Observation 1807054: AZTECHSAT-1 (99833) Question for Fredy

Regarding Observation 1807054
Fredy - You scheduled this observation. Why? What is interesting about it and why is the audio presentation purple?
Tony KD1IK


Hi @tonyfromjupiter,

The last 10 days I’ve scheduled observations for satellites recently deployed from ISS. The goal is to receive the satellites (some of them don’t transmit regularly) and match these satellites with the published TLE (orbiting objects).

Until now we have managed to receive 4 of the 5, which we actively track, and have possible matches for 3 of them (4 in the next minutes as I’m working on checking some recent good observations of RADSAT-U).

This thread is a good opportunity to say a big thank you to all the station owners that contribute their stations for this process. After finishing with the identification (it will take some more days as objects are still close to each other) I’m going to recap the whole “event” and write an analysis about it.

Please let me know if there are any questions or something unclear.

EDIT I forgot to answer about the audio presentation, in the audio tab you can see the waveform of the uploaded audio in purple and the spectogram of it in grayscale under the waveform.


Thanks for the information, Fredy. If there is something I can do with either station 385 or 1168 to improve the results of your observations,
please let me know. Both stations are non-tracking/ fixed antennas.
385 has a turnstyle with a single reflector and 1168 has a 7-element Yagi fixed on the zenith (more or less - depending on the wind). No LNAs on either. Each has a Nooelec RTL-SDR with RPI3 processor located close to the antenna and powered with power-over-etherent.

Tony KD1IK


The better SNR (signal noise ratio) the better results you get from your stations. So anything to improve SNR would be more than welcome.

I’ve just checked and seen that you use the default gain for both of the stations, have you tried to change the RF gain on them? RF Gain is available in the advanced settings of satnogs-setup and for RTL-SDR it gets specific values that you can find by running rtl_test in command line.