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P-Comm Transceiver: In 2000 and 2001 I picked up two surplus microwave convertors made by P-Comm consisting of two harmonic mixers, IF, LO, and diplexer. They were set up for 23 GHz so only the harmonic mixers are of use for a 24 GHz tansverter. Al Ward, W5LUA, tested the mixers with several combinations of LO and IF frequencies and they performed best as using 2X 10.368 GHz mixed with an IF of 3456 MHz. Here is Al Ward's paper (pdf). Looking at the block diagram (below) the transverter consists of a 10.368 GHz LO which I will construct using a DEMI WSS (MicroLO) frequency controlled by a Refloc circuit (GPS Ref.) to a surplus 8X multplier chain that I purchased from e-bay (Pyrojoe) followed by a multi-stage buffer amplifier to boost power to 30 mw. That will be spilt between the two harmonic mixers. The transmit side has approx. 20mw of 3456 MHz IF drive being mixed with 20.736 GHz to produce about 10 mw output on 24.192 GHz. The receive side works in reverse to feed a DEMI 144/3456 xvtr. The harmonic mixers output is WR-42 which is routed thru a 4-port waveguide switch for T/R switching. This goes to W1GHZ dual-band feedhorn illuminating an 18-inch offset feed dish. The two 24 GHz tranverters are designed for portable use. Here is a block diagram: Photos will follow as work is done on the units.
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