Tracking a Radiosonde (weather balloon) with an RSP1A SDR and Rs41 Tracker (Sped Up 5x)

I thought I would have a go at receiving the telemetry from a weather balloon so I put up a 1/4 wave groundplane at about 20 feet. Added a masthead SPF5189z preamplifier and fed the signal into an RSP1a SDR via a 400-410 MHz bandpass filter. The output of the SDR is fed to VB audio cable and then into Rs41 Tracker.
Results are quite good as you can see from the video.
www.sdrplay.co...
vb-audio.com/C...
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m0ukd.com/calc...