TYPE 4 TRANSMITTER
|DATE OF DESIGN||1912-1913|
|FREQUENCY RANGE||500 - 1500 kc/s on Transmit: 70 - 1500 kc/s on Receive|
|POWER SUPPLIES||Rotary Converter. Two types used both giving an output of 1kW AC @ 17 Amps 95-105 Cycles. The AC voltage is low because of the low DC voltage and the Frequency is low because the speed of the Converter is slow at 3000 revs|
|TYPE OF SET||SPARK|
|METHOD OF PRODUCING OSCILLATIONS||n/a|
|WHERE USED/FITTED||Type 4 is a medium powered spark transmitter/receiver which was fitted into all types of destroyers. Well capable of using the then full frequency spectrum to transmit and receive, destroyers were limited to 'D' Tune as their primary operating frequency which at the time was 1.4 Mc/s, was one of the highest HF [short wave] frequencies used in the Service. Approximate distance achieved was 200 nautical miles.|
The wavelength of 9.5LS to 91.4LS is 1.5MHz to 499 kHz. A wavelength of 14000 feet = 70 kHz. 'D' Tune or Wave @ 700 feet/LS 11.5 = 1.4 MHz
Look at this URL for a description of the office build wt office for destroyers.pdf
Note the different types of Crystals used to detect the incoming signal; Zincite, Tellurium and Carborundum.
The set above is used for Harbour Exercises/Manoeuvres.