[AMRadio] RCA Console

Bill Smith hbco2 at sbcglobal.net
Mon Mar 26 18:53:16 EST 2007

----- Original Message ----- 
From: "Rick Brashear" <rickbras at airmail.net>

> When the mighty RCA BT series were in regular use, was there a particular
> broadcast console that would take advantage of all the remote capabilities
> of the transmitter?

> Rick/K5IZ

By BA series you must mean the BTA- for AM transmitters and BTF- for FM
transmitters.  Consoles were identified by another series, for example BC-,
or by their numbers such as the 76-A, B and C.

In the earliest years when this equipment was state of the art, the FCC
required a transmitter engineer to be at the transmitter site during all
hours of broadcast.  He was required to possess a First Class Radiotelephone
license, and as part of his duties, he took meter readings every 1/2 hour
and adjusted the transmitter to maintain frequency and power output.  Many
stations of that era did not broadcast twenty-four hours a day, in fact most
signed off at or before midnight.   As a custom, all stations signed off and
signed on by proudly playing the Star Spangled Banner.

As a consequence, many studios were co-located at the transmitter site, and
station operators were put though a one-weekend wonder course to obtain a
First Class license.

Later on, in the late 50's, rules were relaxed somewhat and unattended
transmitters could be monitored by station metering at a remote studio.
Transmitter control and meter readings were still required each 1/2 hour.
By 1961, operators possessing a Third Class license were permitted to
operate the station and turn on and off the transmitter.   Meter readings
were still required, and a First Class licensed engineer was required to
work on the transmitter.

Many transmitter designs of this era were not designed to by operate remote
control.  Many had thermal-controlled overload circuit-breaker switches and
some contained fuses.  Tuning was accomplished by front panel controls.
Further, the FCC restricted transmitter equipment by certification; a
transmitter had to be type-accepted or specially certified to broadcast and
no electrical changes or equipment modifications were permitted.

Accordingly, companies such as Rust created rube-goldberg attachments which
could be bolted on the front of a transmitter such as a RCA BTA-1MX to
enable remote control.  They included big ugly motor driven articulated arms
which could grasp the lever of a circuit breaker and toggle the breaker on
or off.  The transmitter's metering circuits were tapped (but could not be
broken) to provide remote meter readings.  Stepper switches, synchronized
between the transmitter site and the remote studio, were used to select
metering circuits for remote display.  Additional motor driven devices were
bolted onto the front of the transmitter to allow plate tuning or increase
and decrease in power output.  With these modifications, the transmitter was
rendered as almost unrecognizable.

If a fuse failed, an engineer had to travel to the transmitter site and
replace it.

Later design transmitters such as the Bauer 707 provided integral remote
control capabilities.

73 de Bill, AB6MT
hbco2 at sbcglobal.net

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