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Re: [Amps] LDMOS availability

To: Amps group <>
Subject: Re: [Amps] LDMOS availability
From: Bill Turner <>
Date: Sat, 10 Jun 2017 18:03:56 +0000
List-post: <>
------------ ORIGINAL MESSAGE ------------(may be snipped)

On Sat, 10 Jun 2017 11:57:18 -0400, Mark wrote:

>is nothing cast in stone that requires the output in class C to be 
>non-linear, the text simply says it typically is not.  That leaves a lot of 
>room for how to view new ideas and techniques.


Incorrect.  Because it is biased beyond cutoff, a Class C amp does not
amplify the entire drive signal and therefore can not be considered
"linear".  For example, if it is biased so that it conducts during
only 170 degrees, there is 10 degrees of the drive signal missing. 

For simple carrier modes like CW, RTTY or FM that doesn't matter, but
for voice, either SSB or AM, it does and distortion will occur. 

As I said before, "modulating" the bias to make the amp linear, also
makes it NOT Class C while the "modulation" is taking place. When the
"modulation" stops it reverts back to Class C. 

73, Bill W6WRT
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