[AMPS] 7289's and other uWave tubes

[Carsten Groen]

Hi John,
I used to be on 23 CM EME with a 5M (15 feet) homemade
dish. I used 4 of the N6CA amps in parallel, using 3 hybrids.
The watercooling jackets I used, was made of a piece of copper
tube that fit "almost" inside the tube. On the top of the copper
tube, I place a round piece of coppersheet. The coppersheet was
soldered to the top of the tube. In the copper sheet, I drilled 
two holes, and soldered 2 small pieces of coppertube in these holes.
The hole thing was then put "into" the 7289's and glued with some
two component epoxy. I never had any failures with this approch,
ie no water leakage etc ! I have also used the "screw on" type of 
jackets, but found that this approch was much easier to fabricate.

Carsten Groen, OZ9AAR
http://www.magicio.com/cgroen




> -----Original Message-----
> From: owner-amps@contesting.com [mailto:owner-amps@contesting.com]On
> Behalf Of John Fielding
> Sent: 12. maj 1999 18:36
> To: amps@contesting.com
> Subject: [AMPS] 7289's and other uWave tubes
> 
> 
> 
> Hi all - a slightly off-topic question.
> 
> I am updating my 23cm station for eme and converting the various 
> tubes to water cooling. 
> A question regarding the thread which is used to attach the 
> air-finned cooler to the
> tube anode.  
> 
> In Chip Angle's N6CA article for a water cooled 7289 amplifier he 
> states that the
> thread is 3/8"x16 which I assumed (incorrectly) was UNC.  However 
> when I measured the
> several tubes I had stripped the thread appears to be BSW 
> (Whitworth).  Can someone
> confirm this before I spend my hard earned cash on an expensive 
> tap and die?
> 
> BTW Several of the tubes I have are made by Siemens which use 2 
> different thread forms,
> one is similar to the USA style but appears to be 12mm but a 
> finer pitch than standard. 
> The other type uses an inverse thread, the cooler is threaded on 
> the outer part unlike
> the normal types which are threaded internally.  Anyone care to 
> comment what these
> threads might be?
> 
> I have also designed a water cooling jacket for the Russian GI7bt 
> triode which bolts on
> in place of the air-finned cooler.  If anyone is interested I 
> will send details on
> request.
> 
> Thanks in anticipation.
> 
> John	ZS5JF
> 
> --
> FAQ on WWW:               http://www.contesting.com/ampfaq.html
> Submissions:              amps@contesting.com
> Administrative requests:  amps-REQUEST@contesting.com
> Problems:                 owner-amps@contesting.com
> Search:                   http://www.contesting.com/km9p/search.htm
> 
> 

--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm