I'm trying to tune the high side of a TXRX WP-652A duplexer. This is the duplexer where the couplings adjustment is loosening 3 screw on the duplexer connector and turning the assemble to adjust the reject frequency. I'm using this on the 220 ham band, 224.84 TX, 223.24 RX.
My starting point was to adjust the rods and coupling for maximum TX out of the duplexer, then back off on the couplings for maximum reject at my RX frequency. The RX notch is actually below my noise floor on the spectrum analyzer, so I'm adjusting it so the center of where the notch would be is on my RX frequency. In other words it's maximized for my TX frequency and minimized for my RX frequency. When I hook up the transmitter, and put 25 watts into the duplexer, I'm getting 10 watts out (per Bird 43). According to the duplexer spec I should only be losing 1.2dB. Something tells me I have the coupling set too tight, but how far should I widen it? Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
