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RE: FO29/FO20 blues

> My radio is a Yaesu FT-847. My antenna's are 21 and 42 element yagis
> for vhf,uhf and are on a mast that is rotated in azimuth and elevation. I
> am able to work UO-14 from horizon to horizon without any problem.

Sounds like have a quite capable station.

> When I track FO20 or FO29 I can receive on usb as I hear the digitalker
> and now with mode JA active on FO29 I hear people from time to time
> (although my S meter never move).
> However, when I try to transmit in the middle of the band (lsb on
> 145.95) I hear nothing on receive at 435.85.

> What am I doing wrong?

Doppler correction.
At the beginning of a high pass, the downlink will be almost 10 KHz higher
in frequency than a transponder frequency map will indicate.  It will drift
downward throughout the pass and end up almost 10 KHz lower in frequency
than the frequency map will indicate.  On a low elevation pass the change is
What I do is ballpark the frequencies (in the bottom of the transponder
passband) and switch my TX to CW and send a string of dahs and dial the
transmit frequency around to find myself.. Only takes a couple seconds.
Once I have it set, I switch the radio to inverse (or reverse) tracking and
dial up towards the middle of the passband where most of the activity is.
If any significant amount of time has lapsed, it will be necessary to tweek
the frequency again, but it will be close.

Jim Walls - K6CCC
Ofc:  626-302-8515    FAX:  626-302-9999
AMSAT member 32537 / WSWSS member 395

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