Ian, Of the two methods you propose, the first is better by a long shot. It is never a good idea to transmit into an untuned duplexer, for any purpose.
If you don't have access to proper duplexer tuning equipment, such as a network analyzer or a spectrum analyzer with tracking generator, the "receiver s-meter" method is crude but will get you close. The down side is that this method lacks the great sensitivity and precision attainable with a network analyzer- the instrument of choice with duplexer manufacturers. Perhaps the best advice I can offer is to contact the manufacturer of your duplexer, and ask for a copy of the field tuning instructions. There is no "single standard procedure" for tuning duplexers, so it helps to know what method is recommended by the firm that built it. 73, Eric Lemmon WB6FLY Ian Wells wrote: ...When tuning cavity filters, which is the best way of alignment- having a signal generator hooked up to the tin with a radio with signal strength meter on the other side, or transmitting on the radio with an swr meter in line with tin into a dummy load?... Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/