Joe Burkleo wrote:
Kevin
Thanks for the information. I figured that if anyone had tried it you
would be aware.
I was just looking for more than 30 Watts out.
Scott and I have been successful in building small IPA's (intermediate
power amplifiers) that take the power from the exciter and make 3/4 to 1
watt with a single transistor. This stage then feeds a Wilkinson power
divider and it feeds two of these brick devices. Another WPD is used to
combine the power. About 75 to 80 watts is possible. We have a
prototype that has one brick module (as the IPA) feeding four more, and
over 150 watts is possible.
We never fully developed the 150 watt high-power version because the
single brick PA we build will easily deliver enough drive for any good
external 220 PA, however we do have several of the 75 watt versions in
service.
Can these modules be considered continuous duty if they are properly
mounted on a Micor station PA chassis.
Absolutely - especially if running one or two modules.
In addition, we actually use the MICOR power set control to retain all
of its features (SWR protection, power leveling, etc.) The AMP BD that
Scott builds has the pass transistor built on it and it is run from the
power set control lead that originally went to the MICOR PA.
Scott also builds a custom heat spreader that is used to mate the module
to the MICOR heatsink. This eliminates the need to machine a flat spot
on the heatsink that big enough for the surface of the module. While
Scott doesn't advertise these, I feel sure he would sell them
individually; they are used in /our/ custom 220 MICOR conversions. The
heat spreader is not necessary in a MASTR II conversion, as there are no
protruding 'bosses' for the original mounting of the RF power output
transistors. The pictures in this document shows the mounting
arrangement he has developed:
http://www.repeater-builder.com/products/ampbddocs.pdf
Good luck and let us know how you make out...
Kevin Custer
Repeater Builder
