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[aprssig] APRS buoy - transmit power and antenna?

R. Simmons pelican2 at silcom.com
Tue Sep 11 05:09:17 UTC 2007


You folks should consider wave height also... in calm seas, not a problem,
but heavy swells in a storm can easily render a buoy obscure ( in a trough )
and therefore "intermittant".

----- Original Message -----
From: "Steve Noskowicz" <noskosteve at yahoo.com>
To: "TAPR APRS Mailing List" <aprssig at lists.tapr.org>
Sent: Monday, September 10, 2007 9:07 PM
Subject: Re: [aprssig] APRS buoy - transmit power and antenna?


>
>  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
> >
> > _______________________________________________
> > aprssig mailing list
> > aprssig at lists.tapr.org
> >
> https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
> >
>
>
>
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