[amsat-bb] Re: A051
n5td at vvm.com
Sat Aug 25 10:30:44 PDT 2007
I hope this comment will help someone just learning to work
the sats. While saying "always correct the higher of the two
frequencies" may be good advice-- in modes where the lower
of the two frequencies are either 2-meters or HF, but it won't
work too well when you get up into using Mode-L or Mode-S.
For the higher frequencies in Satellite communications, throw that
notion out the window!
Dopplers vary so much on BOTH frequencies in those cases,
that you won't be successful by only correcting the higher frequency.
I know what an advantage "computer-controlled" Doppler correction
can be if everything is correct, but I've also used pre-programmed
"channel techniques" in several of my satellite radios to work the FM
mode satellites, supplementing with fine corrections manually to
optimize. (I have an FT-847, two IC-821H's, an IC-970, and an
IC-910H, the later of the two having 1.2 GHz.)
I've made some fine L/U contacts on AO-51 lately using two 1.2GHz
uplink systems-- one, an array of four 35-element Yagis phased together
for low elevation angles, and two, a pair of 24-element Yagis phased
together with az/el control.
Do not be discouraged by people indication that "manual control"
just doesn't work. It may be quite a challenge, but it works very
well! Enjoy the SATS...
----- Original Message -----
From: "Bruce" <KK5DO at amsat.org>
To: "Roger Kolakowski" <rogerkola at aol.com>; "Marc Vermeersch"
<mvermeer at skynet.be>; "'AMSAT-BB'" <amsat-bb at amsat.org>
Sent: Friday, August 24, 2007 6:39 PM
Subject: [amsat-bb] Re: A051
> if people would not snip the part out of the original post, you would have
> seen in my next sentence that I said in the absence of computer control
> you always correct the higher of the two frequencies as that is the
> frequency affected most by doppler. It does not matter if that frequency
> is the tx or the rx, always the higher of the two.
> rr on my daughter...boys, school, clothes and cd's take her money hihi
> she went off to university last week...maybe if she gets a fully automated
> station at school we would hear from her more often.
> -----Original Message-----
> From: "Roger Kolakowski" <rogerkola at aol.com>
> Subj: Re: [amsat-bb] Re: A051
> Date: Fri Aug 24, 2007 6:03 pm
> Size: 1K
> To: "Marc Vermeersch" <mvermeer at skynet.be>, "'Bruce'" <KK5DO at amsat.org>,
> "'AMSAT-BB'" <amsat-bb at amsat.org>
> Bruce (a very influential and integral part of AMSAT) projected:
>> As doppler affects
>> both frequencies, they should both be corrected using computer control
> But computer control may not be available in DX, mobile, remote, battery
> power, "minimalist" or "emergency" situations.
> Computer control is an advancement, it should not keep people off the
> satellites. If everyone spouts "computer control" you will never give a
> "newbie" the satellite bug.
> I have a QSL card from Bruce's teen age daughter...Bruce, do you think
> as a bona fide Ham Radio operator, has the personal finances available,
> assuming she is saving for college, to put together a computer controlled
> SSB satellite station? Why should she be kept off the linear birds because
> she can only afford an inexpensive 435 SSB/CW rig and a preamp,
> downconverter for 2 meters to 10? (BTW my 2 kids are licensed also but
> are 28 and 24 respectively.)
> I believe there should be correction, but it does not HAVE to be "computer
> controlled," it has to be on a best effort basis.
> Roger (first Satellite contact on RS-6 & multi contacts keying an FM rig)
> ----- Original Message -----
> From: "Marc Vermeersch" <mvermeer at skynet.be>
> To: "'Bruce'" <KK5DO at amsat.org>; "'AMSAT-BB'" <amsat-bb at amsat.org>
> Sent: Friday, August 24, 2007 7:36 AM
> Subject: [amsat-bb] Re: A051
>> > this method of correcting for doppler is an incorrect practice. It
>> > might
>> > be fine if you and your buddy are the only two on the satellite. also,
>> > notice you say 'you perfer', not the correct method. As doppler affects
>> > both frequencies, they should both be corrected using computer control.
>> Meaning: Keep the frequency at the satellite constant... Right?
>> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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