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.
p8
© GJ Coyne & G Mussler Dec-2003