Mitsubishi RA35H1516M PA          Block Module modification to four metre operation.

This module has been available for some time ex equipment. Its intended frequency of operation is around 157Mc/s but it can be modified to produce about 25 watts output with an input of only 100mW on four metres. (NB, the module performs well on 2 metres without any modification).
The picture below shows its appearance once the black plastic cover is removed.

                Remove all 16 of the surface mounted devices highlighted in purple shown below.......................

Fit the link and replacement capacitors C1 and C2 shown in the picture below. C1 is a 180pF SMD capacitor and C2 is 150pF ceramic type (NOT SMD in this location).

After doing these mods the output was found to be remarkably clean as shown on the spectrum analyser trace below, however a suitable low pass filter should of course still be used after the module.

BEWARE, if you attempt the "Three Capacitor Mod" which came with many of these modules to enable coverage down as far as 1.8Mc/s you will be greeted with more harmonics than you ever believed possible!....Don't do it.

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