[amsat-bb] Re: SSB Operation on the Satellites

David Palmer KB5WIA kb5wia at amsat.org
Thu Jun 9 10:19:27 PDT 2011

Jerry's correct.  If you only adjust your transmit frequency, such
that your receive frequency appears to stay the same -- then you're
automatically correcting for your own downlink doppler, but not for
anyone elses.  Other hams in the footprint will still have to chase
you.  The only way to stick with the "one true rule" is to adjust
*both* uplink and downlink during the pass.

That being said, adjusting the higher (UHF) transmit frequency on
VO-52 and AO-07 only (ie. manual control) will get you pretty close,
and you won't drift a whole lot.  I hear plenty of hams doing this, as
long as there are just one or a two QSO's going on, they don't drift
into each other very often.

73 de Dave KB5WIA / CM88
SatPC32 with 2xFT817ND

On Thu, Jun 9, 2011 at 7:35 AM,  <n0jy at lavabit.com> wrote:
> OK my brain may be playing tricks, but if you vary only your transmit
> frequency such that you always hear yourself on the same downlink
> frequency, isn't it true that the other station may not necessarily be
> hearing you on the same downlink frequency and is chasing you anyway?
> Your doppler is +5kHz (for example) on the receive, the bird is just about
> to pass overhead of me though so my receive ferquency goes rapidly from
> +2kHz to -5kHz, your transmit tuning has no relation at all to what
> frequency I am listening on.  Then the bird goes past you and you suddenly
> switch down 5kHz, so I have to follow you on my receive.
> Or am I nuts?  (Quite possible, come see where I work and you will
> understand!)
> Jerry
>> I always varied the transmit.
>> This way the person I'm talking to as well as any other listeners are
>> all on the same freq listening.

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