Unattended Transmitter Operation – The Automon

In radio station parlance, “The Transmitter” became the idiom that identifies the site and assemblage of equipment that includes a radio broadcasting transmitter and antenna that sends out waves of modulated electrical impulses of radio programs intended for reception by the public.

The Automon was invented by two RCA engineers in Montreal in the 50s to facilitate remote control of transmitters.

The first radio broadcasting transmitter to carry the human voice was invented and successfully introduced in 1900 by Reginald Fessenden. Since then, millions of transmitting stations of various types and sizes have dotted the earth. In everyday language “The transmitter” suffices.

By 1922, when 39 radio broadcasting licences had been issued by the government, transmitters could not be bought “off the shelf” or from a catalogue. You purchased the parts and built it yourself or hired a man to build one for you. Such a man was Bill Grant, a World War I veteran who served in the Signal section of the Royal Flying Corps and was operating a two-way communication service of the Canadian Forestry Patrol in High River, Alberta. Bill built a 50 watt transmitter which he moved into Calgary to ultimately become CFCN, “The Voice of the Prairies”. Bill also built and/or installed transmitters for two more Calgary stations, and others in Lethbridge, Red Deer, Edmonton and Saskatoon.

In the same year, Bert Hooper left the wireless room of the Pacific Ocean liner the Empress of Japan to take over the launching and all operations of CKCK, Regina, founded by the Leader Publishing Company, the city’s morning newspaper. Located on the roofs of the Leader’s two buildings at 1853 Hailton Street, were two steel towers for the antenna system. On the 5th floor below was a complete control room for the announcer-engineer, containing Lee Deforest equipment and a F-T type 2,000 watt transmitter made by the Canadian Independent Telephone Company Limited.

Less sophisticated and certainly less expensive was Barney Williams’ 50-watt CHWC transmitter that he hooked-up in 1926 on the top floor of Williams Department Store under the shadows of CKCK’s towers, to broadcast during the periods when CKCK didn’t. (Because of government policy at the time, two or more stations had to share the one frequency allocated to a city. Similar situations developed in other centres across Canada.)

In Wingham, Ontario (population 1,500). “Doc” Cruikshank, the founder of CKNX, built a tiny transmitter that he had assembled from a drawing in a Popular Mechanics Magazine and had mounted on a old “butter box” that he could carry from his home to his shop where he had started to repair radio receivers.

“Sparks” Halstead in Nanaimo. BC. also built and operated a small transmitter that he later took with him to Vancouver and used in founding CKWX.

In the early days, all of the technical apparatus for operating a radio station was contained in one room, to which was attached a room called a “studio” that was used for live programming.

However, in 1928 when Barney Williams wanted to increase the power of CHWC to 500 watts to equal that of CKCK, a new policy had been adopted by the government. New stations and any wanting to increase power to 500 watts had to locate their transmitter a distance of 10 miles from the heart of the city it was principally licensed to serve. This separated the transmitter from the studio and its control room. CKCK and stations in other cities already operating with 500 watts or more were spared the move.

Barney Williams solved his problem when he found an old cottage on a parcel of land on Number One Highway at Pilote Butte, 15 miles east of Regina that could be wired to the rural service of the Saskatchewan Power Commission, and to a pair of copper lines of Saskatchewan Government Telephones that would bring the programming from the studio in the city. Two tall telephone poles were “planted” in the ground outside the cottage and a wire strung between them, from the middle of which, using an insulator, was suspended a vertical wire (the antenna), connected to the transmitter below. The 500 watt transmitter was placed in one room of the cottage, leaving a kitchen, and a bedroom for the on-duty transmitter operator/engineer. There was a convenient out-house at the rear.

The transmitter duties were shared by the newly-hired chief engineer and an understudy who took turns week-about spending a seven-day stretch at the site. Fortunately, their attention was not required after 5.30 pm on Tuesdays, Thursdays and Friday and 9 pm on Sundays. as well as during alternating daytime hours when CKCK used the same frequency.

Barney now had to have a staff of four- two announcer-operators at the control room- studio in a converted travelers sample room behind the Kitchener Hotel, and the two engineers. Meanwhile, Bert Hooper at CKCK was able to carry out in one location all duties required of CHWC’s four.

Similar situations were occurring right across Canada. Regina and its two stations sharing the spot on the dial serves as the best example for explanatory purpose. Further detail is supplied under each station’s history on this webslte.

But every radio station transmitter had to have qualified attendants. When transmitters were installed outside the city, extra staff had to be found. Bob Lamb. likely the youngest .’technician” ever hired by a radio station and who grew up to become Chief Engineer of CFCN-Radio and CFCN-TV in Calgary, recalled that in another city during the Great Depression at the age of 13, he bicycled after school and on weekends to the transmitter to “baby-sit” it, earning 35 cents an hour. CFRB Toronto’s retired Chief Engineer. Clive Eastwood, recalls when he was a trainee that Ted Rogers Sr. employed 6 engineer-technicians at CFRB’s transmitter north of Toronto at Aurora.

