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[aprssig] APRS for a "ocean buoy"

Stephen H. Smith wa8lmf2 at aol.com
Tue Jan 9 04:59:35 UTC 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
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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
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