On Jul 30, 2006, at 2:26 AM, Peter Chadwick wrote:
> Rich commented:
>
> >>Over the last 60 years or so,
> >> there have been a number of articles on recovering thoriated
> >> tungsten filament tubes. No guarantees are offered, but the process
> >> (which varies somewhat from author to author) are to run the tube
> >> (with no other supplies connected) with twice filament voltage for
> >> 5 minutes,<<
>
> >bonkers<
>
> Well Rich, that may well be your opinion.
Background. When the Plywood Box project was fired up, I discovered
that the donated 8170 pull had little emission. Several 40m friends
told me that I could increase emission by raising filament potential
for a prescribed time. I followed the procedure but emission did not
increase. In the end, I sent the pull to Econco Broadcast Services
with a cheque for $400, had the filament recarburized, and emission
was restored. I later discovered that the aforementioned procedure
only restores emission with thoriated tungsten filaments that have
been operated for a long time below the mfg's minimum recommended
filament V.
> But the articles in the T &R (later RSGB) bulletin on this would
> have been reviewed by either Jessop, G6JP, or Corfield, G5CD - or
> both. Both of these guys spent their working lives in the design
> and manufacture of valves - all the way from receiving to 100kW
> output demountable ones.
The design of the Ford Pinto was peer-reviewed by other Ford
engineers and approved.
> So I know whose opinion I would take notice of, and this time, no
> way can it be yours.
But of course, Peter.
cheers
> As I'm afraid to say, that I do on the subject of parasitics.
>
> 73
>
> Peter G3RZP
>
>
R L MEASURES, AG6K. 805-386-3734
r@somis.org
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