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[AMPS] L-Net calculations: Am I doing something wrong?

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Subject: [AMPS] L-Net calculations: Am I doing something wrong?
From: (Rich Measures)
Date: Thu, 18 Feb 1999 01:38:09 -0800

>>>Why does my power output top out at 800 Watts?  Once I get over 60 watts of 
>>>drive, I get no more power out no matter what I do.  
>>?  Sounds like a tuned input problem.  What is C1?
?  The input C on the Pi.  

>Interesting.  I forget what C1 is.  I would have to check.  I have thought 
>it might be a problem given the fact I am using slug tuned coils.  Perhaps 
>the slugs start to saturate.  The 10m input SWR isn't perfect right now, 
>but is under 2:1.  I need to adjust the slug a bit.  But what does flat 
>topping have to do with the value of C1.
Flattopping has to do with not enough peak cathode emission to go with 
load presented to the tube by the tank.  
>>>The current will 
>>>change depending on what amount of drive you have applied to the amp.  So 
>>>I what I think you are saying is that you would need to drive the amp so 
>>>that the plate current is at 0.8 A.  But then if you decrease the drive, 
>>>you would change the impedance and hence the match.  Correct?
>>?  yes x 3.  The guy who wants to take it easy on his linear amp. and 
>>tunes up with reduced drive, gets a mistune every time.  .  . 
>Well, correct.  However, I was taught to tune it up initially with low 
>power and then gradually crank up the power, tune it, crank the power 
>more, tune it, etc. until you get to full desired output power and then do 
>a final tune job on it.

Tuning-up one time at full-throttle saves time.  Tuning up at low power 
wastes time.  Amplifiers are designed to work at full-throttle.  
-  later, Jon


R. L. Measures, 805-386-3734, AG6K,  

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