Apologies for typo in callsign, WA6LRL should be WA6RLR.
- Umesh
On Thursday, June 27, 2019, 7:25:08 PM PDT, k6vug@sbcglobal.net k6vug@sbcglobal.net wrote:
FYI - Lastly, on general principle, I recorded a couple of short clips illustrating said calibrating procedure for SSB sats, in case anyone is interested.
Calibrating the XW-2C pass and having a nice QSO with WA6LRL: https://drive.google.com/open?id=1Kio_Rb-KCNTNr_N5ppZWa4MV6wEe9ltd
Calibrating the XW-2B pass and moving around the pass band: https://drive.google.com/open?id=1lNMD7fjVV3R26r7p1w8y2maeEaAzGF7p
The setup includes a IC-7000 for the uplink, RTL-SDR for the downlink, HRD provides Doppler correction for the radios and drives a fixed elevation azimuth rotator.
The tuning process goes like so : - First I wait until can listen the CW beacon - Then I switch to the transponder frequency pair in HRD Satellite - And while briefly transmitting a steady 800 Hz tone via a simple 555 circuit, I calibrate the Rx offset in SDR# for about 800Hz. - After that, I can move the Rx across the pass band while HRD does the Doppler trick.
Its like working HF, it almost takes the challenge out of working SSB sats ! Calibrating via SatPC32 would be very similar. The clips show panning across the entire pass band of +/- 10 khz, without having to recalibrate during the pass. Also, the calibration tends to be a little different for each satellite. 73! Umesh k6vug
( the pulsing sounds in the second clip is some cross modulation noise and nothing like the Contact movie ! :)
On Sunday, June 23, 2019, 10:07:07 PM PDT, k6vug@sbcglobal.net k6vug@sbcglobal.net wrote:
To add a bit of personal experience - calibrating the uplink forced both stations "walk" the band during the QSO. Eventually, realized that adjusting the downlink instead was a better choice, and has been smooth sailing since.
Technically speaking, the calibration of the downlink takes care of abnormalities in the entire chain and that lets the program (SatPC32 etc.) ensure that the uplink is spot-on any time you pan the downlink, during the pass.
(Disclaimer - while there are a different schools of thought, the above is solely based on personal observations, failures and successes. Individual mileage may vary.) 73! Umesh, k6vug
On Sunday, June 23, 2019, 4:49:12 PM PDT, Bob via AMSAT-BB amsat-bb@amsat.org wrote:
Hi,
The manual is your friend. The secret sauce is to adjust your uplink on the CAT menu until you can hear yourself, then save the uplink calibration. Trying to tune the radio knob caused both the uplink and downlink to change and is not how you calibrate things, but is exactly the behavior you want (manually tuning to find someone to call, and being spot on with your downlink too. I do feel sorry for the folks, hundreds (thousands?), vainly sending dots/dashes during Field Day attempting to find themselves. The secret sauce is to do that before Field Day. With the exception of AO-7 which was unusually far off, all the other dozen+ satellites were within a couple hundred hertz or less of the calibration values I use at home on my 9100 (in a fairly stable thermal environment).
Good luck, but rest assured that SatPC32 works great controlling Doppler.
73, Bob, WB4SON
On Sun, Jun 23, 2019 at 5:49 PM Bruce via AMSAT-BB amsat-bb@amsat.org wrote:
I bought a Yaesu G5500 to use during field day this year, we got tired of the arm strong rotor. This is the first time I have used SATPC32 for anything more than AOS-LOS predictions. I still moved the rotor by hand. Have not been able to get the Yaesu cable built to have the LVB tracker control the rotor. May work on that for next year.
Used the ICOM IC-9100 and a laptop this year. It worked great to set the frequency for the FM satellites but was horrible for any SSB satellite. I can find myself with the computer turned off. When I tried to use Satpc32, it would jump to somewhere in the passband and no matter how i tried to adjust the radio to find myself, satpc32 had a mind of its own. So, never made an SSB contact. Of course it is more fun to do this during field day with everyone watching.
So what is the secret for making Satpc32 see where you have found the sweet spot on the up and down link when you click CAT control instead of doing what it wants? I would have thought it would read the settings from the radio and go from there. After all, it takes me a few seconds to find myself and really easier to adjust for Doppler manually. I wanted to give the automated feature a go for those watching.
73...bruce
--
Bruce Paige, KK5DO
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_______________________________________________ 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: https://www.amsat.org/mailman/listinfo/amsat-bb