent is to narrow the 137.1 signal to
drop any VDL2 data off the edge. 

I have had no test time with good M2 passes, but, at least, the setup
is functional.

More later.

===

Here is a look at the east coast of the USA and its blanket of snow,
some of which I am now going to try to remove from my driveway.
We got about 8" here. Do not pay attention to the lines in this one:





Great day,

Fred


Re: I/Q input?

Patrick Lindecker
 

Hello Mike,

 

In SdR mode (i.e “Direct via the soundcard” button pushed) , Multipsk accepts I/Q signals as input on the sound card (Funcube receivers are interfaced to Multipsk in this way).

The SdR demodulation is made by Multipsk and the SdR spectrum appears in the “I/Q direct interface…” window.

 

However the formats are precise:

·         On all modes except LRPT and RDS: 48 kHz, stereo (I/Q), 16 bits

·         For LRPT and RDS: 192 kHz, stereo (I/Q), 16 bits.

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de mike agner
Envoyé : dimanche 13 décembre 2020 02:36
À : multipsk@groups.io
Objet : [multipsk] I/Q input?

 

I have a feeling the answer is no, but I'll ask - can MultiPSK accept an I/Q signal as input?   Thanks....Mike


Re: CPDLC/HFDL

Josef Garcia
 

Thanks Paul!

73 Josef 
DE3JGA


Re: CPDLC/HFDL

Paul Gulliver
 

This program will decode these messages using a RPi or similar https://github.com/szpajder/dumpvdl2

Paul

On 12/12/2020 at 19:21, Patrick Lindecker <f6cte@...> wrote:

No it does no decode these messages (as I don’t know what they exactly are). I think that it exists a decoding under Linux which decodes these messages.

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de Josef Garcia
Envoyé : samedi 12 décembre 2020 09:13
À : multipsk@groups.io
Objet : Re: [multipsk] CPDLC/HFDL

 

Hello,

 

another question: Can Multipsk automatically decode the FANS-1/A-CPDLC messages under VDL2?

 

Thank you! 

73 Josef
DE3JGA



Re: CPDLC/HFDL

Josef Garcia
 

Thanks Patrick for the information!

73 Josef
DE3JGA


Re: I/Q input?

Fred Albertson
 

Hi Mike,

I have had success with the I/Q output from an RSPduo at bandwidths
up to 48kHz.  I use VAC and set the input to MultiPSK to that cable number.

I am trying to do it at 192kHz, but I am having trouble getting the circuit
set up to move that bandwidth data.

Hope this helps,

Fred


I/Q input?

mike agner
 

I have a feeling the answer is no, but I'll ask - can MultiPSK accept an I/Q signal as input?   Thanks....Mike

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