The objective of the PREPCOM radio coms standard is to maximise the effectiveness of UK based survivor radio stations following a major disaster in which conventional telecommunications have ceased.
For easy mnemonics the standard is the RULE OF 3S
3 is the important number. Remember it!
The 3 parts to the Standard are:
- 1/3:WHEN (Time coordination so we all know WHEN to call and listen)
- 2/3:WHERE (Frequency coordination so we all know WHERE to call and Listen)
- 3/3:HOW (Radio set-up so that everyone’s transmissions are compatible)
What’s this document for?
It is intended that this document be printed and stored in a water and light-proof pouch which is to be kept with stored radio equipment intended for disaster communications.
PART 1/3 =WHEN
Everybody looking to communicate needs to coordinate the time at which to do so.
By coordinating times and limiting operational time window precious electrical power will be conserved
Rule of 3s again:
Start communication sessions On the hour
Every 3 hours (starting 00.00h)
For 3 minutes calling and listening, if nothing heard, close the station and try again at next scheduled time.
Note, if a contact is made it is good practice to move communications to another channel / frequency so that the emergency calling channel is freed for other users
There is no requirement to end it after the magic 3 minutes, it can continue as long as required, but bear in mind power consumption.
PART 2 =WHERE
Where relates to Frequency coordination so that everyone is also communicating on compatible frequencies, failure to coordinate frequency is like not knowing the direction in which to flash a torch to signal to someone at night. We need to know exactly where to send and where to look.
Rule 2 is broken into two parts 2a for simple License-free transceivers ( CB and PMR446 walkie-talkies), whereas 2b Ham is a full version incorporating both license-free and Ham frequencies.
PART 2a =WHERE License free
So for license free, the RULE of 3 continues. Set your radio to one of the following:
• FM only CBs = Channel 03 English band
• SSB capable CBs = Channel 33 USB EU CEPT Band
• PMR446 (kiddies type walkie-talkies) = Channel 03 (CTCSS/ DCS code turned OFF)
PART 2b/3=WHERE Full version
UK Emergency Frequencies:
3.663 MHz LSB Weekly RAYNET news Every Sunday 0830 local time
3.760MHz LSB Emergency RAYNET Centre of activity
7.023MHz CW NVIS low-power Morse Code Centre of activity
7.110MHz LSB Emergency RAYNET Centre of activity
14.300MHz USB Emergency RAYNET Centre of activity
21.360MHz USB Emergency RAYNET Centre of activity
27.62125MHz FM CB UK 27 Ch 03 Emergency Channel*
27.555MHz USB CB FREEBAND ( Illegal frequency) but well populated.
27.335MHz USB CB EU CEPT Ch 33 Emergency Channel*
51.210MHz FM NB RAYNET Emergency Centre of activity
51.950MHz FM NB RAYNET Emergency Centre of activity
To 51.990MHz FM NB RAYNET Emergency Centre of activity
144.260MHz USB RAYNETEmergency Centre of activity
144.625MHz FM NB RAYNET Emergency Centre of activity
144.675MHz FM NB RAYNET Emergency Centre of activity
144.775MHz FM NB RAYNET Emergency Centre of activity
145,200MHz FM NB RAYNET Emergency Centre of activity
145.225MHz FM NB RAYNET Emergency Centre of activity
433,700MHz FM NB RAYNET Emergency Centre of activity
433,725MHz FM NB RAYNET Emergency Centre of activity
433,750MHz FM NB RAYNET Emergency Centre of activity
433,775MHz FM NB RAYNET Emergency Centre of activity
446.03125MHz FM NB RAYNET PMR446 Ch3 emergency channel***
* License free: Rule of 3s = CB Ch 03 FM every 3 hours, on the hour for 3 minutes (staring 00.00h)
** License free: Rule of 3s = CB Ch 33 USB every 3 hours, on the hour for 3 minutes (staring 00.00h)
*** License free: Rule of 3s = PMR446 Ch3 (CTCSS/DTS OFF) every 3 hours, on the hour for 3 minutes (staring 00.00h)
PART 3/3=HOW to set up the radio and transmitting antenna
3.1 Identifying and setting the operating MODE of your radio
In all descriptions there are annotations FM/USB/LSB/FM NB. These are the different TYPES/ FORMATS/MODES of signal that radios can transmit.
It is essential that sending and receiving stations are using identical transmission TYPES otherwise they will not be able to hear one another even if transmitting and receiving on the same frequency at the same time.
Look at your radio: If it has a MODE knob it will allow you to select the modes required. If it does not have a mode knob and it’s a CB it will almost certainly be FM only. This should be confirmable by looking for a label or stamp of conformity on which the letters FM will be shown.
PMR446 equipment is only manufactured in FM variety so no choices to make.
3.2 POLARITY of your antenna.
For CB the antennas must be vertical
For PMR44s antennas must be vertical
For Ham frequencies below 28MHz antennas must be HORIZONTAL
For Ham frequencies in FM mode above 28MHz antennas must be VERTICAL
For Ham Frequencies in LSB/USB mode above 28 MHz antennas must be HORIZONTAL
Note: This document is available for download from the comms area of the files site.