SO-50 & frequency stability as of late
I have been noticing some irregular shifts in SO-50's downlink frequency the past several days. I noticed it in the past but it's been a while since this occurred. Several others are reporting it as well.
At my AOS today (15:12 UTC, orbit # 62976), SatPC32 had predicted the downlink to be near 436.801 MHz, when in fact I was receiving the bird at 436.793. It proceeded to jump up to 436.795 at my TCA before making it's way down to 436.780 near my LOS.
This seems to be posing some issues for people using full computer control and also those who stick to pre-programmed memory channels to make frequency adjustments during a pass.
Considering this recent frequency instability, I would recommend you manually tune for the strongest downlink frequency. This would help eliminate some issues with stepping on stations engaged in existing QSO's. An alternative would be to try using RIT if you insist on computer control.
The old rule applies -- if you can't hear, don't transmit.
73 Clayton W5PFG
I noticed that and RIT "fixes" it.
73 Bob W7LRD
----- Original Message -----
From: "Clayton Coleman" kayakfishtx@gmail.com To: "AMSAT-BB" amsat-bb@amsat.org Sent: Monday, September 8, 2014 8:54:25 AM Subject: [amsat-bb] SO-50 & frequency stability as of late
I have been noticing some irregular shifts in SO-50's downlink frequency the past several days. I noticed it in the past but it's been a while since this occurred. Several others are reporting it as well.
At my AOS today (15:12 UTC, orbit # 62976), SatPC32 had predicted the downlink to be near 436.801 MHz, when in fact I was receiving the bird at 436.793. It proceeded to jump up to 436.795 at my TCA before making it's way down to 436.780 near my LOS.
This seems to be posing some issues for people using full computer control and also those who stick to pre-programmed memory channels to make frequency adjustments during a pass.
Considering this recent frequency instability, I would recommend you manually tune for the strongest downlink frequency. This would help eliminate some issues with stepping on stations engaged in existing QSO's. An alternative would be to try using RIT if you insist on computer control.
The old rule applies -- if you can't hear, don't transmit.
73 Clayton W5PFG _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Clayton,
I have been watching it shift 5-10 KHz or so on some passes, though 3-5 KHz is more common. Watching it with a DSP rig allows you to compensate.
The more interesting question is what, if anything, the uplink is doing? I got up for a 0200 L pass to experiment, and there was nobody else on. I thought I had it figured out, and suddenly the downlink shifted. Then, my uplink data seemed wrong, as if it also shifted. ;( Will try again the next time I have some insomnia.
73s,
Alan
WA4SCA
<-----Original Message----- <From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Clayton Coleman <Sent: Monday, September 08, 2014 10:54 AM <To: AMSAT-BB <Subject: [amsat-bb] SO-50 & frequency stability as of late < <I have been noticing some irregular shifts in SO-50's downlink <frequency the past several days. I noticed it in the past but it's <been a while since this occurred. Several others are reporting it as <well. < <At my AOS today (15:12 UTC, orbit # 62976), SatPC32 had predicted the <downlink to be near 436.801 MHz, when in fact I was receiving the bird <at 436.793. It proceeded to jump up to 436.795 at my TCA before <making it's way down to 436.780 near my LOS. < <This seems to be posing some issues for people using full computer <control and also those who stick to pre-programmed memory channels to <make frequency adjustments during a pass. < <Considering this recent frequency instability, I would recommend you <manually tune for the strongest downlink frequency. This would help <eliminate some issues with stepping on stations engaged in existing <QSO's. An alternative would be to try using RIT if you insist on <computer control. < <The old rule applies -- if you can't hear, don't transmit. < <73 <Clayton <W5PFG <_______________________________________________ <Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available <to all interested persons worldwide without requiring membership. Opinions expressed <are solely those of the author, and do not reflect the official views of AMSAT-NA. <Not an AMSAT-NA member? Join now to support the amateur satellite program! <Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (3)
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Alan -
Bob- W7LRD -
Clayton Coleman