[amsat-bb] Re: Offset Correction for CW Beacons in SatPC32
al7cr at punakea.com
Sat Dec 2 08:40:20 PST 2006
Thank you very much for your description. The procedure and the
difference between the two functions is now quite clear.
Erich Eichmann wrote:
> 1. to calibrate your 2 data lines for each SSB sat for SSB and CW do
> the following (separately for the SSB and CW entry):
> While the satellite is audible calibrate the uplink frequency until you hear
> your own voice or CW signal with the best audio pitch. To fine tune the
> uplink frequency use the "Upl. Calibr." controls in menu CAT (these controls
> leave the downlink frequency unchanged, so, they change the offset between
> downlink and uplink frequency).
> Then click the button "Change/Store Data File". In the menu that opens click
> on "Store ...Uplink Calibration". This function saves the new offset and at
> next program start you should hear your own signal with the right audio
> pitch or very close to it.
> Recently there was a discussion whether to use the button "Change/Store
> .. TX/RX frequency data" to save the calibration. The purpose of that
> function is another one, however, see below.
> The calibration procedure should be done with each SSB satellite, because
> there are hardware depending frequency deviations between the single radios.
> So, the frequencies that come with the program can't be optimized for each
> radio. Between my IC-821H and IC-910H, i.e., is a deviation of about 1 KHz.
> The mode entry in Doppler.SQF (USB, LSB, CW) can be changed only manually
> with Notepad, of course.
> To start CAT tuning immediately on the beacon frequency of a satellite, i.e.
> FO-29, do the following (after you executed the procedure above 1):
> While the satellite is audible tune the radio to the satellite's beacon
> signal. That can be done with the VFO knob.
> In menu "CAT" click the button "Change/Store Data File" and in the menu that
> opens click on "Change/Store RX/TX Freq. Data".
> That will save the new uplink AND downlink frequencies (after eliminating
> the actual Doppler shifts, of course) but leaves the offset unchanged. To
> operate over the satellite you only need to tune off the beacon frequency to
> an unused frequency.
> (This feature was very helpful with the AO-40 S-band beacon. It allowed to
> easily find the own downlink signal inspite of the daily temperature changes
> of the outdoor downconverter L.O.)
> 3.There is a detailed description of these functions in the manual in the
> section regarding menu CAT.
> 73s, Erich, DK1TB
> ----- Original Message -----
> From: "Dean Shutt" <al7cr at amsat.org>
> To: <erich.eichmann at t-online.de>
> Cc: <amsat-bb at amsat.org>
> Sent: Friday, December 01, 2006 8:56 PM
> Subject: [amsat-bb] Offset Correction for CW Beacons in SatPC32
>> Further to a recent question, it appears that I must change the
>> doppler.sqf file to calibrate a cw beacon rather than use the
>> "change/store data file" button. Is this correct? I have a seperate
>> line for each SSB sat that tunes the beacon frequency in CW mode and was
>> attempting to adjust for the offsets in my system.
>> Thanks for the help.
>> 73 de Dean, AL7CR
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