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Re: One True Rule Doppler tuning questions



Jim,

Noticed the same problem myself. Started out as a program to make
SSB coms easier on FO-29 using an IC-706. Turns out things change
so fast on LEOs and passes are so short that the "test, tweak, test"
cycles were very frustrating.

I'm using pretty much the same algorithm that Art N3OY has implemented,
with my implementation written in Python. I chose PREDICT as my compute
engine.

AO-40 capability is on the way. Completed fab on dish mount and shot
parts w/ primer yesterday. Hope to start setting up next week so, 
testing of the SW should be much easier.

I'd like to collaborate on our work but, don't expect to be available
until this winter. Won't be that long though, winters come early here
and last a long time. Great for SW development.

73,

 Thu, Jul 17, 2003 at 10:26:01PM -0700, Jim Cottle wrote:
> Hello All,
>   I am authoring a program to implement the one true rule for the
> combination of NOVA and the IC910 since there are not really ones usable to
> me. This is going to be a great program.
>   I have a problem though. When I adjust to NOVA's downlink with doppler
> correction, then, with frequencies locked at the satellite, go to the
> predicted transmit frequency, I do not find my station. I always have a
> realtively unpredictable offset to account for. I cannot quite figure out
> what i am doing wrong.  COuld someone help me with a step by step procedure
> to check myself? Here is what I am doing:
> 1. Find the Beacon with the radio
> 2. enter the proper LO into NOVA, so that the actual predicted downlink
> frequency matches the rig with doppler correction and 2401.323 entered at
> the satellite. this turns out to be about 2255.999 990 for my UEK-3000.
> 3. With frequencies locked at the satellite, I match 2401.323 to the same
> calculated MB value on the Uplink side (either U-band or L1-band). I thus
> move down from the top of the L1 band by the same amount as moving up on the
> S2 band.
>    After doing this shouldn't I get predicted frequencies from NOVA that,
> when i tune my uplink frequency to, I should hear my station on the
> downlink? (assuming I now move off the MB frequency onto a MB+20 value or
> so?)
> What am I missing? some sort of offset correction for inaccuracy?
> Jim
> AC4EA
> ac4ea@****.net
> ac4ea@*****.org
 
-snip

-- 
Joe Ennis - w7net
Whitefish, Montana
http://www.whiskey7.net/
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