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Adding
a small MMIC multiplier board into the enclosure of the
VHF OXCO made a great signal marker for the microwave bands.
This one uses a spare crystal I had at 96 MHz, and provides
strong, stable marker signals for the 2304, 3456, 5760 and 10,368 MHz bands.
If one were to use a 144 MHz crystal, markers would also be
available for 144, 432, and 1296 MHz.
Hearing the signal only requires attaching a small "antenna"
to the output (in my case, an inch of bare wire).

I used a small universal MMIC amplifier board to generate the
harmonics. The
actual device used was a MAR-3 equivalent, chosen for it's ability to generate
lots of harmonics (without going bananas) when overdriven with 10 mw from the OCXO.

The multiplier board was spot-soldered to one of the walls of
the OCXO enclosure, and the output coax re-routed to it. Of course, the OCXO
output was routed to the amplifier input, and D.C. power obtained from a spare
8v pad on the other side of the OCXO board.
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