I recently rescued a beautiful piece of RCA Test Equipment from the
dumpster....literally. I suspect this gear was in a Broadcast Studio
here on campus. I further suspect it was used to test distortion and
noise levels in an AM Broadcast Transmitter.

Here are the details. large D'arsonval meter at top center calibrated
in percent distortion and noise level. There are switch positions for
Oscillator out (Two tone or four tone??), Bridging, Phase (Four of
them a,b,c,d!), Calibrate and a Mode switch.
The back panel has inputs/outputs for audio, RF, Bridging and
Oscillator. Metal tubes inside four transformers. 6sN7's, Gas
Regulators, 6f8 etc.

Here's the clincher, outside of the Red RCA Logo there is absolutely
nothing to identify the model of this chassis. Searching the web
produced only iffy results.
It suggests maybe a B-9c??


Any ideas???


TIA,


Tony WA6LZH

"WA6LZH" wrote in message
...
I recently rescued a beautiful piece of RCA Test Equipment
from the
dumpster....literally. I suspect this gear was in a
Broadcast Studio
here on campus. I further suspect it was used to test
distortion and
noise levels in an AM Broadcast Transmitter.

Here are the details. large D'arsonval meter at top center
calibrated
in percent distortion and noise level. There are switch
positions for
Oscillator out (Two tone or four tone??), Bridging, Phase
(Four of
them a,b,c,d!), Calibrate and a Mode switch.
The back panel has inputs/outputs for audio, RF, Bridging
and
Oscillator. Metal tubes inside four transformers. 6sN7's,
Gas
Regulators, 6f8 etc.

Here's the clincher, outside of the Red RCA Logo there is
absolutely
nothing to identify the model of this chassis. Searching
the web
produced only iffy results.
It suggests maybe a B-9c??


Any ideas???


TIA,


Tony WA6LZH

My old RCA catalogues are boxed up at the moment and I
can't remember the model numbers. RCA did make a harmonic
distortion analyser for use mainly in broadcast proof of
performance testing. The oscillator provides a single tone
and is connected to the tranmitter audio input. The input to
the meter is usually from the detector output of the
modulation monitor. RCA made a companion oscillator and, of
course, a modulation monitor.
These date from the 1940's. At some point around the
1950's RCA began to offer General Radio station monitors and
distortion measuring equipment in their catalogues.


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Richard Knoppow
Los Angeles, CA, USA