[Prev][Next][Index][Thread]

Re: tubes??? 4CX250F



Subject:      Re: tubes??? 4CX250F
       Date:  Fri, 23 May 1997 21:00:17 +1000
       From:  Phil Chalk <philoc-at-ozemail-dot-com.au>
Organization: Secure_Logic
         To:  Tesla List <tesla-at-pupman-dot-com>
 References:  1


Tesla List wrote:
> 
> Subject:  tubes??? 4CX250F
>   Date:   Thu, 22 May 97 05:54:18 UT
>   From:   "William Noble" <William_B_Noble-at-msn-dot-com>
>     To:   "Tesla List" <tesla-at-poodle.pupman-dot-com>
> 
> a long time ago I used to work for Collins radio  - 

Lucky boy !

4CX250F.  If I remember right, these came out of kilowatt HF airborne
> commercial radios. 

I was once the proud owner of a KWM-1  (I hope to get it back again some
day)

The KWM-1 (ex Mawson Base, Antarctica) was originally fitted, I believe,
with a pair of 4X150A's (glass base), but when I got it it had a pair of
4CX250B's in it (I still have a brand new pair, by Eimac) These are a
ceramic (Berillium Oxide !) based, higher power version. The 'C' in 4CX
says 'Ceramic'.  They are a beam power tetrode, from memory.

I don't recall the specs, but in the KWM-1 they ran with 2kV dc on the
plates, and were good for about 1500-2000W PEP, I think.

I think I have some data on them, somewhere - at least an Eimac
spec-sheet.  If I can find any I'll mail to you.  The 4CX250B data
should be very close in most respects - I do not know the significance
of the 'F' suffix.

I also have no experience (yet, unfortunately) of tube Tesla coils, but
I think they could be of some use.  Certainly that thought crossed my
mind, for my pair.  However they do need a LOT of forced-air cooling
(with special sockets, chimneys, etc) for full-rating operation, and
Plate dissipation is very much reduced without it.  Others here will
have a better idea of their suitability.

Cheers,

Phil Chalk.