[GreenKeys] WE 3A Noise Measuring Set: Info??

[David Ross]

Roy & the gang -

  The DBRN you mention is DeciBels Relative to Noise.  'Noise' in the
U.S. telephone system is assumed to have a level of -90 DBm, so when
your test set measures +36 DBrn, you are actually seeing -54 DBm.  0
DBrn = one picowatt.

  The 'C-Message / 3 KC flat' module you mention is a filter.  C-Message
is an optional bandpass characteristic often used in noise measurements.

  Yep "BRDG/600/900" selects the meter's input impedance -  on BRDG it
is like 20K ohms or so.

  Sorry, don't remember what the NG setting is for.  I had one of the 3A
sets long ago, replaced it with an H-P 3551 when the 3A battery went on
to it's reward.

good luck with it
Dave Ross    N7EPI    ross@hypertools.com



Roy Morgan wrote:
> 
> I have just acquired a Western Electric 3A Noise Measuring Set.  This is
> good, because I have to find the source of noise in my home telephone wireing.
> 
> It is pretty self-explanitory, with summary instructions in the lid.  The
> thing measures "DBRN" which I assume means Decibels, Random Noise.  The
> controls include:
> 
> Function
>   - Batt (battery check_
>   - CAL (set the cal pot)
>   - Ng (don't know what this is - noise generator maybe?)
>   - BRDG  NM  (I assume it bridges the phone line for Noise Measurement -
> that is presents not a load but a high impedance):
>      - 600
>      - 900
> 
> WTG (A pull out and flip module that sets the weighting)
>   - 3KC Flat
>   - C-Message (what is this?)
> 
> Roy
>