| Wireless for the Warrior - Volume 2 |
Supplement No. 3 |
Wireless Set No. 48
Morse key assembly
Kelvin Barnsdale, ZL3KB, from New Zealand noted that there is a slight error in the circuit diagram drawing of Wireless Set No. 48 Mk. 1*(Figure 48-5 in Volume 2 of 'Wireless for the Warrior').
The arrow of the Send/Receive switch S7 is drawn wrong and must be reversed. The present position of S7 is 'Receive'.
When the switch is thrown into 'Send', the top and mid tip of the jack are connected resulting in Send/Receive relay S6A to be active.
The actual keying is done by the Morse key connecting the HT- and 12V+ to chassis.
Revised (part) circuit diagram Wireless Set No. 48 Mk. 1* Sender. See Figure 48-5 in Volume 2 of 'Wireless for the Warrior'.
Circuit diagram of Key and Plug Assembly No. 8A (ZA/US/1104) and Microphone Hand T17 (2B 1617).
Wireless Set No. 48 Vibrator Power Unit (NZ)
From John McKim of Christchurch, New Zealand, I received more information on the Vibrator Power Unit (NZ) for Wireless Set No. 48.
(See page 48-10 in Volume 2 of 'Wireless for the Warrior').
The Wireless Set No. 48 Vibrator Power Unit (NZ) permits the use of a 13.5/3 volt block instead of the battle battery when the set is used as an one man station.
The 13.5/3 volt block is much simpler to manufacture and has much greater tropical life.
The Wireless Set No. 48 Vibrator Power Unit (NZ) is housed in a metal box which fits into the space beneath the sender section of the Wireless Set No. 48.
It is fitted with a five-pin socket into which plugs the battery connection of the No. 48 Set.
In addition it has a lead which bears an octal plug to connect with the 13.5/3 volt block
and a second lead with a double-pole switch for controlling the filament supply and input to the vibrator section.
The 3 volt section is used only to supply the No. 48 Set filaments.
The 13.5 volt part of the battery block feeds the vibrator unit, producing about 150 volt HT; it is also used to energise the send/receive relay.
END
Wireless for the Warrior
