Operation with an extra GaAs FET preamplifier
A GaAs FET pre-amplifier is easily supported with a coaxial relay and two coaxial cables: the pre-amplifier input socket is connected to the receive [????] output of the coaxial relay via a short piece of coaxial cable. The output cable to the transverter is connected to the output of the preamplifier.
The pre-amplifier shares its power source with the associated coaxial relay solenoid of the coaxial relay. The earth return is via the outer of the coaxial cable.
We recommend the DX1296 as the GaAs FET preamplifier.
Electronic protection circuit
When the LT23S is switched to receive, built-in protective circuitry ensures that up to 10W of 2m RF may be tolerated by the receiver input.
This guards against the possibility that RF is applied to the receive circuitry, perhaps due to a break in the P.T.T. line, or as a result of forgetting to manually switch to transmit mode.
© GJ Coyne & G Mussler Dec-2003