<s>
Citizens	B-Application
band	I-Application
radio	I-Application
(	O
often	O
shortened	O
to	O
CB	B-Application
radio	I-Application
)	O
is	O
a	O
system	O
of	O
short-distance	O
radio	O
communications	O
between	O
individuals	O
on	O
a	O
selection	O
of	O
40	O
channels	O
within	O
the	O
27-MHz	O
(	O
11	O
m	O
)	O
band	O
.	O
</s>
<s>
In	O
the	O
United	O
Kingdom	O
,	O
CB	B-Application
radio	I-Application
was	O
first	O
legally	O
introduced	O
in	O
1981	O
,	O
but	O
had	O
been	O
used	O
illegally	O
for	O
some	O
years	O
prior	O
to	O
that	O
.	O
</s>
<s>
In	O
December	O
2006	O
,	O
CB	B-Application
radio	I-Application
was	O
deregulated	O
by	O
Ofcom	O
and	O
it	O
is	O
now	O
licence-free	O
.	O
</s>
<s>
Although	O
the	O
use	O
of	O
CB	B-Application
radios	I-Application
in	O
the	O
UK	O
has	O
declined	O
from	O
its	O
peak	O
,	O
it	O
is	O
still	O
popular	O
,	O
especially	O
with	O
the	O
farming	O
community	O
,	O
Land	O
Rover	O
owners	O
and	O
Mini-Cab	O
services	O
.	O
</s>
<s>
CB	B-Application
radio	I-Application
was	O
first	O
introduced	O
into	O
the	O
United	O
Kingdom	O
around	O
1968	O
.	O
</s>
<s>
As	O
citizens	B-Application
band	I-Application
radio	I-Application
has	O
been	O
advertised	O
in	O
the	O
US	O
since	O
before	O
1962	O
,	O
it	O
is	O
possible	O
that	O
a	O
number	O
of	O
these	O
radios	O
were	O
brought	O
into	O
the	O
UK	O
and	O
used	O
illegally	O
.	O
</s>
<s>
In	O
the	O
period	O
1976	O
–	O
1978	O
,	O
CB	B-Application
radio	I-Application
in	O
Britain	O
was	O
much	O
popularised	O
by	O
novelty	O
hit	O
songs	O
and	O
its	O
use	O
in	O
the	O
film	O
Convoy	O
and	O
the	O
usage	O
of	O
illegal	O
CB	B-Application
radio	I-Application
peaked	O
in	O
1980	O
.	O
</s>
<s>
The	O
UK	O
Government	O
eventually	O
legalised	O
CB	B-Application
radio	I-Application
,	O
and	O
on	O
2	O
November	O
1981	O
a	O
CB	O
service	O
was	O
introduced	O
on	O
a	O
frequency	O
band	O
and	O
offset	O
that	O
is	O
incompatible	O
with	O
the	O
imported	O
American	O
radios	O
.	O
</s>
<s>
Given	O
that	O
virtually	O
all	O
illegal	O
CB	B-Application
radios	I-Application
were	O
contraband	O
,	O
this	O
concession	O
required	O
the	O
licensed	O
amateur	O
to	O
pay	O
outstanding	O
import	O
duty	O
and	O
VAT	O
.	O
</s>
<s>
As	O
of	O
8	O
December	O
2006	O
,	O
a	O
licence	O
is	O
no	O
longer	O
required	O
to	O
own	O
or	O
operate	O
a	O
CB	B-Application
radio	I-Application
providing	O
it	O
complies	O
with	O
one	O
of	O
the	O
3	O
type	O
approval	O
conditions	O
currently	O
permitted	O
by	O
Ofcom	O
:	O
FM	B-Application
only	O
,	O
4	O
watts	O
power	O
output	O
and	O
operating	O
on	O
either	O
or	O
both	O
UK	O
and	O
CEPT	O
(	O
EU	O
)	O
27MHz	O
bands	O
only	O
.	O
</s>
<s>
Interference	O
problems	O
associated	O
with	O
badly	O
calibrated	O
amplitude	B-Device
modulated	I-Device
(	O
AM	B-Device
)	O
or	O
Single-Side-Band	B-Device
(	O
SSB	B-Device
)	O
equipment	O
were	O
cited	O
as	O
the	O
main	O
factor	O
,	O
and	O
it	O
was	O
made	O
clear	O
that	O
if	O
any	O
system	O
was	O
legalised	O
it	O
would	O
be	O
frequency	B-Application
modulated	I-Application
(	O
FM	B-Application
)	O
.	O
</s>
<s>
The	O
CB	O
lobby	O
argued	O
that	O
interference	O
from	O
AM	B-Device
was	O
unlikely	O
