Re: VTTC - audio modulation

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Herwig Roscher by way of Terry Fritz <twftesla-at-qwest-dot-net>" <herwig.roscher-at-gmx.de>


Dr. Duncan Cadd wrote:

> The fact that the quiescent operating point is at the foot of the 
plate current characteristic simply means that the circuit will 
respond to low level grid input signals, which of course a class C 
amp won't.

Duncan, All!

Therefore I've reduced the number of grid coil turns when converting 
the class C oscillator to class A.  As it is not very comfortable to 
remove a turn, test the oscillator, remove another turn..., I'll 
connect a variometer (salvaged from a diathermy machine) off axis 
to the primary coil. Hopefully it will be possible to vary the feedback 
voltage to the control grid easily.

> using a roller-coaster inductor and it worked fine.
-             ~~~~~~~~~~~~~~~~  This was the expression I was 
looking for!  ;-)

> But it seemed somehow appropriate given the context . . .
- It hits the point! 

> making noises about a German Teslathon
- The only coil I've seen running so far was at the University of 
Hannover. No other coilers within some 100 km. One of the 
reasons may be, that the EMV (electro magnetic pollution) rules 
are very strict in this country. Another, that it is very difficult to spot 
NSTs.

Regards,

Herwig