Nate and group, Sorry, I know this will get me flamed but I am getting used to it. A isolator does not necessarily make a good installation. A good bandpass High Q cavity/BpBr duplexer in most cases will do everything you need done without the added headaches of a isolator, especially in high power installations.
I learned this from Lloyd Alcorn, one of the owners of Wacom Products and also had a long history with DB Products. Unless you are in a extremely high RF area you are better off not using a isolator. You must use a cavity after the isolator anyway so try it without the isolator and if you still have problems you can install a isolator. Nothing lost. The problems with isolators is they drift with age and heat, especially on high powered installations like the paging systems I used to work on. We never used a isolator unless we were on a Motorola site that required it, which is a bad thing. Isolators are great harmonic generators to boot, hence the requirement of a good cavity. Again, just giving my opinion from my experience and mostly from Lloyd's, he's the smart one! Paul -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] Behalf Of Nate Duehr Sent: Tuesday, January 24, 2006 3:35 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Squeeling Problem Resolved!! (I hope) Bob Dengler wrote: > At 1/19/2006 08:17 AM, you wrote: >> Ok guys I think I resolved the squeeling problem. I Got to the site >> this morning while guys were using the rptr and the problem was >> existing. When tuning the PA awhile back I noticed if you went to far >> one way it would oscillate (feedback, whatever) or go spurrious. Where >> I thought was the proper setting was just on the edge of this. I >> retuned the PA and all cleared up. Even cleaned up Rec'd audio just a >> bit. >> This has been happening more in the early mornings. May be the frost, >> dampness on the antenna created a slight impedence mismatch. Using a > > If slight antenna impedance changes are causing your PA to oscillate, your > PA needs servicing or replacement. At the very least you need an isolator > on the PA output so it "sees" 50 ohms across the band. > > Bob NO6B Correction: All good quality repeater installations should have an isolator on them to keep other RF from entering the PA from external sources and causing various problems. Ham repeaters should not be lower quality than commercial installations. :-) (All of our commercial 2-way and broadcast sites now have isolators listed as required equipment in the contracts these days anyway, so it's not an option for us to leave them off, anyway. Hams in rural areas with no other transmitters on the sites don't know how good they have it...) Nate WY0X 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/