to	O
occur	O
from	O
the	O
use	O
of	O
original	O
unmodified	O
AM	B-Device
radio	O
equipment	O
,	O
a	O
view	O
initially	O
rejected	O
but	O
later	O
accepted	O
by	O
the	O
Ministry	O
of	O
Defence	O
.	O
</s>
<s>
Many	O
active	O
and	O
potential	O
users	O
continued	O
in	O
their	O
insistence	O
on	O
a	O
27MHz	O
system	O
,	O
although	O
for	O
a	O
locally	O
available	O
Citizen	B-Application
's	I-Application
Band	I-Application
system	O
,	O
the	O
27MHz	O
concept	O
was	O
not	O
universally	O
endorsed	O
.	O
</s>
<s>
The	O
government	O
initially	O
proposed	O
an	O
FM	B-Application
system	O
on	O
a	O
928MHz	O
band	O
with	O
an	O
RF	O
input	O
power	O
not	O
exceeding	O
500mW	O
.	O
</s>
<s>
The	O
CB	O
lobby	O
continued	O
to	O
insist	O
that	O
any	O
CB	O
system	O
had	O
to	O
use	O
the	O
27MHz	O
band	O
,	O
be	O
AM	B-Device
and	O
a	O
maximum	O
output	O
power	O
of	O
4watts	O
(	O
i.e.	O
</s>
<s>
These	O
awkward	O
frequencies	O
would	O
prevent	O
illegal	O
US	O
sets	O
from	O
being	O
modified	O
outside	O
of	O
the	O
type	O
approval	O
system	O
,	O
though	O
it	O
was	O
possible	O
to	O
have	O
existing	O
A.M.	O
radios	O
modified	O
to	O
comply	O
with	O
the	O
new	O
F.M.	B-Application
</s>
<s>
The	O
system	O
was	O
FM	B-Application
as	O
expected	O
,	O
but	O
one	O
initial	O
surprise	O
was	O
that	O
the	O
power	O
limit	O
was	O
set	O
at	O
4watts	O
.	O
</s>
<s>
Within	O
a	O
year	O
of	O
the	O
introduction	O
of	O
CB	O
to	O
the	O
UK	O
,	O
CB	B-Application
radio	I-Application
sets	O
were	O
being	O
given	O
away	O
free	O
with	O
some	O
purchase	O
or	O
other	O
by	O
many	O
of	O
the	O
major	O
retailers	O
.	O
</s>
<s>
It	O
is	O
not	O
permitted	O
to	O
add	O
the	O
CEPT	O
channels	O
to	O
existing	O
27/81	B-Algorithm
equipment	I-Algorithm
,	O
the	O
only	O
radios	O
permitted	O
to	O
operate	O
on	O
this	O
band	O
are	O
purpose-made	O
80-channel	O
or	O
CEPT-only	O
sets	O
.	O
</s>
<s>
The	O
National	O
Committee	O
for	O
the	O
Legalisation	O
Of	O
Citizens	B-Application
 '	I-Application
Band	I-Application
Radio	I-Application
was	O
a	O
pro	O
CB	O
lobby	O
consisting	O
of	O
interested	O
parties	O
and	O
(	O
at	O
one	O
point	O
)	O
up	O
to	O
60	O
members	O
of	O
Parliament	O
.	O
</s>
<s>
Some	O
REACT	O
units	O
provided	O
search	O
volunteers	O
to	O
assist	O
the	O
police	O
with	O
searching	O
for	O
missing	O
persons	O
(	O
something	O
that	O
still	O
occurs	O
today	O
with	O
ALSAR	O
and	O
RAYNET	O
albeit	O
without	O
CB	B-Application
radios	I-Application
)	O
.	O
</s>
<s>
Another	O
group	O
originally	O
formed	O
with	O
the	O
use	O
of	O
CB	B-Application
radio	I-Application
in	O
mind	O
are	O
REVCOM	O
,	O
though	O
this	O
group	O
no	O
longer	O
uses	O
the	O
CB	O
service	O
.	O
</s>
<s>
The	O
originally	O
imported	O
equipment	O
used	O
AM	B-Device
amplitude	B-Device
modulation	I-Device
and	O
SSB	B-Device
single-sideband	B-Device
modulation	I-Device
modes	O
of	O
transmission	O
.	O
</s>
<s>
The	O
UK	O
channels	O
that	O
were	O
legalised	O
on	O
2	O
November	O
1981	O
were	O
on	O
two	O
blocks	O
of	O
frequencies	O
:	O
40	O
channels	O
on	O
the	O
27MHz	O
band	O
and	O
20	O
channels	O
on	O
the	O
934MHz	O
band	O
,	O
both	O
of	O
which	O
used	O
FM	B-Application
(	O
