Monday, June 11, 2018

DXVideo App

I've always struggled with Audio DSP and FFT software development.  But recently I came across some code libraries that help simplify this process.  IT's still not simple tho.

Currently my "DXFunnel" app can monitor all WSJT modes which output data via UDP from up to 8 WSJT's (including JTDX).   I use this presently to monitor 50.276 JT65, and 50.313 FT8, and 50.323 FT8.

"DXFunnel" can also monitor the output from my Skimmer Server which is based on Anan "Hermes" SDR.  It pushes spots of CW signals from 50.0 to 50.130 into DXfunnel.

The last area (aside from SSB :-) ) to monitor is TV Video Carriers.  I started creating an application named "DXVideo" which can monitor a 22 kHz Audio Spectrum, and map it to RF frequency.  

So for example I set a VFO or VRX (virtual RX) to 'digital' mode this presents 24 kHz of Audio via a Virtual Audio Cable (virtual sound card).    Actually I'm seeing about 22 kHz usable.  The software uses the 11 kHz point as the 'center frequency' and deviations +/- map in a graph and small datatable with their SNR (signal to noise ratio).

Since I didn't have a REAL video carrier I used a local baby monitor carrier to test, and I changed the VFO up and down to simulate a new video carrier just showing up.  This video demo's how it currently works.  

This is ONLY A TEST JIG to proof of concept the idea.  IT WORKS.  Now I have to clean up the app, add some nice options like CAT control/update of the RF freq, and things like controls to alter the graph size and such.

This application will then feed 'spots' of TV carriers between 49.739.0 and 49.761.0 to "DXFunnel" for human monitoring, and spotting to clusters.

GRANTED I'm fully aware that these TV Carriers will probably fade into history soon as the rest of the world migrates to HD TV.  But for now at least until they're all gone, I think it's a useful endeavor.

(Click on "Youtube" to watch larger version)

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