[Amps] Two quick loading questions

[Gary Schafer]

Always dip the plate last.

2- Depends on why you are reducing drive. If doing so to operate cw at 
lower power then do a complete retune with that amount of drive. Tune 
for maximum output as usual and dip the plate last again. Then do not 
increase the drive.

Otherwise once the amp is tuned don't touch any tuning on it. It will 
tune different with lower drive and will not handle higher drive power 
if you tune it up at low drive. It will flat top and splatter if you 
increase the drive from where you tuned it at.

If tuned up at full power, then reduce drive the efficiency of the amp 
drops as you reduce drive. This is normal. That's how they work.

In the case of operating cw at lower drive levels by retuning you 
maximize efficiency at the lower power level. You could operate ssb at 
that level too but if the drive inadvertently goes too high then you are 
in trouble.
For ssb operation it is best to keep it tuned with maximum drive. 
Reducing drive level to cut the power a little is ok. It won't be 
running at maximum efficiency but it will not have a chance of 
splattering either.

73
Gary  K4FMX


George KB2Z wrote:
> I'm sure I'm not the first to ask. I have searched in the archives and 
> did not find a solid answer. I apologize up front and am not trying to 
> waste anyones time. The directions from different  manufacturers dont 
> seem to answer one way.
> As I read the loading instructions for gg hf amps, (2x3-500) they should 
> be fully loaded at full power then the loading increased 5 to 10% to 
> lower the Ig and help stabilize the output. This seems to be where it 
> gets confusing for me.
> 
> 1) After increasing the loading 5 to 10%, should the plate be re-dipped?
> 2) If drive is reduced from 100 to 50W, should the plate be re-dipped.
> 
> Thanks in advance,  George KB2Z
> 
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