[aprssig] APRS buoy - transmit power and antenna?
Steve Noskowicz
noskosteve at yahoo.com
Tue Sep 11 00:07:11 EDT 2007
Oh, We noticed.
The attached "Line-of-Sight" spreadsheet agrees
pretty close to the URL you posted. It is not clear
if that one has any diffraction correction. I made
this sheet in response to questions about UHF
controlled UAVs my son is designing.
Looks like about 9-10 miles for a bouy to a 30'
station...ignoring any ducting of course. Would make
an interesting experiment, though. You might hit a
satellite at times, but 300mw. sounds pretty thin.
73, Steve, K9DCI--- "Jan T. Pharo" <la2bba at jpharo.net>
wrote:
> "Richard Amirault" <ramirault at verizon.net>, Mon, 10
> Sep 2007 15:23:06
> -0400:
>
> >No one seems to have noticed my comment on limited
> distance of line of sight
> >due to curvature of the earth.[...snip...]
>
> In eyeheight from a small craft (where you stand
> with the feet approximately at sea level) we learnt
in my boating course that I'd have the horizon about 3
nautical miles away (and the web site mentioned above
tell me the same). It might be a good idea to build
the buoy so the antenna is as high above the water
> as possible, in order to increase the distance to
the horizon (and possibly reach a digipeater on a
tower ashore)
>
> --
> 73 de Jan, LA2BBA
> Hvaler, Norway
>
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