brainwagon "There is much pleasure in useless knowledge." — Bertrand Russell

28Jan/080

Another try at LO-19 on some new equipment

Well, I couldn't stand it anymore. I picked up a new Yaesu FT-817ND to expand my capabilities. It's a neat little radio, and tunes all the way from 160m up to 70cm, and has SSB, AM and CW capabilities. Neat.

My idea was to try to listen to AO-16: I figured that the Doppler would be easier to handle by hand. I didn't have much luck though, so I decided to try to write a simple program that interfaced to my Python code to do automatic Doppler correction. Basically, it tunes the radio every couple of seconds according to where it predicts the downlink frequency to be.

Well, it didn't work that well on the next pass (I'll try again), but I noted that LO-19 was coming up, and it's very loud, so I modified the script to track its frequency, and got the following recording:

Spectrogram of the audio…

LO-19’s Morse Telemetry Beacon

If you look or listen carefully, you can hear where the receiver retunes (it makes an annoying little weedle, and you can see the frequency jump in the middle of a dash in several places). But overall, the morse stays pretty darn stable in frequency.

Neat for a few minutes of scripting.

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