Topics

locked PC Panadapter using G90 I/Q output.

W5DXP
 

Today, I plugged a stereo cable into the G90 I/Q output and into a USB sound card dongle, launched SDR# and bingo - instant panadapter. I took a look at the FT8 signals on 14.074 MHz, USB. Here's what I saw:

Robert L. Paris Sr.
 

Hi Ceil Moore,

    I have the Xiegu G90 and an External Sound Card Dongle connected to my Toshiba Windows 10 Notebook. I am most interested in getting the spectrum scope and water fall displayed on my Toshiba Notebook lager screen.

    Could I download and install the SDR# Sharp software. Then connect the Xiegu G90 to my dongle sound card via a stereo patch cable from the I/Q port on the back of the Xiegu 90 and pick chose the right things on the SDR# software and get an “instant PC Pandapter” using the Xiegu G90? And would that display a spectrum or band scope and water fall on the General Class Phone portion of 40 and 20 Meters HF? I not really interested in the FT8 or digital signals displayed.

   What selections should I make on the SDR# software for input from the Xiegu G90 to the sound card dongle? What did you use for settings?

    Thanks for the interesting post on the message group!

73 Bob Sr.

Kb8pqm

 

 

From: XieguG90@groups.io <XieguG90@groups.io> On Behalf Of cecil moore
Sent: Saturday, June 29, 2019 10:18 PM
To: XieguG90@groups.io
Subject: [XieguG90] PC Panadapter using G90 I/Q output.

 

Today, I plugged a stereo cable into the G90 I/Q output and into a USB sound card dongle, launched SDR# and bingo - instant panadapter. I took a look at the FT8 signals on 14.074 MHz, USB. Here's what I saw:

W5DXP
 

I am by no means a G90 or SDR# expert. I have my G90 set up for digital modes, i.e. . Here is my display for 14.263 MHz SSB. The stuff in the center appears to be birdies from the down-conversion but you can see a couple of SSB signals. The SDR# span is set for wide-band FM at about 180 kHz. If those are conversion birdies, I don't know how to get rid of them. I'm a "try it and see" type guy. I tried it and it works.

W5DXP
 

Additional information for using the I/Q output as a PC Panadapter. Note that I have no hardware low-pass filter on the I/Q signal.

1. My desktop has a discrete connector for the stereo microphone input. My laptop has a TRRS (tip, ring, ring, sleeve) connector for both stereo sound output and mono mic input - can't use a mono mic input for I/Q - must be stereo.

2. In SDR#, the source selection must be "IQ from sound card". Also on my PC, SDR# won't work for IQ input if external speakers are plugged in - in which case all I get on the display is noise - don't know why.

3. Of course, in Windows 10, whatever stereo microphone input that one is using must be the selected/default microphone in the sound settings and the levels must be properly set.

To get rid of the above VFO severe birdie/aliasing, I set the VFO for 7073 and displayed 7074-7076.5. Here's what the FT8 signals looked like:

Bob Bryce
 

Hi W5DXP
Congratulations!  
Can you advise on the strong and regular vertical lines?  I wondered if this was either some kind of grid from sdr#, or is it actual signals spread every 100Hz or so?

Keep up the great work - it's really helpful to others..
Bob, MM0MMQ

W5DXP
 

Bob, I'm guessing those vertical lines are aliasing lines caused by not having a hardware lowpass filter but that is just a guess. Xiego has not published the specifications for the I/Q signal output so we are just shooting in the dark so far. I assume a lowpass filter is needed with a cutoff frequency of 1/2 the sample frequency. I can't tell much difference between the 48k and 192k sampling results.

Bob Bryce
 

Thank you W5DXP, all inputs really helpful!  
You are right in that we are working in the dark until we can source some technical info. You have answered my question though - it's not gridlines....   Also, I wouldn't expect the results of aliasing (lack of lo pass filter) to be causing regularly spaced spot frequencies (plus they don't even look modulated?). It more has the look of some kind of beat between two frequencies closely related and I cannot even guess what's happening there. The I and Q signals arise from quadrature modulation but that comes from two identical frequencies locked together via 90 degree phase shift so not that!

Do we have anyone in the Group that has a contact in Xiegu? I heard (Bob Nagy?) that the spec  to for wasthe IQ output was be released around the time that the add-on 5" display was announced but I've seen no marketing info on a date for that.

I've only had my G90 for three weeks but I've been on hold in the Scottish Highlands for the last two - so really looking forward to the 're-union' tonight (ha!). I've built an endfed antenna as my first experience and now looking to build a doublet using kit from DC Commander.

