A circulator (isolator) is always a good idea, but it really won't do much to match a poorly-designed power amplifier. When I started this thread, the issue centered on the fact that many solid-state PAs do not present a true 50 ohm source impedance. The isolator stabilizes the load placed on the PA, but it won't change the source impedance of the PA.
James has provided an excellent example of how an unstable PA design reacts to a "perfect" load: Not too well! While it is possible to experiment with various lengths of cable to achieve an "impedance transformer" to match the PA to the duplexer, it is almost always easier and quicker to install an impedance matcher right at the output port of the PA. When this is done, the cable length becomes irrelevant. 73, Eric Lemmon WB6FLY 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/
