[Milsurplus] 991 neon lamp

[wa5cab at cs.com]

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
> 

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