The Boonton uses a tube we call an "acorn" tube. It is a 955 triode. Still
plentiful and used in a few pieces of unretired test equipment. Also used in
some of the early WWII uhf equipment.
The Model 59 is still one of the very best grid dip meters and sells for about
$70 to $100. Because they are old and use vacuum tubes, you can occasionally
find them under the table at swap meets for $5 - if you are lucky.
I figure that the supply of 955 tubes will run out in about 300 years. At that
time, you can substitute an fet transistor in the circuit - if you can find an
fet transistor. Changing the voltage should make it usable with the fets.
Most grid meters do poorly on the highest range, but the model 59 keeps on
ticking.
73, Colin K7FM
-----Original Message-----
>From: hermans <on4kj@skynet.be>
>Sent: Feb 20, 2006 12:42 PM
>To: "'carl s.'" <carlseye@tampabay.rr.com>, Amps@contesting.com
>Subject: [Amps] RE : boonton 59
>
>Carl,
>
>The tube is what we called a "gland" (hope I remember well) quite a time
>ago we used that "gland" in UHF triode preamplifiers. Probably difficult
>to find in a industrial environnement. A special request would have some
>results I believe. Quite sure one or an other OLD TIMER still have one
>or more sleeping in their old drawers. Unfortunately I forgot the code,
>but i stil see it sitting in its 4 or 5 pins socket disposed
>horizontaly.
>Just a question, whats worth a Boonton grid dip nowadays ? 1976 last
>time I used the grid dip in our lab.
>Jos on4kj
>
>
>-----Message d'origine-----
>De : amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] De
>la part de carl s.
>Envoyé : dimanche 19 février 2006 15:41
>À : Amps@contesting.com
>Objet : [Amps] boonton 59
>
>
> I have acquired a boonton 59 dipper. In looking at the innards I am
>curious about the oscillator"tube" !! The unit works fine on all bands
>, but if that osc. fails, where would anyone ever find a replacement ???
>The "tube" has no markings on it and the "megacycle meter " is connected
>directly on top of the tube shell.
> Can anyone tell me anything about it ??
> thanks
> carl / kz5ca
>
>
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