  Need Schematic or information for a ICOM AG-25 and/or AG-35
The AG25 and AG35 require that the transceivers they are used
with have internal sequencer circuitry. For example, I have an
IC970 quadband radio with the AG25, AG35 and AG1200 preamps
connected. The IC970 puts 13 VDC up the coax to turn on the
relays and to power the preamplifier (ONLY) during receive. Upon
transmitting, the IC970 drops the 13 VDC PRIOR to transmitting
RF up the cable. If this is sequence is not followed, the
preamplifier will be damaged.  I am also using an SSB
Electronics SP13-O. The SSB preamps include additional RF
switching circuitry to protect the preamplifier when used
without a sequencer.  The ARRL handbook has diagrams for
preamplifier sequencers. Be prepared to build one if you are
going to use the AG-XX series ICOM preamplifiers with non-ICOM
radios. You might find the SSB electronics preamps more suitable
for your application. In either event you will need a "bias T"
which is simply a circuit comprised of a DC blockin