{Collins} KWM2 on 250 volts



A couple of decades ago (seems like only yesterday), I built a home brew power supply for the KWM2.  As long as I was building it, I decided to make it the "ultimate" KWM2 power supply.  Had a 1 minute delay after filaments were fired up before application of high voltage.  Also had a regulated and variable 270 volts.  After I got the power supply completed, I fooled around with the 270 volts.  Prior to building the supply, I had noted that some of the dual section tubes ran pretty hot, and with the original power supply the recommended voltage was exceeded.

So, my goal was to run the 270 volts as low as possible to reduce heating of the tubes.  Although I do not remember much of the details, I did note that my transceiver did not run well with less than 270 volts.  In particular, at 250 volts, there was some definite deficiencies.  I do not remember what they are, but I did run the voltage back to 270.

It could have been my particular transceiver and I only mention this as a caution that 250 volts may not be a good voltage for the low voltage supply.

I solved the heat problem by keeping the 270 volts at that and using the IERC finned heat conducting shields on the dual section tubes.

73,  Colin  K7FM
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