[Johnson] Why amplifiers v. plate mod?

[Roy Morgan]

At 04:02 PM 5/28/02 -0700, Cal Eustaquio wrote:
>All:
>I think I already know this but I wanted your opinion. I keep hearing
>about hams juicing up their normally SSB linears to amplify AM. Is
>this supposed to be better than running a plate modulated rig of the
>same power class?


Depends on what you mean by "juicing up" and also on what you or they mean 
by "better"

The "juicing up" normally needed to be done in the  power supply.
The "better" may be from the idea that running a linear amplifier you 
HAVE  on AM is cheaper than buying or building a new transmitter or final 
stage.

Facts about this:
  1)  Most/many linear amplifier power supplies meant for SSB service would 
not support steady state use in AM serivice.
  2)  Many hams did/do not understand the use of Linears in am service.
  3)  The linear has a maximum carrier power it can deliver (still being 
linear).
  4)  The principles and engineering factors involved have been clearly and 
repeatedly explained.
  5) Measuring "efficiency" of a linear amplifier used in AM service 
normally leads to unimpressive numbers.
  6) Running a linear amplifier properly with a clean AM input signal 
produces a stronger AM signal that sounds just fine.
  7) The TMC company built transmitters operating on with these conditions 
for years. You can hear some today by tuning to 5.0, 10.0, 15.0 or 20.0 mc. 
(WWV)

Roy



>  For some reason, I think AM done in this manner
>wastes more power than a similarly plate modulated rig. What gives?
>Thanks.
>
>Cal, N6KYR.
>
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- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
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