<s>
The	O
4-metre	O
(	O
70MHz	O
)	O
band	O
is	O
an	O
amateur	B-Algorithm
radio	I-Algorithm
band	I-Algorithm
within	O
the	O
lower	O
part	O
of	O
the	O
very	B-Algorithm
high	I-Algorithm
frequency	I-Algorithm
(	O
VHF	B-Algorithm
)	O
band	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
communication	O
on	O
the	O
4-metre	B-Algorithm
band	I-Algorithm
tends	O
to	O
focus	O
on	O
technical	O
topics	O
,	O
with	O
long	O
'	O
rag	O
chews	O
 '	O
being	O
the	O
norm	O
as	O
long	O
as	O
there	O
is	O
some	O
local	O
activity	O
.	O
</s>
<s>
In	O
1956	O
,	O
after	O
several	O
years	O
of	O
intense	O
lobbying	O
by	O
the	O
Radio	O
Society	O
of	O
Great	O
Britain	O
(	O
RSGB	O
)	O
,	O
the	O
4-metre	B-Algorithm
band	I-Algorithm
was	O
allocated	O
to	O
British	O
community	O
radio	O
stations	O
as	O
a	O
replacement	O
for	O
the	O
old	O
5-metre	O
band	O
allocation	O
.	O
</s>
<s>
For	O
several	O
years	O
the	O
4-metre	B-Algorithm
band	I-Algorithm
allocation	O
was	O
only	O
200kHz	O
wide	O
,	O
from	O
70.2	O
to	O
70.4MHz	O
;	O
it	O
was	O
later	O
extended	O
to	O
70.025	O
–	O
70.7MHz	O
.	O
</s>
<s>
Regarding	O
the	O
Amateur	O
Radio	O
Service	O
the	O
DSI	O
management	O
team	O
recommended	O
(	O
among	O
other	O
things	O
)	O
that	O
70MHz	O
be	O
considered	O
as	O
an	O
amateur	B-Algorithm
band	I-Algorithm
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
traditional	O
users	O
(	O
United	O
Kingdom	O
,	O
Gibraltar	O
and	O
the	O
British	O
Military	O
Bases	O
in	O
Cyprus	O
)	O
,	O
an	O
increasing	O
number	O
of	O
countries	O
in	O
Europe	O
and	O
Africa	O
have	O
authorised	O
the	O
use	O
of	O
the	O
4-metre	B-Algorithm
band	I-Algorithm
to	O
community	O
radio	O
stations	O
.	O
</s>
<s>
Movement	O
away	O
from	O
the	O
old	O
Eastern	O
European	O
VHF	B-Algorithm
FM	B-Application
broadcast	O
band	O
and	O
migration	O
of	O
commercial	O
stations	O
to	O
higher	O
frequencies	O
in	O
recent	O
times	O
allowed	O
a	O
slow	O
but	O
constant	O
growth	O
in	O
the	O
number	O
of	O
countries	O
where	O
4-metre	O
amateur	O
radio	O
operation	O
is	O
permitted	O
.	O
</s>
<s>
The	O
4-metre	B-Algorithm
band	I-Algorithm
shares	O
many	O
characteristics	O
with	O
the	O
adjacent	O
6-metre	B-Algorithm
band	O
.	O
</s>
<s>
As	O
the	O
band	O
is	O
higher	O
in	O
frequency	O
,	O
it	O
does	O
not	O
display	O
the	O
same	O
propagation	O
mechanisms	O
via	O
the	O
F2	O
ionospheric	O
layer	O
normally	O
seen	O
at	O
HF	B-Algorithm
which	O
occasionally	O
appear	O
in	O
6metres	O
,	O
leastwise	O
not	O
at	O
temperate	O
latitudes	O
.	O
</s>
<s>
However	O
,	O
sporadic	O
E	O
is	O
common	O
on	O
the	O
band	O
during	O
the	O
summer	O
season	O
and	O
tropospheric	O
propagation	O
is	O
marginally	O
more	O
successful	O
than	O
on	O
the	O
6-metre	B-Algorithm
band	O
,	O
with	O
propagation	O
via	O
the	O
Aurora	O
Borealis	O
and	O
meteor	B-Language
scatter	O
generally	O
highly	O
effective	O
.	O
</s>
<s>
While	O
sporadic	O
E	O
permits	O
Europe	O
wide	O
communication	O
,	O
the	O
band	O
is	O
still	O
used	O
for	O
wide	O
bandwidth	B-Algorithm
,	O
high	O
power	O
FM	B-Application
broadcasting	O
on	O
the	O
OIRT	O
FM	B-Application
band	O
in	O
a	O
declining	O
number	O
of	O
Eastern	O
European	O
countries	O
.	O
</s>
<s>
Access	O
to	O
the	O
4-metre	B-Algorithm
band	I-Algorithm
remains	O
challenging	O
due	O
to	O
limited	O
availability	O
of	O
commercial	O
4-metre	O
transceivers	O
