Wireless of the Week - week 34

[Chris Suslowicz]

I'll keep a lookout for a C.A.V. lamp for you.

The WW1 "Lucas Lamp" had a wooden case, as you've got there, and was designed by one Captain Lucas (no relation to Joseph "Prince of Insufficient Light" Lucas, the automotive electrics manufacturer) as a replacement for the oil-fired "Lamp, Signalling 'B'". They work well and are a vast improvement on the oil lamp (with electric torch for the signaller) that they replaced.

Originally there was a standard 12-volt dry battery for the lamp, but this was replaced by 8 of the standard field telephone cells (X or S) connected in series.
(They were a stock item, the S (inert) cells could be stored for long periods, and it was one less thing that had to be supplied.)

The WW2 version was very similar, except that the British one used a pressed-steel case (Canada exported timber so continued with wood), and there was a spare battery case that contained 16 X (or S) cells - enough to make two complete 12V packs for the lamp.

Other versions:

1) Lamp, Daylight Signalling, Long Range - this used a larger (5") lamp and was powered by a 10 volt 16 amp hour accumulator.

2) Lamp, Daylight Signalling, Short Range (Mounted Services) - the cavalry version in two leather cases (for a balanced load).

3) Lamp, Daylight Signalling, Lightweight. Too late for WW2 and almost immediately obsolete. All fitted in a canvas satchel and the lamp had two handgrips (one with a push switch for signalling) and had a spigot to allow it to be mounted on a bayonet for the No.4 rifle. The battery compartment contained the usual morse key for use when the lamp was not being hand-held.

Apart from the "lightweight" lamp, all of these were intended for use as an alternative to the heliograph (at night or when cloudy) and fitted the standard tripod. (Stand, Lamp and Heliograph.)

The bulbs used are 'special', being mounted on a stalk to position them at the focus of the reflector (so the short and long-range lamps need different bulbs). You can run the lamp quite successfully from a pair of 996 lantern batteries - the internal cells are the same ('F' size) as the ones in the post-WW2 'X' cells.

(I must admit that I'd really like a lime light, but it would be difficult to assemble the rest of the kit (goatskin bags for the oxygen supply) and ordering large quantities of potassium chlorate would get the police taking an interest in me.)

Chris.