Carrier Receiver Instruction Card

Introduction

The earlier topics described how the attack warning would be passed from Strike Command to the Carrier Control Points (CCP) located in Police Stations. Fallout and All Clear messages originated at the Royal Observer Corps Group HQ, again these were passed to the CCP. These would relay the message to the warning points by verbal messages over the carrier system. Immediately following the verbal message the CCP would operate the power siren by remote control.

In the base of the WB400 carrier receiver was a small draw containing instructions for the user. These included testing, battery replacement and fault reporting as well as how to respond to the three message types.

Instruction Card Drawer

The buff coloured card is 8 inches by 10 inches and folded twice to fit the drawer. This batch of 25000 cards was printed in June 1968. It is reproduced below, the layout matching that on the card as closely as possible. Various brands of browser render the layout differently.

Note - If you intend to print this topic.
Use the Browser's Menu - File / Page Setup... to set the paper to A4 Landscape mode and adjust the margins to 10mm (1/2"), check with print preview before printing.

UNITED KINGDOW WARNING AND MONITORING ORGANISATION INSTRUCTIONS FOR USE OF CARRIER RECEIVERS 1 Normally the receiver should be left switched off, except when undertaking the tests described in paragraph 4 below. In a war emergency, when instructed by the police or when it is publicly announced that the warning system is being activated, the receiver should be switched on and manned continuously until further notice. 2 To switch on turn the red volume control wheel until the "tick" signal can be heard clearly. The "tick" need not be unduly loud: speech and tone signals are always louder than the "tick". 3 To switch off turn the volume control to reduce the loudness and continue turning until the control clicks.
4 Tests	(a)	Weekly: Switch on for about 15 minutes and check that the "tick" is being correctly received.
	(b)	Six-monthly: The police will give instructions for routine tests at six-monthly intervals (and for any special tests which may be necessary at other times).
BE SURE TO SWITCH OFF AFTER EACH TEST 5 Warning messages, how received and action to be taken. Paragraphs 6, 7 and 8 on the centre sheet (pages 2 and 3) of this folder indicate how warning signals will be received, their meaning and the action to be taken to give public warning.
Page 1

BATTERIES 9 A spare battery is supplied and should be kept in a cool dry place with the seal covering the terminals intact until required for use. Batteries will normally be changed by the Post Office. 10 The battery in the receiver should last for two or three months continuous working, but it may be necessary to adjust the volume control from time to time to maintain the "tick" signal at normal strength. If the signal becomes too faint when the volume control is near its maximum position, the battery should be changed for the spare. 11 To change the battery, switch off and if the receiver is fixed to a table or shelf, remove the two fixing screws at either side. Turn the receiver on its side and remove the base by loosening the four screws within the rubber feet (a coin may be used to do this). Remove the battery and ease the snap fasteners from its terminals. Break the paper seal covering the terminals on the spare battery and press the snap fasteners on the battery lead on to the terminals (each lead terminal will fit only its correct battery terminal). Insert the new battery, tucking the leads in neatly beside the terminals. Replace the base of the receiver, tightening the four screws in the feet, and replace the receiver in its normal position. REPORT THE CHANGE OF BATTERY TO THE POST OFFICE IN THE SAME WAY AS A FAULT 12 Faults, interfering signals or any accident to the receiver, must always be reported immediately to the Post Office, in the same way as you would report a fault on the associated telephone, stating
	(i)	the number of the associated telephone
	(ii)	the nature of the trouble e.g. tick signal not heard, faint or affected by noise.
Page 4

Message (a)	How Received (b)	Meaning (c)	Audible Warning to the Public		Notes (f)
			Equipment needed* (d)	Action to be taken
			Equipment needed* (d)	(e)
6 Attack warning RED	Warbling note followed by spoken message--"Attack warning Red" then steady tone interrupted at 4-second intervals for one minute (this is the remote control signal).	Imminent danger of attack.	Hand-operated siren. Power-driven siren.	Hand-siren sound the alert (wailing note) for one minute. Power-siren. If the siren does not operate by remote control. sound the alert for one minute.	Hand-siren. Act as soon as you recognise the warning--Do not wait for it to end. Power-siren. Wait for five seconds after the completion of the spoken message then if the siren is not sounding operate the local control.
7 Fallout warning BLACK	Calling signal (high-pitched pip tone) followed by spoken message such as "Fallout warning Black, South Wales Twelve".	Imminent danger of fallout.	Maroon	If the warning message refers to your warning district fire the maroon.	Ditto. If the meter at your warning point shows that radiation has reached 0-3 Roentgens per hour or more, fire the maroon whether or not the warning message has been received.
8 Attack message WHITE	Calling signal (high-pitched pip tone) followed by spoken message, "Attack message White". then steady tone for one minute. (This is the remote control signal.) (In this form the spoken message relates to all warning districts; if only some districts are affected their numbers will be given, for example "South Wales Eleven and Twelve".)	All clear, no further threat of attack or fallout.	Hand-operated siren. Power-driven siren.	If the message relates to all warning districts or to some including your own:-- Hand siren--Sound the all clear (steady tone) for one minute. Power-siren--If the siren does not operate by remote control, sound the all clear for one minute. If the message relates to some warning districts only excluding your own-- Take no action.	BE SURE THE MESSAGE RELATES TO YOUR DISTRICT Hand-siren--Act immediately the spoken message is received. Power-siren--Wait for five seconds after the completion of the spoken message then if the siren is not sounding operate the local control.

* Issue only those public warnings for which the appropriate equipment is provided
Page 2	Page 3

Carrier Receiver Instruction Card

Introduction

Contents