NOAA: Why starting in the middle of the transission?

Satellites & Observations
1

Hey.

If I look at the NOAA APT pictures: Why is it decoding in the middle of the signal?

https://network.satnogs.org/observations/105950/
https://network.satnogs.org/observations/105994/
https://network.satnogs.org/observations/105995/

The decoder cuts the half of the picture. Old TLE? Wrong time?

What is the problem?

2

Too weak signal. Being an analog “double modulation” (AM+FM), APT requires quite high SNR. When SNR is too low, the decoder will either not decode or decode noise if it is already locked.

3

Ok. The problem is: My DIY-Turnstile-preamp-combination seems to be not as good as other setups…

Hmmm…

4

Perhaps a pass that comes up to 60 deg in elevation; that might give better result :slight_smile: