My 6 meter and 2 meter antennas on my rover are a foot apart. I use a TE
systems 0552G on 6 and newer Mirage B "30"16 on 2 meters, and full output
on both setups. BUT also a HF/6 duplexer on the output of the 6 meter rig
to split off the 100W of HF to its tuner/antenna ahead of the amp. Also a
serious TVI filter which rolls off everything above 55 Mhz to 60dB or
better, after the amp. I don't think 144 Mhz gets thru it at all... The
144 Mhz station runs thru a single Sinclair bandpass cavity.
Both stations can run with the preamps on with full output and NOT
INTERFERE WITH EACH OTHER AT ALL! This has been verified numerous times.
I had a much bigger problem with an Icom 706 MkIIG on 432 tearing
everything else up, filters and all! So got that pulled out of my rover
setup...
The 222 setup runs thru a DCI filter, and 432 thru a harmonic linefilter
removed from a Motorola paging transmitter. Still get 3rd harmonic on
1296,
but around 40dB lower than without. Not enough to desense on 1296.1 with
the 432 station running 100W.
Thing is, that sinclair cavity is 10 inches in diameter and 2-1/2 feet
tall, not including the tuning rod. It does fit nicely on the station
bench next to the radio and brick, but the "average" rover just does not
have a whole lot of room for stuff like that. Probably the neatest thing
about those DCI helical filters besides more "in-band" bandwidth...
Eric
KB7DQH
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