Re: Variable power control

_Dave_ K0MBT
 

I have been powering my bitx40 with a 3s Lipo battery Nominal voltage 12.  last night I thought maybe I could put in a LM317 and set the bias for 12 v and power the radio with a higher voltage lipo. Leaving the power for the power amp at battery voltage. it would be easy enough to change batteries for different power levels.

Things didn't go quite as planned. I think some RF may have gotten into the regulator (a guess) The regulator became quite hot even though i had put on a power transistor to carry most of the load. The sensitivity of the radio was noticeably less. I stopped the experiment for now. The Bitx is my only radio and I didn't want to burn something out. . 

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