A

Oscillator Coil--provides part of the antenna's resonant circuit and also a means of coupling the energy into the radiating wires (antenna).  Note it is set to maximum coupling.

 B

Quenching Gap--the energy dumped into the antenna will reflect back across the oscillator coil but will not have sufficient energy to jump the quench gap.  Thus the energy will stay on the antenna side and not be dissipated within the transmitter, resulting in a higher efficiency.

 C

Capacitor Box--with the spark gap sitting on top.  (Might be the transformer box E)

 D

Motor Starting Switch--required to bring the DC motor up to speed safely.

 E

High Voltage Transformer--steps up the generator's alternating voltage to the order of 10-20 kiloVolts.  The transformer would be heavy and most likely sat on the floor.

 F

Motor/Generator Assembly--converts the station's DC voltage to an AC voltage for the High Voltage Transformer.

 G

 Antenna Loading (Resonating) Coil--tunes the antenna system to the transmit frequency (wavelength) required.

 H

 Morse Key

 I

 Marconi 107a receiver/tuner.

J

  Possibly a #6 dry cell providing about 1.5 volts.  Most likely used to bias the receiver crystal so that it would be more responsive to the small signal coming from the antenna.

   The photo is one of Jack Bowerman's and serves as an excellent example of an wireless station from around 1910. The location is unknown. 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 operator would have to be very careful where his limbs were when transmitting.  Almost every exposed wire and connector in the left of the photo has enough voltage to give a severe shock or burn.  Not only that, there was enough voltage across the Morse key contacts to give a jolt.

 

   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 Fairbanks-Morse gas engine to spin the electric generator.  The next step was to get the transmitter's motor/generator going by manipulating the motor starting switch D in the photo. Within 10-15 seconds the generator would be up to speed and he need only tap the Morse key. Receiving would require moving the antenna switch to the receive position.  At the end of session he would reverse the procedure.  Ship stations were a patient lot and waited until the shore station got everything spinning and replied.

 

    At most stations fuel oil was rationed as one would never know if the supply vessel could keep to its schedule.  This station does have electric light, no oil lamps in view.  Often the electric lights ran on batteries which would be charged by the stations gas engine.

 

    In the dawning of the radio era there was no proliferation of stations on many different frequencies.  What ever came down the antenna wire to the detector would be heard.  As there were few transmitters, this wasn't a problem.  By the early 1910 period more stations were erected around the world and when a number of different transmit wavelengths came into use a serious problem ensued.   An operator would have a difficult time trying to hear one station while another, on different wavelength, was also working a third station.  It became necessary to provide some method of suppressing the unwanted frequencies impinging on the receiver. It wasn't long before receiver manufacturers built tuners to filter out frequencies other than the one required.  Even then, the receivers were still passive, whatever signal came down the antenna lead was used to drive the headphones clamped to the operator's head.

 

 

 

 

Spark Station Equipment