[amsat-bb] Re: Doppler Tuning Convention Question (summary)
vk3jed at gmail.com
Tue Jun 1 14:36:40 PDT 2010
At 05:53 AM 6/2/2010, Michael Tondee wrote:
>was fun. Not so if I came upon a station who was using manual tuning
>while I was trying to let my computer do the work. I had to chase him
>all over the passband and often lost stations completely that way. I
>didn't fare much better with manual tuning. I guess I never really
>learned it like some of the "old hands" have.
I have had quite a bit of success with manual tuning on the SSB
birds. It does require a lot of attention, especially on V/U and
U/V. On mode A, it's fairly straightforward, though adjusting the
uplink on a radio that doesn't allow tuning on transmit is
tricky! One has to break their over into short segments of a few
seconds long and make the uplink adjustment in steps. :)
On V/U, I was using an FT-847 at a hamfest, which was easier,
provided I focused on keeping up with the Doppler. :D
> When I can finally afford the V/U unit for my new Flex and get back on
>linear birds it would be my hope that everyone who was in a base station
>setup would be using full doppler control via computer. It baffles me
>why anyone wouldn't, it makes life so much easier.
In my past, it was simply because I didn't have the right
radio(s). Now I have an FT-736R, and the first accessory I bought
for it was a CAT cable! :) I can even dedicate a computer to the job.
> I do understand why portable stations like Tim would not be using full
>doppler and I have no problem with that. I guess I just need to learn
>how to manually tune in that situation.
Yep, it can be fiddly, but rewarding.
>On 6/1/2010 12:14 PM, John Belstner wrote:
> > Thanks to everyone that responded.
> > For those that have been on the list for years this thread may be
> a dull rerun, but as a newbie, the information is useful.
> > > From everyones responses, it appears that indeed there are
> currently two conventions:
> > 1. Full Doppler CAT tuning
> > 2. Manually tuning the higher frequency while keeping the lower fixed
> > I know that operators have been successfully using convention #2
> for years so this is my lack of sat operating experience talking
> here, but just looking at the math it seems that it would be
> difficult for two stations with different velocity vectors to the
> satellite to communicate without at least one of them adjusting
> both TX and RX. I need to try this for myself I guess.
> > One thing I did notice is that when operating Full Doppler CAT
> tuning I was only able to successfully track other operators who
> were doing the same.
> > Cheers,
> > 73, John W9EN
> > DM13le
> > W9EN at AMSAT.ORG
> > _______________________________________________
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73 de VK3JED / VK3IRL
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