1. BITX20@groups.io

Re: Variable power control

Arv Evans
 

John  G0UCP

Agreed.  Some just can't have enough knobs and some percentage of those "must have
them turned to the right-most position". 

There is also the problem of change in operating parameters when power levels are changed
without a good idea of what the effect might be. 

Attenuators for QRP power levels are inexpensive and easy to build.  Add a switch or relay
and they allow the exciter to run at design specifications and still have controllable output. 

Using an attenuator on the input of a power booster helps insure that the impedances are
matched (maybe!) between exciter and linear amp.

HAPPY NEW YEAR! 

Arv  K7HKL
_._


On Mon, Jan 1, 2018 at 12:54 PM, John Seager <jseager2009@...> wrote:
Arv, a) Happy New Year. b) Aside from using an attenuator, drive is controlled by
the preset RV1. This could be replaced by a variable pot., perhaps on the back panel. 
However I think it was Farhan who pointed out a long time ago that the only problem
with this is the temptation to keep turning it up!  73,  John  G0UCP



On Monday, 1 January 2018, 17:05, Arv Evans <arvid.evans@...> wrote:



On Mon, Jan 1, 2018 at 9:19 AM, <ad4xx@...> wrote:
I'd love it if I could add a variable control to adjust output power on the uBitx.  After looking for solutions, I understand now that it's not a simple add of a potentiometer.  Anyone done this yet?




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