2018-05-25
Going full duplex with amateur satellites, part 13: receiving a linear satellite transponder / SO-50 without the preamp 4 months ago
This evening another try, this time without the preamp. And tried receiving a linear satellite transponder. This makes things even more complicated as I have to look at one display (gpredict) to have an idea where to aim the antenna and another display (gqrx) for the waterfall display. Maybe both can be on the same screen with a lot of resizing. The first pass I tried was a pass of the FO-29 satellite which has a linear transponder. It was not a very high pass so all reception was through a house. I did hear morse first, and later saw signs of USB signals in the passband. Signals were weak and noise was high. I was almost able to understand one callsign, a 9A.. callsign (Croatia). The other pass I tried was a pass of the SO-50 satellite which is a narrow FM satellite. Signals were weak for narrow FM so I had to keep turning the arrow antenna to get the polarisation right. I could hear spanish and english callsigns. I recorded the SO-50 pass and noted the audio looked very distorted in audacity. Maybe I can improve the audio somewhere in the chain and get things better.