[amsat-bb] Re: Satellite mode on IC-821H
ka8syx2003 at aol.com
Thu Jan 3 04:16:27 PST 2008
Hi, John --
Yes, fellow AMSAT members have been very helpful since I joined; this is by far the longest thread I've initiated or continued as generally I've been able to learn lots of stuff by just reading the mail that arrives in the inbox.
I also wanted to take a line to thank the several other ops who have weighed in to offer advice. Everyone seems to prefer SATPC32 over other applications - I have Scott Hather's Satscape installed on both desktop and laptop and like its presentation. Like SATPC32, it also has the ability to interface with a handful of transceivers and rotors with a Wisp DDE link to adjust Doppler and antennas, so I would like to try it first. I also used WinOrbit 3.6, but that was before I saw a demo of Satscape. I still use WinOrbit when I want a hard copy ephemeris to take outside with me (so far I've only operated on satellites portable) I still will look at SATPC32 and likely will try it out too.
John, I certainly didn't mean to imply anything negative regarding our conversation about adjusting for doppler; When I used separate transceivers I always tuned the rig on the higher frequency and left the lower one alone, but like you experienced the problem of greater divergence between up and downlink as a QSO progressed. Every time I think about doppler correction I think of the "one true rule" paper and still cannot wrap my brain around it completely. It may be because I have never watched another op do it all during a pass -- I've never enjoyed or even listened to a live QSO on a HEO bird, only
.wav/MP3 files listened to on the internet.
So, thanks, everyone. I have a week left before my family returns home -- keep your fingers crossed, maybe I'll be able to pull it all together and see what happens by then.
V/r and 73,
Jacksonville, FL, EM90ee
From: John Henderson <jah at ec.rr.com>
To: Ka8syx2003 at aol.com
Sent: Tue, 1 Jan 2008 7:29 pm
Subject: RE: [amsat-bb] Satellite mode on IC-821H
Glad to help…that’s what AMSAT’s about! Surprised you were able to dope anything out of that but I’m glad you did.
The reason some of us don’t track but one freq is that the freq in the Doppler.sqf files are the actual xmit/rec freq from the sat. Even tho we put in lat/lon in SATPC32 ( BTW it’s the best) the Doppler correction algorithms do not correct them sufficiently to always be right for your QTH. You will usually find they are off by 2 or 3 khz and you adjust them in the .sqf file til you get it right for your QTH. I choose just to make the xmit zero and work on the receive. You might post a question to the BB and get a better answer or find that I am not doing it the best way. It works for me and I have about all the sats corrected for my location.
When you get it up and running turn on the C+ and see how close you are to being on freq. Turn the C+ off and turn by hand and not the difference between the radio and SATPC32 freq tracking. Subtract those and you’ve got the delta for correction.
I live on the coast of NC and our locations are similar for the south to north or viv coastal passes that are long and the doppler rate is high in the middle of the pass; that’s where they really are off the most.
I am retired and the kids are gone and I really enjoy the sats and computers, etc. I have been a ham since late 50’s in high school and I can say this is the most enjoyable part of ham radio I have found and all the folks on the board are really helpful and most of them ( with some exceptions including yours truly) are pretty knowledgeable.
Let me know if have any more ?? about the 821H. It’s a good solid rig. I’ll be listening for you
John Henderson N4NAB
212 Bayside Drive
Cape Carteret, NC 28584
n4nab at amsat.org
More new features than ever. Check out the new AOL Mail ! - http://webmail.aol.com
More information about the AMSAT-BB