Robert, I put 50 watts and 0.3 uV at GMRS frequencies into my Comm Shop for Windows program, and it suggests that 73 dB of isolation is needed to avoid desense. This amount of isolation can be achieved with about 39 feet of vertical antenna separation or about 1020 feet of horizontal separation. Since you can use a typical mobile notch duplexer for this application, it hardly makes any sense to erect a tower so that you can run two antennas. Even so, you should elevate your antenna as much as possible if you expect to get any decent range.
73, Eric Lemmon WB6FLY -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Robert Boles Sent: Saturday, May 29, 2010 9:46 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF) it is 50 watts out, its at my home , and no other repeater with miles of this location and i have the ant and hard line --- On Sat, 5/29/10, ZPO <geekdownra...@gmail.com> wrote: From: ZPO <geekdownra...@gmail.com> Subject: Re: [Repeater-Builder] GMRS Repeater ANT (UHF) To: Repeater-Builder@yahoogroups.com Date: Saturday, May 29, 2010, 9:18 PM Depends on the power level. What type of site will the repeater be located at? A duplexer is probably going to be cheaper than a 2nd antenna and 2nd run of superflex. 73-N5VFF/Brian On Sat, May 29, 2010 at 7:21 AM, Robert <bobe...@yahoo.com <http://us.mc802.mail.yahoo.com/mc/compose?to=bobeic2%40yahoo.com> > wrote: > how much space is needed between the TX and RX ant and which type of cable to use ? > > > > ------------------------------------ > > > > Yahoo! Groups Links > > > >
