Re: 811A any good?

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

Original poster: "David Trimmell by way of Terry Fritz <twftesla-at-uswest-dot-net>" <davidt-at-pond-dot-net>

Hi, AKA "sputter mode". I have tried this, and found it to be very hard on 
all components, especially tubes (only time I had a 833 arc internally). 
Ed, I would be very curios as to the circuit details of such a self pulsed 
design. I have used 304's and was able to get 16" spark from a classic VTTC 
Staccato circuit. I find that there plates run almost incandescent at rated 
Voltage (class C) of 3000V, not really tempting me to push the voltage. The 
833C, with graphite plates can really be pushed, I've run them up to 5500V 
in Staccato mode (~2 to 30 PPS) with stone cold plates.

Regards,

David Trimmell
www.ChaoticUniverse-dot-com

At 09:07 AM 1/27/01, you wrote:
>Original poster: "Dr. Duncan Cadd by way of Terry Fritz 
><twftesla-at-uswest-dot-net>" <dunckx-at-freeuk-dot-com>
>
>Hi Ed, All!
>
>Date: 26 January 2001 00:09
>Subject: Re: 811A any good?
>
>
> >Original poster: "Ed Phillips by way of Terry Fritz
><twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>
> >
>
>
><snip>
>
> >As a further
> >note, most of these transmitters were self-pulsed.  At the
>right
> >combination of grid bypass/coupling capacitor and "grid
>leak" the tube
> >will go into conduction, oscillate, and pulse itself off.
>
>Aharrrrr!  The "Squegger" !!!
>
>Great name for a VTTC project :-)  Just what I was intending
>to do with those 813s!
>
>If I recall correctly, around 150-200k for the grid leak and
>150-200pF for the grid cap.  Need a high time constant so
>that the charge on the cap builds up and biases the tube
>(hey, I'm learning the language ;-) to cutoff.  What say
>you, Ed?
>
>Dunckx