Pioneer radio engineer, Bob Norton, whose career touched nearly every facet of Canadian broadcasting, recalled those days when transmitters had to be attended at all times. Remote control of transmitters was not allowed – in fact it was technically impossible.

Here are Bob’s own words spoken to a group of engineers attending a meeting of the Central Canada Broadcast Engineers Association. “You were required to log meter readings every hour. The really important thing was that you had to be able to shut down the transmitter on a moment’s notice, especially during the Korean War that started in 1950. The reason for having control of the transmitter was to prevent its signal being used as a navigational aid by any attacking force. The pressure was on to ensure that stations operated according to the rules. Thus, there was the need for remote control from the studio and monitoring, especially by a few stations who were not complying with the rules and did not have an operator on duty at all times at the transmitter.

Two engineers in the Broadcast Division of RCA in Montreal went into action. The first challenge facing John Collins and Bill Jeynes was how to get around the logging of transmitter meter readings. The rules were changed to allow “out-of-tolerance alarms” to be legalized, and you then needed only to log out-of-tolerance reports. A fail-safe relay was used to shut down the transmitter if control was lost with the studio through control-line failure. The answer was a plug-in relay”.

(At this point in his speech to the Engineers Association. Bob began using technical terms best understood by his audience, but we will stick to his script because how else can the true story be told?)

“The monitoring was accomplished using a Weston Sensitrol relay, which was a 50-micro-AMP meter, which could be set to close a contact if the reading was, say, 10% high, or another contact if it was 10% low. The unit in the control room at the studio had high or low lamps for the parameter in question. Also, an alarm would sound and the studio operator on duty could check which parameter was out of tolerance.

The various samples were obtained like they are today. Plate current samples would come from a small resistor connected via switches to a DC control pair to the Sensitrol meter­-relay in the studio unit.

These samples had to be fed as much as 20 miles on a DC pair – thus the need for a 50­-micro AMP meter. There was also the small problem of the resistance of the lines changing with the temperature. However, we were only interested in relative reading. The system was calibrated for different lengths of line between the studio and transmitter units. The system worked! – at least it did at CKVL Montreal when the tests were first made. In later years when remote control tests were being used by the CBC, they found they had less downtime. Bored transmitter technicians were not always messing around with the equipment. The saying, “if it ain’t broke, don’t fix it” was in use.

The monitoring receiver had to be a T.R.F. design to meet the frequency response requirement of 20 kcs and needed to have an RF output to drive the general radio mod monitor and the frequency monitor. These things were used to being fed from a transmitter. It took two 6AS7G tubes in parallel to get the required RF output from this monitoring unit. These were twin triodes. This part of the monitoring unit was an RF amplifier developing enough heat to require a cooling fan. It heated-up the studio rack it was in. All these receiver/monitoring units were replaced with a superhetrodyne RX and when an audio proof was needed, the monitor was taken to the transmitter to do it or left there in the first place and another method was used, such as a scope to measure the modulation at the studio.

The units returned to RCA were given to HAM operator friends who were very happy to have them. There were many useful components they could use in their HAM rigs.

John Collins and Bill Jeynes did a great job designing this equipment under time pressure. When they finished it they named it the “Automon”.

(Thanks to Bob Norton, we now have an understanding of how remote control at the studio of a broadcast transmitter several miles distant became a vital component in the day-to-day operation of a radio station)

But while the Automon did eliminate the need of on-duty technicians around the clock at radio transmitters there remained other hazards that needed to be overcome.

The studio and transmitter were connected by a dedicated and balanced telephone line that carried the station’s programming. Every Canadian station can recall at least one incident when programming sent to the transmitter by telephone lines was broken off due to various disruptions or interference with underground cables or those attached to telephone poles. A Winnipeg engineer found a baby carriage had snagged an overhead wire that crossed a busy street that could only have been riding atop a furniture mover’s truck. People with rifles often used the overhead cables and glass insulators for target practice and there are bulldozers and back hoes that play havoc with buried cables. Then, there are lightning strikes and vehicle accidents that knock down telephone poles.

To overcome the unreliability of telephone lines, engineers developed microwave equipment that transmits programming by line-of-sight from the top of the studio building (or if necessary a nearby higher building) to a receiving antenna at the transmitter. However, most stations still retain the telephone program line as back-up.

And when the normal supply of electrical current fails and black-outs occur, service to the public is maintained automatically by diesel generators at both the studio and transmitter.

Broadcaster ingenuity takes over when forest fires and overflowing rivers surround transmitter sites, and ice storms and aircraft knock down power lines and radio and TV antennas. Those stories became legends.

Lyman Potts & Robert Norton – 2003