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Re: Meissner oscillator

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> In a message dated 2/9/01 1:51:30 PM Eastern Standard Time, tesla-at-pupman-dot-com
> writes:
> >
> >  3. Of course it is possible as well to wire the frequency determining
> >  components into the control grid circuit e.g. by paralelling the grid
> >  coil by a capacitor. In this case no tank capacitor is used. This
> >  circuit is a modification of the standard Meissner oscillator circuit.
> >  The drawback here is that the output power is smaller, because
> >  there is no resonant rise in the plate coil. Therefore this
> >  modification is used as local oscillator in receivers mostly.
> >
> >  Mark Rzeszotarski has built such a small VTTC which produced a
> >  1" brush.
> Herwig, all,
> I built this type of coil also,  and it gave only a 5" spark, even
> when rather tightly coupled.  When running in the normal tuned
> plate mode, it gave a 7" spark.
> John Freau

	An oscillator is an oscillator.  If there are no excess losses any
oscillator with the same grid drive power should produce the same power
output, provided the plate circuit presents the same resistive load to
the tube.  Differences may be in impedance presented to the tube,
ability to couple that power to the load (coil in this case), etc. 
Bottom line is that, if the circuit is designed right, there should be
no significant differences.  Not suggesting the design techniques, of
course.  By the way, the Meissner circuit has always seemed awkward to
me; I prefer simple Colpits or Hartley oscillators.  A lot of these
circuits are basically the same, just depending on what node is
grounded, but were used to get around patents.  In this regard, the
Meissner is different.

	Should mention that when an oscillator drives a relatively high-Q
resonant load such as a TC, circuit adjustment can be much harder than
when matching into an antenna or other low-Q load.