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Re: TZ6RD operation..



----- Original Message -----
From: Jerry Pixton <jpixton@shentel.net>
To: Jeffrey Griffin <jeffrey.griffin@comcast.net>; <amsat-bb@AMSAT.Org>
Sent: Wednesday, August 20, 2003 12:43 PM
Subject: Re: [amsat-bb] TZ6RD operation..



> 1. We need to be using Full Doppler Tracking so that we can move way off
> frequency - like the low end of the band to adjust our transmitter. I
> notice in my setup that there are enough variables from day to day that
the
> offset moves around over maybe 5Khz so we need to be able to hear
> ourselves. Then we must be able to lock in that offset so we can tune back
> up the band and have the transmitter automatically follow us. This implies
> a modern radio that can track.

What??? Why complicate what it simple???
Let's do an example:
A Dx station dowlink is on 2401.373 MHz (MB+50).
(typical Tx frequency should be around 435.616 MHz)

A- Simplex
If Dx is working simplex, all the Dx chaser need to do is:
1. find his own downlink (by whatever mean used, as long as
    don't cause QRM on MB and users),
2. track the VFO's
3. tune the Dx station downlink
4. call.

B- Split mode
If the Dx station is working split (say 5 to 10 up), then
the Dx chaser, after done topic 1. to 3. mentioned above,
simply:
1. disable VFO tracking
2. shift TX frequency (minus 5 to 10 KHz, so from 435.611
    to 435.606 MHz for the given example)
3. call

The Dx chaser don't even need to care with doppler!!!
Just use the Rx VFO to tune his own downlnk (to check
if the Tx frequencly is clear, or if it's not triggering LEILA)
and then tune again the Dx downlink, and keep calling :0)

All mentioned above is valid for modern sat rigs, but's also
true for split emitter/receiver systems. Actually, it makes life
easier for those operators once it's not required to know
the EXACT Tx frequency.


> Another thought, many we need some reserved DX frequency.

I fully agree with this. Actually I already made a proposal in the past.
However I think any proposal will only have practical effects if it
will be endorsed by AMSAT's. Otherwise it will keep on being the
operators choice... (there is no continous pratice to establish a
reference frequency, like 14.260 were set for IOTA)

Those were my 2 cents of Euro ;0)

73 F.Costa, CT1EAT
www.qsl.net/ct1eat




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