The isolator between the PA and the duplexer is fine, but the one between the antenna and the duplexer would only work with a 2 antenna repeater. In a single antenna system most of the received signals would end up in the reject load of the isolator between the antenna and the duplexer. If you want real performance the 2 antenna way works well, assuming reasonable antenna separation on the tower.
Jack K6YC ----- Original Message ----- From: "Kris Kirby" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, February 07, 2006 11:15 PM Subject: Re: [Repeater-Builder] Duplexer questions > On Wed, 8 Feb 2006, N9WYS wrote: >> running about 50W with the old PA. (BTW - There is an isolator between >> the duplexer and the PA.) Will this cause me any grief either now or > > Here's a thought -- if you put a isolator between the PA and the duplexer, > and a isolator between the duplexer and the antenna, wouldn't your > duplexer see a near perfect 50 ohms at all times? > > I've heard one local ham talk about his theories of repeaters, and he > strongly supports making sure the SWR is as low as possible. I used to > think he's nuts, then I realized there is some truth in that -- at a > minimum SWR, the antenna is as close to matched as possible, even if that > is slightly off frequency. It makes sense to me that if the PA is > expecting a 50-ohm load, and the antenna is 50-ohms, then the SWR will be > 1:1. > > Comments? > > -- > Kris Kirby, KE4AHR <[EMAIL PROTECTED]> > "BIG BROTHER IS WATCHING YOU!" > This message brought to you by the US Department of Homeland Security > > > > > > Yahoo! Groups Links > > > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
