[BC] WGUN Westinghouse

[Johnson, Richard]

On Wed, 28 Mar 2007, Scott Fybush wrote:

> Bob Groome wrote:
>> So did KMOX, WWWE(WKYC-WTAM) and WHAM
>>
>> I've seen them but don't think any of the are
>> functional. Not sure any of them are even still
>> ther.
>>
>> Bob
>
> I was just talking to the WTAM guys this morning...would have asked
> about their Westinghouse if I'd known!
>
> WHAM's Westinghouse was removed a few years ago when they put in a DX50.
> (Sadly, I never got to see it!)
>
> There was one at KEX until a few years ago, too, but it's gone now.
>
> The only functioning HG I've seen in recent years is at WOWO.
>
> http://www.oldradio.com/archives/stations/ccs/wowopix.htm
> http://www.fybush.com/site-021128.html


The most impressive AM Radio installation I ever saw was a
mere 10 kilowatt. However, it was a "composite," read home-
brew rig at radio station WTYM in East Longmeadow, MA. Its
call letters have changed to WNHP and it now runs only 3 kW,
while it used to run 10 kW on 1600 kHz.

The transmitter was built into the basement of the building.
It consisted of four screened-off areas in which timber framing
was covered with "rabbit-wire." The screened areas were for
the final amplifiers and drivers, the modulators and drivers,
the RF exciter, and the audio exciter. The HV power supply was
in the open as were the modulator components.

The final amplifier tubes and the modulator tubes were all
of the same type (unknown) and were nearly as tall as a man
with a grid connection on the side and a plate connection on
the top. The filaments of these tubes were supplied by
four separate motor-generators as was the bias supply.

Both the modulators and the RF finals were push-pull triodes.
The RF finals used crossover neutralizing capacitors that
were large cylinders. The output used fixed capacitors with
variometer tuning plus a gigantic counter-balanced swinging-
link for output loading. The grid circuit, which was the
plate circuit of the preceeding stage (also triodes) had
the largest air-variable capacitor I ever saw. It was the
size of an automobile! I have seen many transmitters including
gigantic Western Electric machines. This little 10 kW rig
was the largest I have ever seen. It was truly impressive --
plus it was a beautiful work or art.

Earl Hewinson was the Chief Engineer and he would upgrade
it periodically to use the "latest technology." For instance,
the RF exciter used a pressure-mounted crystal in a
thermostatically controlled wooden box. It was maintained
at 60 degC using a thermometer that contained some contacts
that would open if the temperature got too cold. This
reverse sensing was accommodated using a relay that made
a loud noise. Even in the studio above, one could occasionally
hear the clicks of that relay. When I completed the Type-
Acceptance of my transmitter I built at WDEW (read my book),
Earl asked me to make a crystal oscillator substitute for
his wooden box. I made one, using one of those "new fangled"
AT cut vacuum-mounted crystals invented by Northern
Engineering, just like I used in my transmitter. The
oscillator was a 12BY7 with the same as an untuned buffer.
This was normally used as a TV video amplifier. Its low feedback
capacity made it ideal for the application. The buffer fed a
6146 for Earl's transmitter. These were the first "modern"
tubes to go into that rig! Earl got the station manager
to pay me $50.00 for the design. That was not too bad for
one day's work of an eighteen year old! That's about the
same as $500.00 nowadays. I made lots of money with a
Greenlee punch!

Cheers,

Richard B. Johnson
Project Engineer
Analogic Corporation


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