Radar System Engineering

202 THE GATHERING AND PRESENTATION OF RADAR DATA [SEC.6.13
9. l-cm wavelength used gives a beamwidth of 10°, which is sharp enough
to allow a target on the same level as that of the AI-equipped aircraft to
be followed out to several times the altitude common to the two aircraft
without undue difficulty from ground return.
Two types of indicator are provided. The radar operator has a
B-scope which shows targets on a range-azimuth display; this is provided
with a movable marker that enables the operator to feed to the other
indicator—a C-scope showing azimuth and elet-ation—only the video
signals in a range interval centered on the range at Ivhich the marker is
receiving
ntenna
ing
Beam patterns
(Top view)
ansmitted
beam
t receiving
ntenna
Beam patterns
(Sdewew)
ted
lng
Ground return
Target echo:
left antenna
Alhtude
&
Target ech
right anten
Range to
target
antenna
Azimuth indicator
Elevatlon indicator
FIG. 633.-Bean, patterns and ind,cat,on of Br,tl.h .11lfark I\- (SCR-540).
set. The unfavorable signal-to-noise characteristics of the C-scope are
thus sonmvhat mitigated, and the C-scope, ~vhich is repeated for the
benefit of the pilot, displays only the dr>ired target. .~ range meter
operated by the position of the radar operator’< mo~-able marlier is also
pro~-ided to enable the pilot to gauge the progress of the interception.
.\.\F.
The SCR-720 has been used with success lmth by the R.IF and the
.\n airborne automatic tracking radar-essentially a light version of
the S~R-584 described in the next section—~vas designed for .11 use and
manufactured in small quantity Though it \\-as operationally very
satisfactory and \\-ashighly regarded by night fighter pilots Ivho fle\\-}rith
it, it \vas never used in the ~~-ar,principally }~erause of the lo~~ priority
put by the .\.\F on night air defense after 1!)42 This set was t~csignatecf
SCR-?02, .\\’ .\PG-l, and (made by another manll~acturer) .1S .lPG-2.
The difficult problem of providing .11 equipment for single-engine.
single-seat, carrier-based X“avy nightfighters was solvecl in a marginally
n