The latest edition of "The ARRL Satellite Handbook" contradicts earlier versions, which suggested the same approach that Drew has here (i.e., always Doppler-tune the higher frequency) in favor of "parking" the uplink frequency and Doppler-tuning the downlink (see the section "Finding Yourself ... and Others," which begins on page 5-13 of the handbook). It occurs to me that, in general, that is the worst approach to take - although I admit to only knowing enough about all of this to be more dangerous than not.
Before I added computer-aided Doppler tuning to my station, I took Francesco's approach and always tried to stay at the same downlink frequency, Doppler-tuning the uplink regardless of whether it was the higher frequency. In reality, my approach is only inconsistent with Drew's ONLY on FO-29 because, on AO-7 (when in Mode B) and VO-52 (always in Mode B), the uplink IS the higher frequency.
The reason I believe the 2008 edition of "The ARRL Satellite Handbook" offers the worst approach has two elements:
1 - the "slipping" on the downlink that Francesco alludes to in his post, and
2 - the use of VO-52 as the "example satellite" for the description of how to find one's signal. The exercise directs readers to Doppler-tune the lower of the two frequencies to find themselves on the satellite.
Later today, I will try the "always tune the higher frequency" rule on FO-29, which I admittedly have not every tried. I'm looking forward to learning how that works for me since the higher frequency on that satelite is the downlink.
73 to all,
Tim - N3TL
-------------- Original message from Fabiano Moser fabianomoser@gmail.com: --------------
Dear friends,
We know that some Satellite Operators use diferent system to doppler control.
For Linear Transponder
- Adjust uplink and downlink automatic by CAT? (Not always woks, some times
I´m up or down from the computer adjust) 2) Adjust uplink and downlink manual 3) Keep Uplink fixed and adjust only the Downlink frequency.
What is the more indicate method to use? FT-847 have knob to adjust Uplink without change downlink VFO, and I´m using it to keep my voice in downlink at same downlink much I can.
But I know some operators use fixed uplink.
How you do?
-- 73 Fabiano Moser CR7/PY5RX ARISS-PORTUGAL (Amateur Radio on the International Space Station) Representative at Teleconference and Portugal Telebridge Coordinator. AMRAD/AMSAT-CT http://www.amrad.pt/ariss.php
"There is no great talent without great will. (Honoré de Balzac)" _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb