One might consider terminating the unused pole of a converted duplexed commercial radio tr relay... say into a 50 ohm resistor.
Relative to the grand scheme of things maybe even remove the relay. A reed relay is probably fast enough but many/most mechanical relays might be suspect for "hot switching" the output with rf present, which is not good news for the equipment and the distorted signal that might be placed on the air... maybe at every relay cycle. The final section of most good pa sections should be followed by some type of filter. At least we would hope so... It would be hard to make a global rule about looking back at the transmitter/pa output impedance in standby/off mode. The use of a circulator/isolator would be the best fit. cheers, skipp > > Bypassing the relay shouldn't have an effect on the TX output > > Z when not > > TXing, as the final RF output transistor is going to look > > like an open too. > > Bob NO6B > > But the "open" transistors would be at a different electrical distance away > from the duplexer than the open T/R relay was. >
