by J.V. Fitzhugh, W5VL (SK)
San Antonio, Texas
Written in 1992
N7NET’s note: One day, while chatting on two-meters, I answered the call of a ham passing through town on a bus. He was an active member of the U.S. Army Band on tour. He was one of many who were aboard a chartered bus that was passing through Eugene, Oregon en route in the Bay Area where they were scheduled to perform. The musician’s name and call have slipped into my shadowy past. But his father K5VL, a veteran operator of the spark gap days, became the subject of our QSO. Before the year was out W5VL had sent me a fistful of audio tapes filled with memories from his past, which, in turn, were published in QNCW
In 1992, when this story was current, Mr. Fitzhugh was 99 years young.
Seventy years ago Spark Gap transmitters and Galena crystal receivers, with their infamous “cat whisker” tuning were the heart of early stations appearing on the 200-meter band.
Before the development of vacuum tubes, receivers consisted of only a few major components:
1. A large, wire coil with a narrow strip from which the insulation had been removed. A sliding, shorting bar, capable of contacting the bare strip at a given point, enabling the operator to change the electrical value of the coil at will.
2. A smaller coil capable of providing loose or tight coupling with the larger coil.
- A Galena crystal.
- A piece of small-gauge spring steel wire called the “cat whisker.”
By moving the cat whisker about the surface of the Galena crystal a sensitive area could eventually be located. For a time this was the only method for capturing and amplifying radio frequency signals.
When a ham turned on his spark transmitter he began transmitting before the motor, which turned his rotary gap mechanism, had reached operating speed. This caused the sound of his signal to increase, creating a rise in the tone as the motor revolution increased. During a QSO the operator might choose to switch off the power to the motor, causing the frequency of his signal to diminish, giving his transmitted signal a melodic quality.
Crystal receivers of that era had little selectivity. When an operator tuned in a station of his choice, numerous other stations were also heard. The sound resembled an orchestra tuning up prior to a concert, at first one station changed tone, then another, and still another by switching their motors on or off. It is regretful that recording equipment was not available during that period.
Electrical grounding of equipment was no less important then it is today. However, the task was accomplished in a much simpler fashion. Radial grounding wires where not yet in use. Instead, a single wire attached to a metal rod which was driven into the soil was sufficient for receiving purposes. Many amateurs attached their grounding wires to the plumbing. While this was satisfactory for reception, grounding the transmitter in such a manner often dispersed radio frequency interference over a larger area, creating problems even more difficult to solve.
My Spark transmitter was of the “open” type. By not enclosing the sparking area I allowed a very loud arcing noise to escape the sparking area. It often made exploding sounds and I was very fortunate not have had complaints from my neighbors.
Eventually, I went to the home of a friend who demonstrated his transmitter, which was enclosed. Also, he had a darkened glass in the front of the enclosure, allowing the operator to watch the spark without dazzling his eyes. I found both features an improvement over my spark system.
I was only twelve years old at the time and knew so little about the equipment I was operating. I was unaware that RF was finding its way into the motor windings of my rotary gap. After a few weeks the motor began to hobble, and I was unable to keep it running smoothly. After removing the motor housing I could see splattering of solder everywhere, indicating that RF had ruined the field winding. The defective motor curtailed my spark activity, but I continued receiving.
When radio was very young there were no commercial broadcasting stations operating on the 200-meter band, but in engineering circles the possibility of voice transmission was a serious consideration.
Flemming had created a diode-type tube. Doctor Lee DeForest followed, shortly after, with a vacuum tube featuring the first control grid.
Apparently, one of the first experimental voice broadcasts took place in Schenectady, New York, for the purpose of testing the public reaction. One night I nearly jumped out of my chair when a human voice came over the code frequency to which I was listening.
Soon, broadcast stations were operating across the country, and amateurs shared the band with them. The arrangement resulted in total chaos, with the hams taking the larger part of the blame. Tense discussions between Congress and the amateur radio operators resulted. The subject became so heated that amateurs were on the verge of loosing transmitting privileges, entirely. Had it not been for Herbert Hoover, the Director of the Department of Commerce, and pressure from the American Radio Relay League we might have lost our amateur privileges all together.
The Federal Communications Commission came into existence in the early 1930s. With it came rules and regulations. Eventually, the 200-meter band was given over to the AM broadcasters, where they remain to this day.
QNCW, The QRP CW Journal 