B.C. Dominion Wireless Coast Station about 1910.

Spark Transmitter

Item
Description
A
Oscillator Coil--provides part of the antenna's resonant circuit and also a measns of cooupling the energy into the radiating wires. Note it is sett to maximum coupling.
B
Quenching gap. Keeps the antenna energy from getting back into the transmitter.
C
Might be the capacitor box with the spark gap on top.
D
Motor Starting Switch--required to bring the DC motor up to speed.  Lever is convenient to operator's hand.
E
Could be the high Voltage Transformer--steps up the AC generator's voltage to the order of 10-20,000 Volts. The transformer would be heavy and probably sit on the floor.
F
Motor/Generator Assembly--converts station's DC voltage to an AC voltage for the High Voltage Transformer
G
Antenna Loading (resonating) Coil--in series with the antenna lead.
H
Morse Key
I
Marconi 107a receiver

   The photo is one of Jack Bowerman's and serves as an excellent example of one of the original wireless stations. The location is unknown but is one of the first five stations. Transmitting and receiving apparatus are spread under and along the desk.  What you see, is what you got--the transmitter and receiver elements are all here--cutting edge 1910 technology.

   The wireless operator would spend his time sitting at this desk. The headphones would be against his ears and the receiver tuned to the appropriate frequency.  No power was required for the receiver as it was either spring operated (like an old Victrola record player) magnetic receiver or a crystal set. When the operator wished to transmit, he would remove the antenna from the receiver and connect it to the transmitter via a switching arrangement on the desk.  Next he would start the transmitter's motor/generator with the motor starting switch D in the photo. Within 10-15 seconds the generator would be up to speed and he need only manipulate the Morse key. Receiving would require moving the antenna switch to the receive position.

   Note how all the transmitter's 10-20,000 Volt wiring, especially around the 'E' area, is open to accidental contact by the operator's knees!

   Click on the left hand schematic to see a wiring diagram of a similar station. Most of the parts, except for the motor starting switch and starter box, are apparent in the photo at the top of the page. Other photos on this site show the large panel of heavy switches and meters next the operating position.


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