[aprssig] APRS for a "ocean buoy"
cap at cruzio.com
Tue Jan 9 00:14:35 CST 2007
Most parts of coastal California are populated with nearby mountaintop
digipeaters. VHF could work fine much of the time (because of the digis
atop those mountains). But if "conventional satellite tracking (Argos,
Orbcomm, Inmarsat D+)" alternatives are available, then APRS (VHF or HF) may
not be the most appropriate mode.
73, Cap KE6AFE
Perhaps the California APRS Users group could provide more local info.
News, discussion, and questions about APRS in California (and nearby
portions of adjacent states) will continue there.
> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org
> [mailto:aprssig-bounces at lists.tapr.org]On Behalf Of Stephen H. Smith
> Sent: Monday, January 08, 2007 21:00 PM
> To: TAPR APRS Mailing List
> Subject: Re: [aprssig] APRS for a "ocean buoy"
> 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
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> > aprssig at lists.tapr.org
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> 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
> EchoLink Node: 14400 [Think bottom of the 2M band]
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