[Amps] High voltage MOSFETs

[Jim Thomson]

Date: Thu, 04 May 2017 23:29:59 +0000
From: Manfred Mornhinweg <manfred at ludens.cl>
To: amps at contesting.com
Subject: Re: [Amps] High voltage MOSFETs

###  has anybody actually used a tuned circuit in any 
of these proposed configurations ??   I just cant fathom
manually tuning up a SS amp..... unless  you were 
really careful, and pulse tuned it with a low 3-10 % duty 
cycle, and also starting with low drive power.  This
would be one application, for a  6:1   or  10: 1
vernier drive, with well calibrated  large diameter  skirts.
So once you have tuned it on all bands, then log the numbers.
Or use a groth type counter, to drive the vernier.  At least
then the skirt circumference is  calibrated from 0-100.
Then each revolution is broken into 100 increments. 

That or some form of high tech auto tune, alpha style 
config..with loads of pre-sets and memories.   And will
it handle higher swrs ?   Or do we have to go through the
rigmarole of a manual or auto tuner ?  

Jim   VE7RF 






< And the "conventional" layout of a single-ended stage with a TUNED 
OUTPUT NETWORK might even appeal to people used to tubes!

<Yes. Either using fixed-tuned networks per band, switched by relays just 
as if they were lowpass filters; Or using a single, TUNABLE NETWORK, 
which could be MANUALLY or automatically TUNED.

The switched network approach is no-tune, but requires lots of high 
current, high voltage capacitors and coils - much more so than lowpass 
filters, due to the higher Q. It would probably prove too expensive and 
bulky. Which leaves us with a single, TUNABLE NETWORK, very much as in a 
tube amp. Using VARIABLE CAPS, tapped/switched inductors, etc.


In other words, I'm proposing to use devices like this in a TUNED 
AMPLIFIER, running class C, E or perhaps F or inverse F, in an EER 
amplifier driven by an SDR.

Manfred