1.5 kw Combined Telegraph and Telephone Set, Cabinet Type.SPECIFICATIONS
Model: For some reason, Canadian Marconi did not assign model numbers to their equipment in the early years so the title of this web page becomes the model number.
Modes: CW, ICW, AM (ICW was also referred to as "Tonic Train" in those early years.
Transmitter frequency Range: 1,200 to 3,000 metres (250 to 100 KHz respectively)
Receiver frequency range: 300 and 3,000 metres. (1,000 KHz to 250 KHz respectively
Power output: 1.5 kw
Antenna current: 10 amps
Transmitter Tubes: 3
Receiver tubes: 7
Mains power: Via alternator
Typical distances: 500 miles using CW' For MCW, 350 miles; 250 miles on telephony
1) Broadcast station CKCD in Vancouver BC is known to have used this type of transmitter. It was also used in marine applications.
2) The name FONETER appears in one of the captions for the Cabinet Telephone set.. In the Swedish language, foneter means "phonic".
|1,5 kw Cabinet type transmitter. The transmitter is divided into two parts. The transmitting valves were mounted on a panel at the left while the receiving components were situated on the right side. The transmitting tuning inductance and the reaction coil are supported by insulators mounted to the top of the cabinet. At the right top is the Marconi (UK) type 70 tuner with the type 55 detector amplifier below it. (Image courtesy HIT)|
simplified schematic of the transmitter portion of the cabinet style transmitter.
The highlights of this circuit are:
Valve RV provides half wave rectification. In CW mode, only valve OVA is used as the oscilator .Valve CV gets disconnected from the filament lighting transformer FOR ICW operation, valve CV is flashed up in addition to the oscillator valve OV.. When wireless telephony mode is used, the microphone' 'M'' and the transformer that its connected to , modulate control valve CV. (Schematic courtesy HTI).
|This is the antenna changeover switch between the receiver and the transmitter, (Courtesy HTI).|
|This 1.5 kw set was likely imported from Marconi UK by Canadian Marconi for sale in the Canadian marketplace. Not sure about the source of this ad. It may have have been published in Yearbook of Wireless Telegraphy 1920 (Submitted by Lewis Bodkin)|
Contributors and Credits:
1) Lewis Bodkin <5bodkin555(at)gmail.com>
2) Handbook of Technical Instruction for Wireless Telegraphists (HTI)
3) Handbook, and Canadian Wireless , Aug. 1921, and May 1922.
4) Radio News of Canada