Re: Airspy Mini Direwolf APRS IGate RPi

David Ranch

Hello Nick,

Few things:

   1. What's the "ADEVICE" in your direwolf.conf?  It should be "ADEVICE stdin null"

   2. You said you're using the "rx_fm" command which seems to be a tool using the Soapy API.  For the Airspy, you should be using "airspy_rx" which is apart of the airspy-host packge : .  If you want to continue using the other tool, you probably should send an email to that group.

   3. When using the airspy_rx tool and depending on your computer and the USB controllers on it, don't use USB packing in the airspy_rx tool

   4. Direwolf like all digital mode programs are sensitive to levels so you might try sending your signals to a file and analyses with tools like Audacity first to make sure things look sane.


On 04/26/2020 10:31 PM, Nick KC9VGV via wrote:
Hi all,

I’ve been working on getting a Receive Only IGate setup.  I have been using an Generic R820 RTL-SDR Up to this point.  Due to to frequency drift and other factors I thought it would be better to upgrade the receiver to the Airspy Mini, in doing this I’ve run into quite a few issues.
My Setup Raspberry Pi 3B+ / Pi 4
I compiled the rx_tools along with rx_fm.
I can run gqrx and within it I can decode the AFSK 1200 Packets with the builtin decoder.  My problem comes in when I try to use rx_fm to pipe into Direwolf.  It seems like it is working but the only packets i will see roll across the screen are ones from when I beacon from a station that is only a few feet away.  When I’m in gqrx I can see so many more psckets.  I’ve tried to double check my setting to see if I’m setting them both the same.  Here is the command I’m using.
rx_fm -M nfm -f 144.390 -d driver=airspy -w 200k -s 3000000 -r 32k -g LNA=8,VGA=6,MIX=8 - | direwolf-c /home/pi/sdr.conf -r 24000 -D 1 -B 1200 -

Anyone see anything I’m missing?

Again it will record packets if I am right near there transmitter but I’m not seeing any other stations yet when I quickly go back over in gqrx I can hear quite a few stations coming in.

-  Nick

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