[amsat-bb] PSAT-2/NO-104 status

[Tomáš Urbanec]

Hi all,

NO-104/PSAT2 status

The 2m/APRS side of the sat is still non operating for the unknown 
reasons. Any change or any packet heard would be welcomed.

The 435MHz side of the sat is still going strong. The PSK31 transponder 
is operating flawlessly with occasional activity seen over the US. If 
you are operating through transponder, you are asked to stay within 
400-1000Hz of downlink frequency. Lower you can interfere with the tlm 
beacons and higher you will be wiped off by the SSTV signal.

The orbit is elliptical with apogee position period approximately 34 days.

The 435.350MHz downlink frequency is temperature dependent a bit so best 
reception with any kind of SDR, where in waterfall you can see actual 
downlink freq. The greatest offset is seen after eclipse when sat is 
coldest. The downlink is operating in Sun only, it switches off entering 
the eclipse and switches on coming from eclipse or after 30minute timer.

The tlm beacons transmit every 4 minutes. The spectrum of the signal is 
narrow, so in SDR you can use just 2kHz bandwidth gaining SNR. Two 
minutes after tlm, the SSTV picture is transmitted in 4 minutes 
intervals also. For reception best bandwidth observed is around 9500Hz. 
Transmitted pictures are alternating prestored ones and pictures from 
camera memory stored on orbit.

Reception is possible on high passes with good omni antenna using the 
LNA in the quiet environment. But for the passes till horizon, 
directional antenna and LNA is needed.

We are still looking for any stations capable of regular downlink 
receptions with position between 40deg South and 40deg North. If you can 
make the receptions available in IQ format it would be greatly welcomed. 
Station capable of uplink in 29MHz to sat can be selected as commanding 
station and then can acquire pictures in real time or store them in 
sequence. So you can get pictures of your side of the globe, just 
contact us.

Further info and contacts can be found at

https://github.com/alpov/PSAT-2/blob/master/README.md

Best regards

Tomas OK2PNQ