[CQ-Contest] Output pad for running QRP?

Tom Rauch W8JI at contesting.com
Sat Sep 29 20:18:22 EDT 2001

> What about adding a loop thru at the output of a low-level stage and
> adding a pad at that point? This would limit power without introducing
> bias changes and while avoiding the need for 50 to 100 watt rated
> pads.

The problem is the output and driver stages are often not biased 
high enough to be exceptionally linear at low power levels.

Keep in mind cross-over (or bias threshold) distortion is a problem 
in some bipolar transistors.

You would also not have ALC if you padded an early stage.

Running QRP isn't near as much of a problem as reducing power to 
drive a PA. Reducing exciter power is messy. I remember all the 
160-meter transverters and how many bad signals there were, 
because the transverters drove with two or three watts.

73, Tom W8JI
W8JI at contesting.com 

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