[CQ-Contest] Cheating - Big Amps

[e73m at e73m.com]

Thanks for advice,

  I guess driving 3cx3000 with 100W is not feasible but is it clean 
enough?


73 Danny, 4O/E73M

On Wed, 7 Sep 2011 10:12:52 +0200, Marijan Miletic, S56A wrote:
> Once upon a time Alpha made a good tube linear amplifiers but than
> came Acom :-)  E73M quote of 3 sentences from 8100 manual carries 
> some
> hype.
>
> If 50 W of drive is required for legal output of 1500 W, further
> reduced drive of 33 W (for 1.000 W output) would be even less
> RF-clean.
> If manufacturer is so concerned about that, 3 dB input attenuator
> would be appropriate for standard 100 W drive.  That is included in
> most solid state amps.
>
> Ohms law defines load as ratio of voltage and current while power is
> the product.  Therefore power is voltage squared divided by load.
> There is CW/SSB switch on some lighter tube amps which just increases
> plate high voltage enabling less load retuning on lower CW/RTTY power
> level.
> Fixed HV PSU just requires higher load for reduced power.  One should
> always tune amplifier on maximal power intended for use in order to
> achieve optimal efficiency.  Retuning might be required if antenna 
> SWR
> changes a lot with the frequency.  Your amplifier is just an active
> antenna tuner providing some gain.  This bragging is dedicated to YU7
> friend who managed to cook tubes by tuning amplifier to the highest
> number of red plate LEDs :-(
>
> 73 de Mario, S56A
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