I forgot to tell my "parasitic" story..see below...

On Wed, 13 Jul 2005 wrote:

Date: 13 Jul 2005 14:05:17 -0700
From:
Newsgroups: rec.radio.amateur.homebrew
Subject: QUESTION: Fun with Svetlanas or Staying alive with kV power supplies

My knowledge of vacuum tubes and kV power supplies is limited. I have
been reading an article in the ARRL Handbook detailing the construction
of a 1kW HF Linear. I'd like to try my hand at building something like
this. I found the article a little intimidating: Ceramic insulators,
parasitic suppressors, thermal and mechanical engineering etc. Is
there some book that details this type of thing with an explanation of
the whys as well as the whats and hows. My priorities a

1) Safety. I'd like to be alive to make my first 1kW QSO
2) Avoiding equipment destruction, arc overs, black smoke, explosions
etc
3) Safetly troubleshooting this kind of equipment, loading testing
etc.
4) How to deal with tubes: warm up, care, etc...
5) Avoiding TVI (ITV), parasitic oscillations etc.

I built this two 811-a linear amplifier way long ago. Basically ave power
300 watts DC input. So, I made my own parasitic suppressors (turns of wire
over, say, a ten ohm two watt carbon resistor. Or adjust turns). This was
for a 75 meter phone band.

So, on launch day it sits there like a scared bird. Turn on fil power,
plate power (this is grounded-grid for stability and minimal if not zero
need for neutralizations), and tune (no drive) the plate capacitor.
Result: dang, RF output through the power meter AND smoke comes out the
top of the amp and I stand up, look down, and the coils of wire (made of
#22 or 24 gauge wire, can't remember) around the resistors are glowing red
hot! Too many turns of wire, so next time around I cut back to half and
all was OK. Including no self-oscillation in the two 811-As.

That's called trial and error. Or, try, smoke, fix. Like if ready, fire,
aim does not work, change the order to ready, aim, fire.

Art, W4PON


6) Longevity and Duty Cycle issues etc.
7) Costs and sources.

Hope someone can help.

Thanks,

Tim