[amsat-bb] LilacSat-2 Linear Transponder over North America 13-Jul

Paul Stoetzer n8hm at arrl.net
Wed Jul 13 13:12:18 UTC 2016

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

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.


Paul, N8HM

More information about the AMSAT-BB mailing list