and	O
radio	O
equipment	O
in	O
general	O
.	O
</s>
<s>
Some	O
low	O
power	O
FM	B-Application
commercial	O
equipment	O
is	O
available	O
,	O
however	O
these	O
units	O
are	O
of	O
relatively	O
simple	O
specifications	O
and	O
generally	O
suitable	O
for	O
communication	O
of	O
up	O
to	O
around	O
or	O
so	O
with	O
simple	O
antennas	O
.	O
</s>
<s>
Currently	O
,	O
the	O
only	O
Japanese-made	O
,	O
"	O
mass-market	O
"	O
amateur	O
radio	O
transceivers	O
to	O
cover	O
the	O
4-metre	B-Algorithm
band	I-Algorithm
as	O
standard	O
are	O
the	O
KenwoodTS	O
890	O
,	O
ICOM	O
IC-7100	O
and	O
IC-7300	O
(	O
UK	O
models	O
)	O
,	O
previously	O
there	O
was	O
the	O
UK	O
specification	O
Yaesu	O
FT-847	O
with	O
4m	O
which	O
was	O
discontinued	O
in	O
2005	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
many	O
4-metre	O
users	O
gain	O
access	O
to	O
the	O
band	O
by	O
using	O
converted	O
"	O
Low	O
band	O
"	O
VHF	B-Algorithm
ex-PMR	O
(	O
private	O
mobile	O
radio	O
)	O
transceivers	O
but	O
invariably	O
these	O
only	O
have	O
either	O
AM	B-Device
or	O
FM	B-Application
and	O
those	O
users	O
who	O
prefer	O
to	O
have	O
a	O
multi-mode	O
capability	O
but	O
ca	O
n't	O
afford	O
a	O
secondhand	O
YaesuFT-847	O
,	O
normally	O
use	O
transverters	O
,	O
either	O
purposely	O
built	O
home	O
builds	O
or	O
sometimes	O
even	O
converted	O
6-metre	B-Algorithm
or	O
2-metre	O
versions	O
.	O
</s>
<s>
Circa	O
2014	O
a	O
mono-band	O
multi-mode	O
70MHz	O
SSB	B-Device
/	O
CW	O
transceiver	O
was	O
released	O
by	O
Noble	O
Radio	O
.	O
</s>
<s>
Most	O
modern	O
radios	O
support	O
the	O
4-meter	B-Algorithm
band	I-Algorithm
(	O
software-defined	B-Architecture
radios	I-Architecture
–	O
SDRs	O
and	O
others	O
)	O
.	O
</s>
<s>
In	O
the	O
UK	O
the	O
band	O
has	O
a	O
mix	O
of	O
AM	B-Device
,	O
FM	B-Application
and	O
DX	O
activity	O
,	O
assisted	O
by	O
the	O
recent	O
support	O
for	O
70MHz	O
in	O
newer	O
amateur	O
radio	O
equipment	O
.	O
</s>
<s>
There	O
is	O
considerable	O
AM	B-Device
activity	O
in	O
the	O
Dublin	O
area	O
.	O
</s>
<s>
As	O
band	O
occupancy	O
is	O
relatively	O
low	O
,	O
FM	B-Application
operation	O
tends	O
to	O
take	O
place	O
on	O
the	O
70.450MHz	O
calling	O
frequency	O
,	O
and	O
AM	B-Device
operation	O
on	O
the	O
70.260MHz	O
calling	O
frequency	O
.	O
</s>
<s>
Cross-band	O
working	O
between	O
the	O
6-metre	B-Algorithm
band	O
or	O
the	O
10-metre	O
band	O
is	O
common	O
to	O
make	O
contacts	O
countries	O
where	O
the	O
band	O
is	O
not	O
allocated	O
.	O
</s>
<s>
DX	O
voice	O
traffic	O
in	O
SSB	B-Device
mode	O
can	O
be	O
found	O
around	O
the	O
SSB	B-Device
calling	O
frequency	O
of	O
70.200MHz	O
,	O
whereas	O
AM/FM	O
contacts	O
tend	O
can	O
be	O
initiated	O
at	O
the	O
70.260MHz	O
AM/FM	O
centre	O
of	O
activity	O
.	O
</s>
<s>
polarisation	O
,	O
12kHz	O
maximum	O
bandwidth	B-Algorithm
,	O
no	O
portable	O
operation	O
,	O
non	O
interference	O
basis	O
,	O
all	O
transmissions	O
to	O
be	O
logged	O
with	O
frequency	O
,	O
antenna	O
direction	O
,	O
date/time	O
,	O
call	O
signs	O
)	O
for	O
four	O
months	O
,	O
Starting	O
May2	O
and	O
ending	O
at	O
the	O
end	O
of	O
August	O
each	O
year	O
(	O
effectively	O
for	O
the	O
sporadic-E	O
season	O
)	O
.	O
</s>
<s>
United	O
States	O
has	O
one	O
experimental	O
transmitter	O
,	O
station	O
WE9XFT	O
in	O
Virginia	B-Application
,	O
transmitting	O
CW	O
on	O
70.005MHz	O
.	O
</s>
