<s>
Lobe	B-Algorithm
switching	I-Algorithm
is	O
a	O
method	O
used	O
on	O
early	O
radar	B-Application
sets	O
to	O
improve	O
tracking	O
accuracy	O
.	O
</s>
<s>
The	O
radar	B-Application
signal	O
switched	O
between	O
the	O
two	O
and	O
produced	O
two	O
"	O
blips	O
"	O
on	O
the	O
display	O
.	O
</s>
<s>
The	O
concept	O
was	O
used	O
only	O
briefly	O
,	O
and	O
was	O
almost	O
completely	O
replaced	O
by	O
conical	B-Algorithm
scanning	I-Algorithm
systems	O
by	O
the	O
end	O
of	O
World	O
War	O
II	O
.	O
</s>
<s>
The	O
concept	O
is	O
also	O
infrequently	O
referred	O
to	O
as	O
sequential	B-Algorithm
lobing	I-Algorithm
,	O
particularly	O
when	O
the	O
signal	O
steps	O
between	O
several	O
different	O
angles	O
rather	O
than	O
just	O
two	O
.	O
</s>
<s>
Early	O
radar	B-Application
antennas	O
generally	O
consisted	O
of	O
a	O
number	O
of	O
small	O
dipole	O
antennas	O
in	O
front	O
of	O
a	O
passive	O
reflector	O
.	O
</s>
<s>
In	O
early	O
use	O
the	O
system	O
was	O
instead	O
paired	O
with	O
a	O
searchlight	O
,	O
which	O
would	O
be	O
directed	O
onto	O
the	O
target	O
by	O
the	O
radar	B-Application
.	O
</s>
<s>
In	O
this	O
role	O
,	O
even	O
during	O
the	O
day	O
,	O
the	O
range	O
information	O
the	O
radar	B-Application
provided	O
was	O
still	O
invaluable	O
.	O
</s>
<s>
Lobe	B-Algorithm
switching	I-Algorithm
offered	O
greatly	O
improved	O
accuracy	O
for	O
the	O
addition	O
of	O
a	O
small	O
amount	O
of	O
complexity	O
.	O
</s>
<s>
Conical	B-Algorithm
scanning	I-Algorithm
was	O
similar	O
in	O
concept	O
to	O
lobe	B-Algorithm
switching	I-Algorithm
,	O
but	O
as	O
the	O
name	O
implies	O
it	O
was	O
operated	O
in	O
a	O
rotary	O
fashion	O
instead	O
of	O
two	O
directions	O
.	O
</s>
<s>
Conical	B-Algorithm
scanning	I-Algorithm
could	O
only	O
easily	O
be	O
used	O
on	O
an	O
antenna	O
with	O
a	O
single	O
feed	O
horn	O
,	O
which	O
is	O
only	O
practical	O
with	O
microwave	B-Application
radars	I-Application
.	O
</s>
<s>
As	O
such	O
systems	O
were	O
introduced	O
into	O
service	O
,	O
lobe	B-Algorithm
switching	I-Algorithm
generally	O
disappeared	O
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
jam	O
a	O
lobe	B-Algorithm
switching	I-Algorithm
radar	B-Application
with	O
relative	O
ease	O
if	O
one	O
knows	O
the	O
basic	O
operating	O
frequencies	O
of	O
the	O
radar	B-Application
.	O
</s>
<s>
In	O
the	O
case	O
of	O
a	O
lobe	B-Algorithm
switching	I-Algorithm
set	O
that	O
switches	O
lobes	O
30	O
times	O
a	O
second	O
,	O
a	O
jammer	O
can	O
be	O
constructed	O
to	O
send	O
out	O
a	O
weak	O
signal	O
on	O
the	O
same	O
frequency	O
that	O
also	O
varies	O
30	O
times	O
a	O
second	O
,	O
but	O
only	O
sends	O
out	O
a	O
signal	O
when	O
the	O
radar	B-Application
's	O
lobe	O
is	O
pointed	O
away	O
from	O
the	O
aircraft	O
which	O
is	O
easily	O
found	O
by	O
looking	O
for	O
a	O
low	O
point	O
in	O
the	O
received	O
signal	O
.	O
</s>
<s>
This	O
denies	O
the	O
radar	B-Application
angle	O
information	O
,	O
and	O
can	O
make	O
anything	O
but	O
gross	O
angle	O
tracking	O
difficult	O
.	O
</s>
<s>
One	O
way	O
to	O
avoid	O
this	O
problem	O
is	O
known	O
as	O
lobe	O
on	O
receive	O
only	O
(	O
LORO	O
)	O
,	O
which	O
uses	O
one	O
set	O
of	O
antenna	O
elements	O
to	O
send	O
a	O
non-lobe-switched	O
signal	O
,	O
and	O
two	O
additional	O
sets	O
for	O
lobe	B-Algorithm
switching	I-Algorithm
on	O
reception	O
.	O
</s>
<s>
Operation	O
is	O
basically	O
identical	O
to	O
a	O
normal	O
lobing	O
radar	B-Application
,	O
but	O
it	O
denies	O
any	O
information	O
about	O
the	O
lobing	O
to	O
the	O
target	O
aircraft	O
,	O
for	O
the	O
cost	O
of	O
some	O
additional	O
antenna	O
elements	O
(	O
or	O
more	O
commonly	O
,	O
a	O
second	O
antenna	O
)	O
.	O
</s>
<s>
Unsynchronized	O
"	O
blocks	O
"	O
of	O
signal	O
can	O
be	O
used	O
to	O
jam	O
LORO	O
radars	B-Application
,	O
although	O
it	O
is	O
not	O
as	O
effective	O
as	O
against	O
a	O
normal	O
lobing	O
system	O
and	O
generally	O
makes	O
the	O
operator	O
's	O
job	O
more	O
difficult	O
,	O
as	O
opposed	O
to	O
impossible	O
.	O
</s>
<s>
The	O
SCR-268	O
,	O
the	O
US	O
Army	O
's	O
first	O
radar	B-Application
system	I-Application
,	O
was	O
one	O
of	O
the	O
first	O
radar	B-Application
sets	O
to	O
use	O
lobe	B-Algorithm
switching	I-Algorithm
of	O
its	O
receiving	O
antennas	O
as	O
a	O
means	O
to	O
aim	O
anti-aircraft	O
searchlight	O
beams	O
at	O
aircraft	O
.	O
</s>
