Re: Some interesting Nuvistor information

Eric Schumacher

When I read CEI my interest perked up. Do you have any documentation that you would share on either the CEI ST2045-2 or the Aydin Vector RLS-2000A receivers, particularly the AV since mine doesn't work and the construction is formidable for a hobbyist to work on.

To continue the thread: The 1968 Heathkit HW-17 2meter transceiver used Compactrons in the transmitter section and FETs in the front end.
73 Eric

-----Original Message-----
From: [] On Behalf Of stevenhorii
Sent: Thursday, June 18, 2020 8:52 AM
Subject: Re: [TekScopes] Some interesting Nuvistor information


I have a series of various telemetry receivers - mostly DEI and Microdyne.
These are all solid-state as far as I know (the ones I've opened up). I
have a couple of oddball Microdyne 1100 series plug-ins (most came from Ron
Baublitz at US Surplus). These are VLF and a friend told me he thought they
might be for telephone interception. I think these came from one of the US
security agencies. The others are mostly S-band and were ex-NASA stuff. A
couple of the Microdyne mainframes in odd paint/anodize colors (all black
and one a dark blue). I think I have an old Nems-Clark somewhere - I'll
have to see if it has Nuvistors in it.

The other oddball - I think of them as odd since I was used to the classic
octal and the miniature 7- and 9-pin tubes - were the ones with more pins
and used in TV sets prior to the change to all solid-state. I don't recall
what these were called but they were fairly "squat" shaped and had more
pins than the miniature ones - maybe 11 or 12 pins? I found a photo of a
12-pin one here:

Have you ever seen these in anything other than vintage TVs? I don't think
Tek ever used them. Others on this list might know.

Steve H

On Thu, Jun 18, 2020 at 10:02 AM Jeff Kruth via <kmec=> wrote:

I have read several times in the thread that Nuvistors do not seem to fail
or get weak. This has not been my experience with them.

As one of the largest collectors of WJ & CEI "spook" radios, I have worked
on hundreds of pieces of their gear. The original company, Communications
Electronics Inc, founded by RE Grimm, used Nuvistors extensively in the
products made from the early '60's up into the mid to late 70's. (Along
with Mallory Inductuners!, more TV stuff) They used them in the 900 series,
the 700 series and the famous RS-111 and its military variant, the URR-52,
among others. BTW, NEMS-Clarke & Defense Electronics also used them in
their telemetry radios7 IIRC, the types they used were 8058, 7587 and 6CW4,
for RF amps, IF amps and LO, respectively. Some 7586's as well. The 8058 &
7587 were prone to getting weak and all reception stopped! I have also
found bad 6CW4's but rarely.For a long time 8058 were un-obtanium for me.
Many years after I really needed them I got a stash from cleaning out WJ.
Such is life. YMMV Jeff Kruth ________________ In a message
dated 6/18/2020 12:27:51 AM Eastern Standard Time, ka2ivy= writes: I read a history of them several months
ago, but can not recall where
I found it. The internal structure and envelope were manufactured in
the atmosphere. The rim of the ceramic base was metalized so it would
adhere to brazing. The components were then heated to outgas, then
brazed closed, in a very high vacuum chamber. A getter was not used
because the outgassing process cleaned the components very well. My
experience has been that they are very long lived. The circuitry in
consumer equipment may have also been designed so an aging Nuvistor
would still give good performance, I have never seen any change in
results from replacing a well aged one in a TV or FM receiver, even if
they tested marginally. The low voltage version used in a Tek scope,
however does get weak with time and can have catastropic effect on the
operation of the scope.

Bruce Gentry, KA2IVY

On 6/17/20 10:00 AM, snapdiode via wrote:
I just think Nuvistors are cool. Any information on how they were made
is interesting to me.
I've heard they were made in a high vacuum chamber with the assembly
machinery in the vacuum chamber.
There is no exhaust port on a Nuvistor.
I also wonder if there is a getter in there, or if the metal case itself
somehow acts as a getter.

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