Regards
Bob, MM0MMQ

W5DXP
 

Bob, those vertical lines are visible in the other two graphics that I posted earlier with maximum magnitudes at the G90 VFO frequency. I called them "birdies" in my earlier postings.

"bg8pd
 

Hi bob, as I know,the GSOC(add-on panadapter ) is still under development.
The control unit has completed the design and has been trial-produced.




------------------ Original ------------------
From: Bob Bryce <bob.bryce@...>
Date: Thu,Aug 15,2019 4:28 PM
To: XieguG90 <XieguG90@groups.io>
Subject: Re: [XieguG90] PC Panadapter using G90 I/Q output.

Thank you W5DXP, all inputs really helpful! 
You are right in that we are working in the dark until we can source some technical info. You have answered my question though - it's not gridlines....   Also, I wouldn't expect the results of aliasing (lack of lo pass filter) to be causing regularly spaced spot frequencies (plus they don't even look modulated?). It more has the look of some kind of beat between two frequencies closely related and I cannot even guess what's happening there. The I and Q signals arise from quadrature modulation but that comes from two identical frequencies locked together via 90 degree phase shift so not that!

Do we have anyone in the Group that has a contact in Xiegu? I heard (Bob Nagy?) that the spec  to for wasthe IQ output was be released around the time that the add-on 5" display was announced but I've seen no marketing info on a date for that.

I've only had my G90 for three weeks but I've been on hold in the Scottish Highlands for the last two - so really looking forward to the 're-union' tonight (ha!). I've built an endfed antenna as my first experience and now looking to build a doublet using kit from DC Commander.

Regards
Bob, MM0MMQ

Bob Bryce
 

Thanks bg8pd for this information. Do you also have any details on the release date for the technical spec for the IQ outputs?

Regards
Bob, MM0MMQ

"bg8pd
 

Hi Bob, I don’t have that information, We have to wait for the official news.
But,There are some drawings of GSOC revealed by the engineer of xiegu .
73 




------------------ Original ------------------
From: Bob Bryce <bob.bryce@...>
Date: Mon,Aug 19,2019 9:41 PM
To: XieguG90 <XieguG90@groups.io>
Subject: Re: [XieguG90] PC Panadapter using G90 I/Q output.

Thanks bg8pd for this information. Do you also have any details on the release date for the technical spec for the IQ outputs?

Regards
Bob, MM0MMQ

Bob Bryce
 

Thank you bg8pd - but the data may be corrupted??
If these files are jpegs then they do not open in my computer. The contents of the file look similar to type 'png', but that did not work either. Is it possible to upload in a different format??

Thank you
Bob, MM0MMQ

Chris Chatelain
 

Are those usb ports? What would that be used for?

 

Has anyone figured out how to plug the G90's I Q output into a typical laptop that has a single TRRS (tip, ring, ring, sleeve) connector for both stereo sound output and mono mic input? I've done a lot of searching on Amazon, eBay, etc. and I see few if any options for a USB sound interface that has a stereo line (or Mic) input.

Chris Chatelain
 

The Creative X-Fi HD has a line-in that has a left and a right channel. I'm going to give it a try. It's a usb device.

W5DXP
 

A $10 USB sound card dongle with stereo inputs is probably the way to go with a TRRS laptop.

"bg8pd
 

Hi Bob, MM0MMQ
  I just uploaded PDF file on my computer,try this one.
  73
------------------
Jian ,Luo  BG8PD
GuiYang city,P.R.CHina

 


------------------ Original ------------------
From: "Bob Bryce"<bob.bryce@...>;
Date: Tue, Aug 20, 2019 11:47 PM
To: "XieguG90"<XieguG90@groups.io>;
Subject: Re: [XieguG90] PC Panadapter using G90 I/Q output.

Thank you bg8pd - but the data may be corrupted??
If these files are jpegs then they do not open in my computer. The contents of the file look similar to type 'png', but that did not work either. Is it possible to upload in a different format??

Thank you
Bob, MM0MMQ

Bob Bryce
 

This one is blank as well......

"bg8pd
 




------------------ Original ------------------
From: Bob Bryce <bob.bryce@...>
Date: Wed,Aug 21,2019 5:54 PM
To: XieguG90 <XieguG90@groups.io>
Subject: Re: [XieguG90] PC Panadapter using G90 I/Q output.

This one is blank as well......

Bob Bryce
 

Hello Jian Luo
Many thanks for your efforts on sending these pictures!

best regards
Bob,
MM0MMQ