<s>
Orange	B-Algorithm
Poodle	I-Algorithm
was	O
an	O
experimental	O
over-the-horizon	B-Architecture
radar	I-Architecture
developed	O
in	O
the	O
United	O
Kingdom	O
beginning	O
in	O
1949	O
and	O
tested	O
experimentally	O
in	O
1952	O
and	O
53	O
.	O
</s>
<s>
It	O
was	O
designed	O
to	O
detect	O
a	O
target	O
flying	O
at	O
an	O
altitude	O
of	O
at	O
a	O
range	O
of	O
,	O
well	O
below	O
the	O
radar	B-Algorithm
horizon	I-Algorithm
.	O
</s>
<s>
In	O
1948	O
,	O
Claude	O
Shannon	O
used	O
his	O
recently	O
introduced	O
science	O
of	O
information	O
theory	O
to	O
study	O
radar	B-Application
systems	I-Application
and	O
suggest	O
that	O
there	O
were	O
calculable	O
fundamental	O
limits	O
to	O
their	O
performance	O
.	O
</s>
<s>
This	O
was	O
unexpected	O
,	O
and	O
provoked	O
wide	O
interest	O
in	O
the	O
radar	B-Application
field	O
.	O
</s>
<s>
In	O
1949	O
,	O
the	O
Telecommunications	O
Research	O
Establishment	O
(	O
TRE	O
)	O
,	O
the	O
Air	O
Ministry	O
's	O
radar	B-Application
research	O
arm	O
,	O
began	O
applying	O
this	O
new	O
concept	O
to	O
consider	O
the	O
extraction	O
of	O
both	O
location	O
and	O
velocity	O
information	O
from	O
a	O
radar	B-Application
signal	O
,	O
and	O
to	O
the	O
expected	O
performance	O
of	O
long-range	O
radars	B-Application
against	O
low	O
flying	O
aircraft	O
and	O
the	O
detection	O
of	O
submarine	O
snorkels	O
in	O
rough	O
seas	O
.	O
</s>
<s>
The	O
work	O
was	O
interesting	O
enough	O
that	O
the	O
Ministry	O
of	O
Supply	O
funded	O
further	O
development	O
under	O
the	O
rainbow	O
code	O
Orange	B-Algorithm
Poodle	I-Algorithm
.	O
</s>
<s>
For	O
experimental	O
purposes	O
,	O
Marconi	B-Device
built	O
a	O
smaller	O
version	O
with	O
eight	O
elements	O
that	O
was	O
constructed	O
by	O
connecting	O
them	O
to	O
one	O
of	O
the	O
disused	O
Chain	O
Home	O
antennas	O
at	O
RAF	O
Downderry	O
in	O
Cornwall	O
.	O
</s>
<s>
The	O
tests	O
were	O
very	O
encouraging	O
and	O
led	O
to	O
plans	O
for	O
a	O
production	O
version	O
that	O
might	O
be	O
part	O
of	O
the	O
ROTOR	B-Application
network	O
.	O
</s>
<s>
However	O
,	O
by	O
the	O
end	O
of	O
the	O
year	O
development	O
had	O
been	O
cancelled	O
when	O
it	O
was	O
pointed	O
out	O
how	O
easily	O
the	O
system	O
was	O
interfered	O
with	O
by	O
local	O
shortwave	O
sources	O
;	O
an	O
enemy	O
could	O
easily	O
jam	O
the	O
radar	B-Application
using	O
low-cost	O
commercial	O
transmitters	O
while	O
still	O
well	O
below	O
the	O
horizon	O
.	O
</s>
