Hi all,
I mentioned in my update post on REAL over a week ago that we have been having increased difficulty with commanding our satellite. I decided it was best to make this a separate topic so that the update thread won’t be taken over by it.
For most of the mission our ground station has required 400W+ to talk to REAL when it can hear the satellite just fine at its 1W transmit power. Our troubles really started after our main power amp failed and we were forced to replace it with a less powerful amp. To be clear, our trouble is on the transmit side of our ground station, not the receive side as we can generally hear REAL just fine. There are a few avenues of thought over why this disparity exists.
- REAL’s transceiver has worst receive performance than we measured here on the ground. This is very much a possibility, but we did do quite a bit of characterization of REAL’s transceiver after radio complications on our previous satellite.
- There are inefficiencies and/or misconfigurations in our GNURadio flowgraph. This has been our main investigative path, but anything we have tried has done little to improve commanding.
- Our ground station hardware is performing unknowingly below our expectations. We have only looked into this in a limited capacity as most of our previous testing has shown the hardware to be operating as expected. We do need to tune our new power amp, but we are working on that in the background.
I had been chatting with a member of the gr-satellites community but it looks like they weren’t able to find anything more than we did. So, now I am circling back to you all. If anyone is interested in helping out then I can upload our flowgraph with the code needed for a couple custom blocks.
Cheers,
Tyler, K7MSU
