[aprssig] APRS for a "ocean buoy"
Stephen H. Smith
wa8lmf2 at aol.com
Mon Jan 8 22:59:35 CST 2007
jimlux at earthlink.net wrote:
> An acquaintance asked if there was decent APRS coverage along the
> coast of California, say out to 10-20 mi from the shoreline. The
> transmitter would be pretty close to sea level (on a kayak, for
> instance). 30m HF is an option, but there was some uncertainty about
> what sort of antenna would be possible for that.
> The alternatives are conventional satellite tracking (Argos, Orbcomm,
> Inmarsat D+)
> Jim, W6RMK
> aprssig mailing list
> aprssig at lists.tapr.org
20 miles out with the antenna effectively on the ground (not on a boat's
mast), you probably won't do anything on VHF, unless you are off the
shore of the populated parts of CA with nearby mountaintop digipeaters.
A simple vertical whip should work very well on HF since you will have a
perfectly conducting infinite groundplane (i.e. salt water) all around
you. I am using a pair of 30M Hamsticks back-to-back as a simple dipole
on 30M APRS, but you could use a single one against ground out there.
The real question is how well will a Hamstick survive salt spray and
ocean humidity. I suppose you could seal it inside a piece of 1/2" PVC
pipe to salf-proof it.
Stephen H. Smith wa8lmf (at) aol.com
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