--- In Repeater-Builder@yahoogroups.com, Paul Kelley N1BUG <paul.kelley.n1...@...> wrote: > > I guess I was lucky in my first few years as a repeater owner. > Lately I have nothing but grief in many forms. (Yeah I know, welcome > to the real world!) > > Can someone tell me in basic terms what is the difference between an > isolator and an intermod suppression panel which contains an isolator? > > If one has a high power tube PA on a repeater, I assume he would > need to use a high power isolator or intermod panel after the PA? Or > would it be sufficient to use a lower power one between the solid > state exciter and tube PA? > > Thanks... > > Paul N1BUG
The isolator prevents power from the antenna from entering your transmitter where it can mix with your output and cause intermod products. In the process of doing this the isolator also generates harmonics of your transmitter output so you *MUST* also use a cavity between the isolator and the antenna to suppress the harmonics. An additional benefit of an isolator is that it protects your transmitter from a damaged antenna system. If the antenna has 100% reflected power all of that power will end up in the isolators load so plan accordingly. So no isolator between the exciter and the PA does no good at all in preventing intermod. 73's Skip WB6YMH
