Anyone that followed my 440 Mhz D-Star repeater build saw that I purchased an inexpensive 50 watt duplexer from a Hong Kong retailer, similar to the one listed here on ebay: 50W UHF 6 Cavity Duplexer SGQ450 N for GM 300 GM 950 | eBay
All of these units are advertised as having isolation of better than -75db, which isn't too bad for a unit in the $100 price range. Well, I had a reason to change the frequency range mine is tuned for and thanks to Daryl, N6DTO I can honestly say that the numbers are a lot better than advertised. Check out this analyzer plot showing the unit tuned for -96db isolation on the upper frequency! That's pretty impressive!
All of these units are advertised as having isolation of better than -75db, which isn't too bad for a unit in the $100 price range. Well, I had a reason to change the frequency range mine is tuned for and thanks to Daryl, N6DTO I can honestly say that the numbers are a lot better than advertised. Check out this analyzer plot showing the unit tuned for -96db isolation on the upper frequency! That's pretty impressive!
