50MHz "Harris" SSPA Modifications
My amp was actually made by Microwave Modules & Devices Inc. but is
essentially the same as the Harris SSPAs. These SSPAs were widely
available in the USA as a result of the move to digital TV and away from
low-band. The unit does not require any RF train modifications to
produce an easy 1kW output on 50MHz and/or 70MHz.
The images below show my physical modifications, the cooling system and
the construction and testing of a 1kW 50MHz LPF for the Harris SSPA. A
low pass filter is ESSENTIAL as without it the 2nd harmonic is only
20dBc.
The cooling shown, 3 x 7 inch 50v rack fans, is way too much - but I
wanted to be sure that the Harris SSPA would be good for a CCS 1kW in a
tropical environment - it is - with the fans running at about 20% :-)
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