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Re: HT Satellite Tracking



On Tue, 31 Oct, Chris wrote about sat object tracking on the APRS freq:

> All they had to do change to APRS mode, receive Satellite tracking data,
> change back to Satellite mode, try acquiring the bird, and change back to
> APRS mode to view additional tracking info if they where not successful.
> A strong argument for satellite tracking software running on a different
> device IMHO.

Agree completely for the satellite operator.  But this "service" is
only intended to alert mobiles or handhelds already on APRS channel of an
"opportunity" to work a bird from his mobile whip or handheld.... not as a
solution for everyone who does not need it.

> Perhaps your program could occasionally broadcast updated keps to be
> captured by such devices.

It does.  APRSdata is configured to transmit a NASA one-line KEP packet
say about once an hour.  Or on demand.  THis updates anyone permamently
monitoring 144.39 with new keps once a day.  Or a 2 hour commuter will
have collected a new set about once every 10 days.  More than adequate for
non maneuvering birds.  We could have it do SHUTTLE or other piloted
birds more often after each new set of elements.

The format of the APRS one-line element packet uses the unique identifier
of "{K1" to identify the start of the One-Line-Element data.  In a packet,
this looks like this:

   FROM>TOCALL,DIGI1,etc:{K1............................

where the .....'s are the NASA one-line-format.

de WB4APR, Bob

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