Satellite Uplink Calibration

I finally had some time to ensure that my SatPC32 program was correctly calibrated to my Icom IC-9100 when using any of the three available linear transponder satellites.  While SatPC32 deals with doppler corrections (assuming the PC Clock is accurately set and the Keplerian Elements for the satellite are up to date), additional corrections are necessary to accommodate differences in published uplink/downlink satellite frequencies, and for any inaccuracies in the rig.  Optimally this uplink correction should be done independently for SSB and CW, but given time constraints, I decided to assume all my operation would be in the CW+ (CW enabled mode) based on the SSB Transponder data.

During the 18:26 to 18:46Z pass of AO-7, I used the SatPC32 “CAT” command then adjusted the “Upl Calib Hz” command until I heard my CW downlink roughly match my sidetone.  For my rig this was +4800 Hz (adjustment based on the default Doppler.sqf file that SAT32PC ships with).  The calibration data is saved by pressing the “Change/Store Data File” button, then the “Store Uplink Calibration” button.  The Sat32PC Doppler.sqf file was modified so that the AO-07 entry reads “AO-07,145950,432151.1,USB,LSB,REV,0,0,Mode B”

During the 19:04 to 19:18Z pass of FO-29, The uplink calibration turned out to be -100 Hz.  My Doppler.sqf file entry was adjusted to “FO-29,435850.45,145952.05,USB,LSB,REV,0,0”.  Note that the offsets were “435850.45,145952.15” prior to calibration, which makes sense.

Following calibration, I made a CW QSO with W1SJ in FN34 at 19:10Z using FO-29 on 435.840RX and 145.962TX.

During the next AO-7 pass (20:18 to 20:40Z), I worked NM3B from FN01 at 20:23Z (432.153TX/145.943RX) He was 599 and I was 579.  I also worked WC7V from DN45 at 20:31 (432.168TX/145.938RX) He was 569 and I received a 559.

AO-73 is in Beacon Mode until the satellite is in eclipse.  I was expecting that to happen during a pass around 10 PM local time (June 26 from 0207Z to 0219Z).  Unfortunately I was unable to hear my downlink as I tuned the uplink correction through +/- 20 KHz.  This was quite odd, as the last time I worked AO-73 it (and I) had a booming signal.  I double checked that I was somewhere around 435.140 up and 145.960 down (the midpoint of both the uplink and downlink).  The program appeared to be properly setup in terms of definitions.  Hearing nothing, I tuned down to 145.935, the approximate frequency of the telemetry beacon — I thought I heard it faintly (which is the case if the satellite is in transponder mode), but it was also toward the very end of the pass.  Unfortunately I can’t try again until Friday night.