[aprssig] APRS buoy - transmit power and antenna?
Scott Miller scott at opentrac.orgTue Sep 11 05:19:19 UTC 2007
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Assuming you're in the open ocean and only care about hitting a satellite, is the J-pole going to give you a suitable radiation pattern? Or would a 1/4 wave be better? Scott N1VG R. Simmons wrote: > 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 >> >> > ____________________________________________________________________________ > ________ >> Shape Yahoo! in your own image. Join our Network Research Panel today! > http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7 >> > > > ---------------------------------------------------------------------------- > ---- > > >> _______________________________________________ >> aprssig mailing list >> aprssig at lists.tapr.org >> https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig >> > > > _______________________________________________ > aprssig mailing list > aprssig at lists.tapr.org > https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig > >
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