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Re: [Amps] Two quick loading questions

To: George KB2Z <Thermionic_Emission@earthlink.net>
Subject: Re: [Amps] Two quick loading questions
From: Gary Schafer <garyschafer@comcast.net>
Reply-to: garyschafer@comcast.net
Date: Wed, 09 Feb 2005 17:14:40 -0500
List-post: <mailto:amps@contesting.com>
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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