frequency	B-Application
modulation	I-Application
)	O
and	O
both	O
unique	O
to	O
the	O
UK	O
.	O
</s>
<s>
Equipment	O
conforming	O
with	O
the	O
27	B-Algorithm
MHz	I-Algorithm
CB27/81	I-Algorithm
Bandplan	I-Algorithm
was	O
identified	O
as	O
"	O
CB27/81	O
"	O
.	O
</s>
<s>
In	O
1987	O
40	O
additional	O
frequencies	O
were	O
added	O
,	O
which	O
were	O
the	O
same	O
as	O
the	O
US	O
allocation	O
–	O
but	O
again	O
using	O
FM	B-Application
.	O
</s>
<s>
The	O
(	O
formerly	O
)	O
illegal	O
SSB	B-Device
mode	O
has	O
its	O
enthusiasts	O
and	O
adopted	O
a	O
different	O
style	O
of	O
call-sign	O
(	O
instead	O
of	O
a	O
'	O
handle	O
 '	O
)	O
in	O
the	O
manner	O
of	O
radio	O
amateurs	O
.	O
</s>
<s>
In	O
July	O
2015	O
,	O
ECC	O
Decision	O
(	O
15	O
)	O
05	O
doubled	O
the	O
number	O
of	O
analogue	O
channels	O
to	O
16	O
by	O
extending	O
analogue	O
operation	O
onto	O
the	O
446.1	O
–	O
446.2MHz	O
band	O
previously	O
used	O
by	O
digital	O
DMR/dPMR	O
equipment	O
,	O
effective	O
January	O
2016	O
;	O
from	O
January	O
2018	O
,	O
the	O
number	O
of	O
digital	O
channels	O
will	O
also	O
be	O
doubled	O
by	O
extending	O
onto	O
the	O
446.0	O
–	O
446.1MHz	O
band	O
used	O
by	O
analogue	O
FM	B-Application
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
increase	O
power	O
output	O
to	O
very	O
high	O
levels	O
using	O
power	O
amplifiers	O
,	O
and	O
in	O
some	O
cases	O
this	O
can	O
cause	O
interference	O
to	O
and	O
affect	O
the	O
operation	O
of	O
other	O
equipment	O
such	O
as	O
television	O
and	O
radio	O
,	O
and	O
also	O
to	O
other	O
CB	B-Application
radio	I-Application
users	O
.	O
</s>
<s>
From	O
the	O
inception	O
of	O
legalised	O
CB	B-Application
radio	I-Application
,	O
there	O
has	O
been	O
much	O
abuse	O
of	O
the	O
system	O
,	O
with	O
frequent	O
complaints	O
that	O
CB	B-Application
radio	I-Application
was	O
not	O
policed	O
properly	O
in	O
spite	O
of	O
the	O
licence	O
revenues	O
.	O
</s>
<s>
Many	O
of	O
the	O
original	O
advantages	O
of	O
mobile	O
CB	O
have	O
been	O
surpassed	O
by	O
the	O
development	O
of	O
mobile	B-Application
internet	I-Application
access	O
,	O
satellite	O
navigation	O
systems	O
,	O
and	O
the	O
proliferation	O
of	O
other	O
instant	O
communication	O
technologies	O
such	O
as	O
text	O
messaging	O
.	O
</s>
<s>
As	O
of	O
8	O
December	O
2006	O
,	O
CB	B-Application
Radio	I-Application
now	O
joins	O
PMR446	O
,	O
LPD433	B-Algorithm
and	O
SRD860	O
under	O
the	O
category	O
of	O
licence-free	O
personal	O
communications	O
.	O
</s>
<s>
In	O
June	O
2011	O
,	O
the	O
EU	O
announced	O
another	O
change	O
in	O
technical	O
specifications	O
for	O
CB	O
use	O
which	O
,	O
if	O
implemented	O
,	O
would	O
introduce	O
a	O
type	O
approval	O
for	O
both	O
AM	B-Device
and	O
SSB	B-Device
operation	O
.	O
</s>
<s>
This	O
would	O
permit	O
the	O
use	O
of	O
Single-Sideband	B-Device
and	O
AM	B-Device
operation	O
on	O
the	O
CEPT	O
CB	B-Application
radio	I-Application
band	O
,	O
and	O
Ofcom	O
proceeded	O
with	O
legislation	O
to	O
this	O
effect	O
on	O
27	O
June	O
2014	O
.	O
</s>
<s>
The	O
new	O
AM/SSB	O
legislation	O
permits	O
the	O
use	O
of	O
only	O
new	O
and	O
approved	O
sets	O
,	O
not	O
'	O
legacy	O
 '	O
multimode	O
sets	O
.	O
</s>
