Amateur radio early in the decade of the 1920's bore little resemblance to the
sophisticated equipment and operating methods used by the amateurs of today.
When
restrictions were lifted at the end of the first world war many amateurs, most of them for
the first time, got ready to go on the air.
Equipment could be, and usually was, extremely simple. An antenna, a tuning coil, a
crystal detector, and a pair of earphones sufficed for the receiver. The transmitter could
be equally simple. Besides the antenna, a Ford ignition coil delivering several thousand
volts, a key and a fixed spark gap would get you on the air. In this simple transmitter,
the characteristics of the antenna determined the frequency. Usually there was no tuned
circuit at the transmitter itself.
The more advanced amateur used a one-tube receiver usually without amplifiers. Loud
speakers were unknown in the early twenties. The transmitter was much more elaborate than
the spark coil type. A high-voltage transformer drawing as much as a kilowatt from the
line was shunted across the secondary by a glass plate capacitor able to withstand a
voltage of I 0,000 or more. A rotary spark gap was connected in series with the capacitor
and to what was called an oscillation transformer. This was just a primary and secondary
coil to provide a match to the antenna. The rotary spark gap improved the transmitted note
and also narrowed the band width slightly as compared with the fixed spark gap.
Continuous waves using tubes had already been developed and were being used by
commercial stations and the armed forces, but at first amateurs did not favour this
method. Due to heating of the tube and its circuit components, oscillators, which
determined the frequency, were very unstable, drifting in frequency to the extent that it
was extremely difficult to hold a signal once contact was established. Furthermore, all
C.W. signals sounded the same, making identification difficult amongst several drifting
signals. Also, it was very difficult to arrange a schedule with another operator because
of the extreme narrowness of the signal. Modem transceivers with exact knowledge of the
frequency settings make scheduling comparatively easy.
Spark on the other hand has several advantages from the amateur's point of view. It was
cheap and simple to assemble. It could be received with a crystal detector, and its
broadband characteristics were actually what the amateur wanted. When he turned on his one
kilowatt transmitter, everybody within range heard him. With a kilowatt of power and a
rotary spark gap, a transcontinental range was not at all unusual. In fact Ted Rogers,
3BP, located in Newmarket Ontario, using spark was heard in Scotland during tests
conducted by the ARRL.
A number of factors determined the tone or note heard from a rotary spark gap
transmitter and its associated circuitry. The transformers secondary, the capacitor
shunting the secondary, the number of teeth in the rotary wheel, and the speed of the
motor driving the wheel all determined the characteristics of the transmitted note such
that no two transmitters sounded the same. You could copy your man under other signals without too
much trouble. The tone from a rotary spark gap fed from a 60 Hertz source was very musical
and quite pleasant to hear. Listening to several signals coming in at once sounded much
like a pipe organ. It was no wonder that amateurs were reluctant to give up spark
transmission in favour of C.W.
Some of the more progressive amateurs used an improved type of spark gap. In this one
the wheel was driven by a synchronous motor, and the stationary electrodes mounted on an
insulated arm, could be rotated around the axis of the wheel to a point where the gap
would discharge the capacitor when its charge had reached its peak value. By this means,
the radio frequency wave-train that resulted had a much lower decrement than would be the
case with the older free-wheeling gap, thus approaching a continuous wave. The band width
was noticeably narrower.
A few tube types were available. The Audiotron, Electron Relay, and a Marconi type were
relatively inexpensive. The Audiotron was the most popular. It had no base and required no
socket. It was constructed in a standard test tube and had two filaments (one was spare).
It could be mounted on a panel with four terminal posts. All tube types were triodes.
Most of the Toronto amateurs were members of the ‘Wireless Association.’
Meetings were held in the physics building at the University of Toronto. Sometimes it also
served as a swap shop.
When I was about twelve years old and still going to elementary school, I acquired an
old copy of an Electro Importing Company catalogue. It was fascinating reading, containing
such items as Murdock and Holzer Cabot earphones, crystal detectors, tuning coils, and
loose couplers etc. There was even a page devoted to parts for television experiments. I
used to read the catalogue in school when the teacher wasn't looking. I lived in Toronto
at the time, and it wasn't long before I found that the goodies described in the catalogue
were available in the city from several stores. One store, Rogers Electric just west of
Bay Street on Queen had a window full of tuning coils and couplers, earphones and crystal
detectors as well as many other interesting items. Another store, Paquins was on Queen
Street West near Bathurst Street. Still another, the Vimy Supply Company on College
Street.
Incidentally, a licence wasn't necessary at first. We just used our initials for a call
sign.
My antenna system happened to be noticed by a fellow amateur, Ed Davis. Ed lived down
the street from me. By daily talks over the air we soon became familiar with the Morse
code. Later when we both had oscillating tube receivers, we found that we could work each
other using the R.F. output of our receivers and inserting a key in the antenna lead. The
first transceivers I guess.
When licences became necessary, both Ed and I applied together. Ed got the call 31Z and
I got 31V. No exam was required. All you needed was a dollar. The licences were issued by
the Department of Marine and Fisheries. A few years later I was able to get the call 3CR.
Prefixes were not used until later. Some of the names and calls that I still remember were
Ed Davis 3IZ, Frank Godfrey 3EO, the Fowler brothers, Ed 3DE and George 3CN, Gordon McLean
3GE, Bill Choat 3CO, Keith Russell 9AL, Ken Wood 3EI, Bill GiIlard 3JC, Ted Rogers 3BP
(the
father of Ted Rogers of Rogers Communications), Howard (Blackie) Taylor VE3ABZ
and Fred Hammond 3HC. Some names whose calls I don't remember were Gordon Pipe, Fred
Taylor, Ed Pigott, and Bill Munslow.
Like most teenagers I started out with the Ford ignition coil, a fixed spark gap and a
crystal detector receiver. Usually there was someone to talk to who had similar equipment.
The older fellows with more powerful transformer rigs would not always answer if we sent
out a QST or CQ.
Eventually I graduated to a one-kilowatt transformer, rotary spark gap, and a tube
receiver, but the fun didn't last. Radio broadcasting was becoming very popular. Many
people were listening to KDKA programs every night and they regarded us kids as pests not
to be tolerated. A letter to the editor in a Toronto newspaper mentioned several names and
calls including mine, and described us as unreasonable kids.. My father noticed this item,
became very upset and told me to dismantle my transmitter at once. However he did help me
to finance a C.W. transmitter so that I was able to operate in peace and, of course get
some real DX.
It wasn't very long after that when spark was prohibited entirely for amateurs although
it was still used for ship-to-shore communications.
When I became eighteen years old I obtained a commercial licence and operated spark
transmitters aboard ship until the late twenties.
