[Amps] SB-220 bias question

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Sun, 30 Aug 2009 21:22:26 +0200, "DF3KV" <df3kv at t-online.de> wrote:

>Circulating current is not increasing because drive is reduced, but because
>Q is increased (L remains the same) by tuning for lower output at higher
>voltage.

REPLY:

That was not the original question. You are talking about RETUNING after
lowering power, and if you do that then I agree - Q will be increased.

The original question asked if anything would be harmed if he tuned up at 1500
watts then reduced the drive to 800 watts. NO MENTION OF RETUNING. ONLY LOWERING
THE DRIVE.

The answer is nothing will be harmed, except that efficiency will be reduced by
a few percent. AS LONG AS YOU DO NOT TOUCH THE TUNE AND LOAD CONTROLS,
CIRCULATING CURRENT WILL ONLY DECREASE WITH REDUCED DRIVE.

Sorry for the shouting, but that is the crucial point that people seem to be
missing in this discussion.

Nobody is denying that if you reduce the drive AND RETUNE, circulating current
will increase. NO ARGUMENT THERE. But  - one last time - THAT WAS NOT THE
QUESTION.

Whew!

73, Bill W6WRT