[Amps] Fwd: Linear Amplifier Tuning---PROPERLY!

[Eddy Swynar]

On 2011-12-21, at 7:55 AM, donroden at hiwaay.net wrote:

> Isn't it true that if you re-peak the tuning control, then the loading  
> is no longer "over-coupled" ?
> 

Hi Don,

I think you've hit the proverbial nail right on the head with that observation---which, BTW, was pretty much the very same opinion that the majority of originators of the last batch of e-mails that I received here on the subject had, as well...

Probably the best easy-to-grasp response (for me, anyway!) that I read here as to why it is NOT desirable to re-tweak the plate TUNING capacitor as a final step in the tuning process of a linear amplifier, came from Steve (KK7UV), who was told---when asking a similar such question himself some time ago---that "...the answer was something like 'if you do that, you change the load line and you play cat and mouse between the tuning and loading caps'". 

Makes sense to me, I s'pose...

Too bad the movers & shakers in the Amateur radio world of literature---from Bill Orr back in the day, to the present crop of technical gurus on-line---couldn't be as descriptive! Hams, by their very nature, are inveterate knob-twiddlers & adjusters----so why WOULDN'T we re-adjust things "...one final time" during a tuning-up process...?! A simple & final "HANDS OFF!" warning after the over-coupling procedure in the descriptive literature would suffice! Hi Hi.

~73~ de Eddy VE3CUI - VE3XZ