How To: New Wire-5 project (Bergeron)

[Chris Suslowicz]

(One practical demonstration of Boob's Law[1] later...)

Switchboard UC 6 line with battery and Box, Accessory, Switchboard UC 6-line containing 7 pulley weights and cords; operator's Telephone, Hand, No.2; Night Bell and connector. Weight 35 lb. 6 oz.

The current for the switchboard is provided by a battery of three cells (Cells, Dry, X, Mk.II; or Cells, Dry, Inert S, Mk.I) contained in a removable box behind the line units in the back of the case, connections being made to the battery box by means of plugs and cords. Terminals are provided on the line terminal panel at the back of the switchboard for the connection of an external battery if desired.

(Pulley weights are apparently optional for the 6-line version.)

The battery box has sockets on the end to take the two plugs from the switchboard.

Best regards,
Chris.

[1] You always find something the last place you look - I think I found manuals for everything between the pre-WW2 "Mark 236" and the postwar 40/160 Line Exchange before the Switchboards UC 10-line and 6-line pamphlet turned up!

[Robert Bergeron]

Thank you very much Chris ! 4.5 Volts then . The field phones run on the same voltage i assume ? Boob’s law ?

[Chris Suslowicz]

Hi Robert,

Boob's Law - see footnote [1] on my previous post.

Field Telephones for WW2 Commonwealth forces would be the D Mk.V for front line forces, Telephone Set 'L' for Linemen, and Telephone Set 'F' for higher formations (basically an office telephone for people with desks). All of those ran on 3 volts from a pair of 'X' or 'S' cells. Switchboards for higher formations would be the Switchboard F&F (Field & Fixed)which could support 20 to 60 lines and could operate with three switchboards in parallel as a combined unit.

Switchboard UC "Universal Call" supported buzzer and magneto signalling.
Switchboard F&F is magneto only.

Telephone set D Mk.V was buzzer call but buzzer or magneto ring
Telephone set 'F' was originally buzzer and magneto signalling but the buzzer was replaced by an induction coil (microphone transformer) later on (for better audio quality) and became magneto only.
Telephone set L was magneto signalling (only).
(There may have been some earlier (Post Office 110) telephones still used by linemen, but the 'L' was rather better.)

(Plus the various Remote Control Units (Canadian) and the British 'E' could connect to switchboards as magneto telephones, of course.)

All the manuals are available from the WS19 website - I think I scanned most of them.

Best regards,
Chris.

[Robert Bergeron]

Thank you for your detailed answer Chris - Wanted : Look at pictures . I want to set up an artillery comm truck so i need these to complete the CES. Photo credit : Bruce Parker .

[Robert Bergeron]

Built a homemade Tannoy speaker today to listen to the WS No 19 set . Still looking for an amplifier to connect to one of the drop plugs but the search is narrowing .

[Chris Suslowicz]

Originally Posted by Robert Bergeron

Built a homemade Tannoy speaker today to listen to the WS No 19 set . Still looking for an amplifier to connect to one of the drop plugs but the search is narrowing .

Looks good. Does the Tannoy speaker have a transformer attached to it?

There's a discussion of the Sexton SPG setup with Control Unit 190 that uses the WS19 IC amplifier to drive the loudspeaker. (This is not what you want, as it will be much too loud, being intended for 25 pdr gun crew instructions in a confined space, and the gun crew did not use headsets.)

It may provide a few pointers on how to do it, though.

(I recently bought a Canadian ALS No.2 Mk.2 loudspeaker (with added woodworm) that has the lower pair of terminals for the WS19 IC amplifier drive. That uses the 30 ohm tapping on the transformer (the ALS uses a higher impedance drive - I think what was known as "100 volt line" - to allow the use of field cable without excessive losses), and the loudspeaker switch selects 'A' 'Off" and 'B' on the Control Unit 190, with a resistance in series to prevent overloading the amplifier. (I intend to draw out the circuit diagram from the photographs in that thread, and match it with the parts list from EMER Tels FZ-256/3 in order to (a) see how it is supposed to work, and (b) construct something vaguely similar.)

The Sexton appears to be fitted with Control Unit No.2 for the Wireless Op,
No.190 for Commander (droplead) and gun crew (loudspeaker), plus a Junction Distribution No.3 for the driver intercom - though I need to check that.

On the move only the commander, wireless operator and driver would have headsets (intercom and wireless), maybe with the loudspeaker on when required. Deployed they could use wireless or lay wire and use the ALS for the GPO and four guns. (I think - I'm not an artillery person.)

Best regards,
Chris.

[Bruce MacMillan]

Originally Posted by Chris Suslowicz

There's a discussion of the Sexton SPG setup with Control Unit 190 that uses the WS19 IC amplifier to drive the loudspeaker. (This is not what you want, as it will be much too loud, being intended for 25 pdr gun crew instructions in a confined space, and the gun crew did not use headsets.)
Best regards,
Chris.

The Canadian Army did approach PYE about producing a speaker for the 19 set. Quote was only a few £ (pounds, quid) per speaker. At that price it must have been only a box, speaker and maybe matching xfmr. They must have thought this was adequate enough volume to be useful. If you're not broadcasting to the neighbourhood you don't need much power.