SDR# IQ from Sound Card bandwidth

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Remon
Posts: 47
Joined: Fri Jun 22, 2018 2:49 am

SDR# IQ from Sound Card bandwidth

Post by Remon » Tue Jun 26, 2018 11:44 pm

I am using SDR# for decoding Tetra with a plugin. Now i want to monitor and decode another Tetra frequency simultaniously. What I tried:

Installed AUX VFO plugin and tuned to the 2nd frequency
Set the output to VB-Audio virtual audio cable
Opened a second screen of SDR# and choose for IQ from Sound Card
Input is the VB-Audio virtual audio cable

Result:

I hear and see the Tetra signal. The problem is that (when in IQ from Sound Card mode) the bandwidth is limited to 29 kHz, while the Tetra decoding plugin needs at least 48 kHz to decode the signal.

I tried to change the virtual soundcard sample rate from 48000 to 96000 hz with no succes. The IQ from soundcard mode in SDR# is limited to use as a VLF receiver.

Is it possible to modify this, or are there standalone Tetra decoders for Windows with sound input that I can use to monitor a second Tetra frequency?

rtlsdrblog
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Joined: Mon Nov 19, 2012 11:54 pm

Re: SDR# IQ from Sound Card bandwidth

Post by rtlsdrblog » Wed Jun 27, 2018 12:35 am

Try adjusting the sample rate of the sound card in Windows settings.

If that doesn't work try the original Windows Telive port, information here https://www.rtl-sdr.com/wintelive-tutor ... mentation/. It's significantly more complex, but I think it's possible to get multiple channels with it.

Remon
Posts: 47
Joined: Fri Jun 22, 2018 2:49 am

Re: SDR# IQ from Sound Card bandwidth

Post by Remon » Wed Jun 27, 2018 1:04 am

I already tried that in my soundcard settings. And I can't get the Telive port to work with a (virtual) audio cable input. It is expecting samples from a SDR over network.

Even static noise looks like this:

Image

Maybe I need to buy an extra RTL-TCP stick. :P

Remon
Posts: 47
Joined: Fri Jun 22, 2018 2:49 am

Re: SDR# IQ from Sound Card bandwidth

Post by Remon » Thu Jun 28, 2018 9:33 pm

This topic can be closed. I'm trying to set it up with a different approach and will open a new topic.

Remon
Posts: 47
Joined: Fri Jun 22, 2018 2:49 am

Re: SDR# IQ from Sound Card bandwidth

Post by Remon » Fri Jun 29, 2018 11:05 pm

I solved the problem with a different approach: I found a piece of software that's in between SDR# and my RTL_TCP server. In fact it's a splitter that connects to the server and adds an extra listen only stream on another port. I can open 2 instances of SDR# this way.

rtlsdrblog
Site Admin
Posts: 2474
Joined: Mon Nov 19, 2012 11:54 pm

Re: SDR# IQ from Sound Card bandwidth

Post by rtlsdrblog » Sun Jul 01, 2018 11:52 am

Nice one. What's the splitter software called?

Remon
Posts: 47
Joined: Fri Jun 22, 2018 2:49 am

Re: SDR# IQ from Sound Card bandwidth

Post by Remon » Sun Jul 01, 2018 12:20 pm


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