[Milsurplus] 991 neon lamp

[J. Forster]

Yes, I found that too. Also they MAY be the same as 7AA, but I don't know.

-John

=============


> According to my database, the generic number for the 991 is NE-16.
>
> Another application was in the CGQ-43060 (TBX-8 radio).
>
> In a message dated 1/16/2010 10:40:58 AM Central Standard Time,
> n4fs at eozinc.com writes:
>> Of course I can see how that may well be true, as gaseous tubes have
>> been
>> used as broadband noise sources for years, especially the fluorescent
>> types.
>> Still, their ENR is doubtfully great enough to overcome a WWII front end
>> NF
>> and even the atmospheric noise prevalent there. Of course, zeners have
>> been
>> used as noise sources as well and the choice for state of the art noise
>> sources is a solid state diode. Heck, even a tube filament or a light
>> bulb,
>> generates considerable ENR above kT (where T=290K). In the 70's there
>> was
>> an
>> article in "Ham Radio" magazine as to how to make a noise source from an
>> incandescent light bulb. I built that circuit and used it to measure the
>> NF
>> of some of my UHF preamps. I personally have not experienced a noise
>> problem
>> by the 991s in the 348s that I used in the past. I suppose this is not
>> really OT in this forum. 73 - Mike
>>
>> Mike B. Feher, N4FS
>> 89 Arnold Blvd.
>> Howell, NJ, 07731
>> 732-886-5960
>>
>>
>>
>> -----Original Message-----
>> From: milsurplus-bounces at mailman.qth.net
>> [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Richard Brunner
>> Sent: Saturday, January 16, 2010 11:16 AM
>> To: milsurplus
>> Subject: Re: [Milsurplus] 991 neon lamp
>>
>> The 991 neon lamp is actually a voltage regulator rated 55 to 60 volts
>> at 2 ma, with 87 volts striking voltage.  They recommend changing at
>> 1000 hours.  My experience is they drift up in operating voltage with
>> use and time.  Ones I have tested regulated between 80 to over 100
>> volts.  I doubt an old one can be found in as-new condition, and would
>> use a Zener.  I also read that in the BC-348 receiver the 991 is a noise
>> source, and receiver performance improves when it is removed.
>>
>> Richard, AA1P
>>
>
> Robert & Susan Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
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