Date: Thu, 04 May 2017 23:29:59 +0000
From: Manfred Mornhinweg <manfred@ludens.cl>
To: amps@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
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