I made my first QSOs via LilacSat-2's SDR linear transponder on two passes this morning - both with W5PFG - on the 1112Z and 1248Z passes.

The transponder sounds quite good, though it seems somewhat less sensitive than other linear transponders. Running 25 watts to an Alaskan Arrow (with the top section removed - 8 elements on 70 cm and 3 elements on 2 m), my signal was weaker than on FO-29, AO-73, or any of the XW-2s. Telemetry bursts also occasionally interrupt transmissions on the transponder, but they are very short and not of much consequence.

I was manually tuning since I operate portable without a computer. Keeping up with the nearly doubled Doppler shift compared to a inverting transponder is a challenge. I was leaving my uplink frequency fixed and tuning the receive as per convention for manual tuning and had to continuously tune to keep my downlink within the receiver's passband near TCA. On the first pass, W5PFG answered my CQ, though on the second pass, I tuned around to answer his CQ after receiving no responses to my own. Tuning around the passband manually reminds me of playing Halo back in the dorms at Michigan State and subbing in for another player who used the non-inverted controls (I have always played video games using the flight simulator style of down=up).

Other stations were heard on the pass using LSB up and LSB down. That will work, of course, but goes against convention, which is to always receive in USB. If you choose LSB/LSB, you'll likely receive fewer responses to your CQs.

73,

Paul, N8HM