Frequency range: 300 metres and 600 metres  (Tunes P and Q respectively)
Power level: 1,500 watts
Comment: The disc discharger set used a rotary spark gap on the end of an alternator (see below).  It produced a musical note which was easier to hear through atmospheric noise.
Made by : Marconi UK

1.5 KW Disc Discharger Set.  This set was fitted in a ship's Silent Cabin. This sound proof compartment  is were noisy electrical apparatus was fitted.  Download image to enlarge. (Image courtesy Handbook of Technical Instruction for Wireless Telegtaphists)

This is the "business end" of the disk transmitting set. The electrodes, at position 'T' are renewable copper rods which can be fed down towards the disk studs to compensate for wear by turing the brass terminal heads. The stud plate 'S' is made from aluminum since this metal gives a better note spark than copper when both the sparking voltage and the power are low. (Image  courtesy Handbook of Technical Instruction for Wireless Telegtaphists)

Contributors and Credits:

1) Lewis Bodkin  <05bodkin555(at)gmail.com>

July 9/19