Hello Everyone, I am frantically rushing to get GNU Radio to 'play nice' with foxtelem. I'm running all linux here. I'm hoping someone can maybe throw me a few pointers on getting the fox telem software to work with external SDR applications. I'm attempting to pipe signals from GNU Radio in three ways, all met with failure:
First is by running an FM receiver flowgraph and then trying to pipe the audio out via a Linux FIFO using the 'Wav File Sink' block in GR. I point the SDR flowgraph to my pipe, and then I point the FoxTelem software to the same pipe and fire the programs up. I've successfully used this method in the past to feed a sound streaming application that "thinks" is reading from a standard wav file, but is actually the GR flowgraph audio output. GNU Radio seems to run for a second or two (probably the amount of time it takes to fill the buffer) then the Fox Telem Software crashes with exceptions:
'javax.sound.sampled.UnsupportedAudioFileException: could not get the audio input stream from input file.'
In gnu radio I'm using the wav file sink with a single port and sample rate of 48k and 16bits. This "appears" to match what FoxTelem is expecting, but I'm getting the crashes.
An alternative method I'm attempting is to use a standard audio sink in gnuradio (I can hear the audio on my laptop speakers) and then try to pipe that into the fox sw with a virtual audio cable. I'm attempting to use JACK and qjackctl, but I have little experience with this and so far have failed to get it to do anything other than listen to the soundcard mic and line in ports. If someone knows of a simple to use Virtual Audio Cable for Linux so that I can pipe the audio via the sound card that would be great and I can give that a go.
The third method I'm trying to get working is by placing the fox sw in IQ mode and again attempting to use a 'wave file source' in foxtelem pointed at a FIFO to pipe the IQ data from GNU radio into foxtelem. again I get the exception mentioned above. This would be the preferred method in my case over the audio piping. If someone has any experience with this that would be great. For those familiar with GNU Radio I'm taking the complex stream (250ksps), reesampling to 192ksps, converting to float, then taking the real and complex streams and feeding them into a 'Wav file sink' with TWO ports pointed at the fifo, again with 16 bit depth and set to 192ksps. Foxtelem is looking for a wav file at 192ksps. I'm hoping the two port file sink allows I data on the right channel (in0) and Q data on the left channel (in1).
Any and all pointers would be welcome.
Thanks, Zach, KJ4QLP