[Milsurplus] FW: [regenrx] Submini tubes

[Hubert Miller]

I thought this was of possible wider interest so i'm forwarding it. 
-Hue 

-----Original Message-----
From: Hubert Miller [mailto:kargo_cult at msn.com] 
Sent: Wednesday, June 22, 2016 5:05 PM
To: regenrx at yahoogroups.com
Subject: RE: [regenrx] Submini tubes

Leonard - your observations are very interesting. I thought the minimum
non-gas tubes were rated at was 100 hours, such as the 5676 tube. I first
learned about the limited life hours rating recently in a military manual
that described the tube purpose rather than detailed specs. I had known for
some time that some gas tubes, and i'm thinking of the RK-61 submini, had
lifespan rated in hours. ( This was a gas tube used in radio control ship
and plane models of the 1950s, used in a superregen circuit, usually on 27
MHz CB. )  The texts on that tube say the larger the plate current, the
shorter the life of the tube.
I wonder what exactly is going on with your V.T. fuze tubes. 
I think they operated on around 300 MHz in the V.T. fuze weapon. I have a
book on the V.T. fuze  "The Deadly Magic", but it's packed away now. 
-Hue Miller

-----Original Message-----
From: regenrx at yahoogroups.com [mailto:regenrx at yahoogroups.com]
Sent: Wednesday, June 22, 2016 11:48 AM
Has anyone experimented with proximity fuze tubes? I used a couple in my
Mk.19. They worked very well at first, but now aren't doing so well. The
tubes were not designed to last very long, maybe 10 seconds or so. I
breadboarded a few to see if I could develop some characteristic curves, and
noticed that they degraded the longer I kept them on. Therefore, I don't
think it's worth persuing the project any further. Now I'm working on some
submini tubes that seem to be hearing aid tubes. They're triodes and the
only markings on them are 433 and 447. They seem to have a greater mu than
the proximity pentodes and have a higher frequency response, up to 10MHz or
better. The proximity pentodes seemed to peak around 600KHz, maybe because
of the breadboard setup. With a crystal the 433 and 447 readily go into
oscillation, so I'm sure they'll work as regen detectors. The next step is
to see if I can measure the mu and gm.

Leonard




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