Observation 306365: UNISAT-6 (40012) out of frequency

Satellites & Observations Observations
#1

Strange behaviour in Observation 306365 at my station. At beginning of the pass, the signal is received at correct frequency, then it jumps out by about 20kHz.

Also the following Observation 307546 of PICSAT seems out by 10kHz.

Is it something related to SW? I may have a look in the logs.

Alberto

#2

Hey @iq1ry,

For 306365 is indeed strange, I haven’t seen something like that. What setup do you have? Which sdr?

It could be software or a combination of software and hardware.

For 307546, this is not PICSAT, as PICSAT hasn’t transmitted for months.

#3

I see occasional slant on UNISAT-6 that may suggest TX drift; however, your problem seems like frequency error in the SDR dongle. See for example obs 306338

#4

I also think it is a problem on my side. From the log (/var/log/syslog) there is nothing strange around that time. Is there another place where I can find something?
BTW, dongle is a NooElec (that with aluminum case).

Tnx!

#5

Two other things you can try:

  1. If you have access to other sdr, try it in order to make sure if it is an sdr problem or sth else.
  2. During an observation, try to check cpu of the rpi (? do you use raspberry pi, which version?). To check cpu you can ssh in your rpi and run htop. (If it is not installed then run sudo apt-get install htop).