<s>
The	O
WSR-1	O
or	O
Weather	O
Surveillance	O
Radar-1	O
was	O
one	O
of	O
the	O
first	O
weather	B-Application
radars	I-Application
and	O
the	O
first	O
used	O
by	O
a	O
civilian	O
organization	O
in	O
the	O
US	O
.	O
</s>
<s>
The	O
WSR-1A	O
,	O
WSR-3	B-Algorithm
,	O
and	O
WSR-4	O
were	O
also	O
variants	O
of	O
this	O
radar	O
.	O
</s>
<s>
The	O
first	O
WSR-1	O
in	O
the	O
USA	O
was	O
at	O
Washington	O
National	O
Airport	O
in	O
Washington	O
,	O
D.C.	O
in	O
1947	O
,	O
and	O
the	O
last	O
WSR-3	B-Algorithm
was	O
retired	O
by	O
1978	O
.	O
</s>
<s>
The	O
modifications	O
were	O
conducted	O
by	O
the	O
weather	O
service	O
and	O
the	O
modified	O
radars	O
took	O
the	O
successive	O
names	O
of	O
WSR-1	O
,	O
WSR-1A	O
,	O
WSR-3	B-Algorithm
and	O
WSR-4	O
,	O
depending	O
on	O
the	O
gradual	O
improvement	O
of	O
hardware	O
.	O
</s>
<s>
Major	O
cities	O
in	O
Texas	O
have	O
been	O
asked	O
to	O
fund	O
the	O
operation	O
(	O
both	O
the	O
private	O
and	O
public	O
sectors	O
)	O
of	O
modifying	O
and	O
implementing	O
the	O
WSR-1	O
,	O
WSR-1A	O
,	O
WSR-3	B-Algorithm
and	O
WSR-4	O
.	O
</s>
<s>
After	O
1956	O
the	O
modification	O
of	O
the	O
APS-2F	O
radars	O
in	O
their	O
WSR-1	O
,	O
WSR-1A	O
,	O
WSR-3	B-Algorithm
and	O
WSR-4	O
versions	O
was	O
assigned	O
to	O
the	O
Weather	O
Office	O
headquarters	O
which	O
had	O
to	O
move	O
some	O
antennas	O
that	O
had	O
originally	O
been	O
installed	O
to	O
locations	O
where	O
it	O
was	O
difficult	O
to	O
ensure	O
the	O
maintenance	O
.	O
</s>
<s>
In	O
April	O
1975	O
,	O
at	O
the	O
peak	O
of	O
the	O
program	O
,	O
82	O
WSR-1	O
,	O
WSR-1A	O
,	O
WSR-3	B-Algorithm
and	O
WSR-4	O
were	O
in	O
service	O
.	O
</s>
<s>
Some	O
were	O
replaced	O
by	O
WSR-57s	O
,	O
but	O
most	O
remained	O
in	O
service	O
until	O
they	O
were	O
replaced	O
by	O
WSR-74s	B-Algorithm
during	O
a	O
period	O
from	O
1976	O
to	O
1980	O
.	O
</s>
<s>
The	O
WSR-1	O
to	O
4	O
series	O
,	O
the	O
first	O
operational	O
weather	B-Application
radar	I-Application
in	O
the	O
United	O
States	O
,	O
used	O
the	O
AN/APS	O
-2F	O
electronics	O
,	O
including	O
a	O
superheterodyne	O
receiver	O
,	O
but	O
with	O
a	O
larger	O
antenna	O
.	O
</s>
<s>
As	O
time	O
progressed	O
and	O
experience	O
with	O
the	O
original	O
design	O
increased	O
,	O
the	O
Weather	O
Bureau	O
felt	O
confident	O
enough	O
to	O
upgrade	O
the	O
WSR-1	O
to	O
WSR-1A	O
,	O
eventually	O
finalizing	O
on	O
the	O
WSR-3	B-Algorithm
and	O
WSR-4	O
model	O
.	O
</s>
<s>
This	O
frequency	O
is	O
in	O
the	B-Algorithm
S	I-Algorithm
band	I-Algorithm
which	O
is	O
still	O
used	O
by	O
the	O
current	O
US	B-Algorithm
weather	I-Algorithm
radar	I-Algorithm
network	I-Algorithm
.	O
</s>
<s>
The	O
WSR-1	O
used	O
a	O
panoramic	O
display	O
(	O
PPI	B-Algorithm
)	O
placing	O
weather	O
echoes	O
in	O
azimuth/distance	O
coordinates	O
on	O
a	O
circular	O
screen	O
whose	O
center	O
represented	O
the	O
position	O
of	O
the	O
radar	O
,	O
and	O
also	O
a	O
linear	O
oscilloscope	O
(	O
A-Scope	O
)	O
showing	O
the	O
intensity	O
of	O
the	O
echoes	O
according	O
to	O
their	O
distance	O
from	O
the	O
radar	O
.	O
</s>
<s>
The	O
WSR-3	B-Algorithm
and	O
WSR-4	O
used	O
A-Scope	O
displays	O
and	O
height/distance	O
displays	O
(	O
RHI	O
)	O
which	O
allows	O
a	O
vertical	O
sectional	O
view	O
in	O
a	O
chosen	O
direction	O
.	O
</s>
<s>
From	O
a	O
technical	O
point	O
of	O
view	O
,	O
the	O
WSR-4	O
had	O
a	O
traveling-wave	O
tube	O
that	O
improved	O
the	O
sensitivity	O
compared	O
to	O
the	O
WSR-3	B-Algorithm
.	O
</s>
<s>
Burrwood	O
,	O
LA	O
1956	O
1960	O
WSR-4	O
Fort	O
Worth	O
,	O
TX	O
April	O
21	O
,	O
1954	O
April	O
1961	O
WSR-57	O
Hartford	O
,	O
CT	O
1955	O
1959	O
WSR-3	B-Algorithm
Dodge	O
City	O
,	O
KS	O
June	O
13	O
,	O
1954	O
July	O
25	O
,	O
1963	O
WSR-3	B-Algorithm
Lubbock	O
,	O
TX	O
1954	O
August	O
1972	O
WSR-74C	O
Norfolk	O
,	O
NE	O
July	O
27	O
,	O
1947	O
1976	O
WSR-74C	O
North	O
Omaha	O
,	O
NE	O
1955	O
1977	O
WSR-74C	O
Oklahoma	O
City	O
,	O
OK	O
March	O
1	O
,	O
1955	O
1960	O
WSR-57	O
Philadelphia	O
,	O
PA	O
November	O
20	O
,	O
1959	O
?	O
</s>
<s>
Tampa	O
,	O
FL	O
1956	O
1960	O
WSR-57	O
Topeka	O
,	O
KS	O
1953	O
1957	O
WSR-3	B-Algorithm
Tulsa	O
,	O
OK	O
May	O
4	O
,	O
1956	O
1976	O
WSR-74C	O
Waco	O
,	O
TX	O
April	O
28	O
,	O
1955	O
1976	O
WSR-74C	O
Washington	O
,	O
DC	O
March	O
12	O
,	O
1947	O
?	O
</s>
