Evening star., 1945-08-15

It's path, II Is renected back to a re-
ceiver and the pulse (or "pip')
registers as light on cathode ray
screen. Since the pulse" travels
with the speed of 10000 miles a
second or 1923 yards each millionth
of second, the distance is deter
minable accurately. while the known
direction of the beam registers its
location >or bearing.
The most widely used method of
radar presentation is plan position
indicator which shows the area
scanned by radar on a round disc
in manner similar to a relief map.
The "pips" show water as dark
areas: land is light: ships, planes
and cities appear as bright areas.
Radar is limited in use by the
height at which the pulses are trans
mitted and received. Surface radar
can scan sea or land up to a dis
tance where the pulses" shoot OF
beyond the curvature of the earth
A high-altitude bomber can, there
fore, scan a tremendously increased
area.
Thus, when the Germans began
sinking Allied shipping at the rate
of $4,000 tons a day in 1912, the
Allies were prepared with airborne
radar perfected by the British for
mounting on search planes. Since
submarines must surface for air and
to recharge batteries, the common
practice was to emerge at night
when low visibility gave protection
Planes began destroying U-Boats in
increasing numbers, or guiding sur
face vessels to the area for demoli-
ton of the subs by gunfire and
depth charges. Slow and anti
quated B-18s were first used in this
country with a base at Langley Field
Later the sea search included severa
hundred planes in the United States
operating under the 1st AAF Anti.
submarine Command.
Warned of Foe.
The Germans counteracted by de.
veloping receiver for the radal
pulses emitted by the planes, ano
forewarned, were able to submerge
in time to escape the bomber. Radal
does not register beneath the sur.
face of the sea, and the Nazis
operated with increased boldnes:
until the United States developed {
microwave pulse" which the SUD.
marine commanders could not de.
tect. Despite desperate attempts tt
fathom the secret of the Allied sue.
, cess which during May, June ans
July, 1943, caused nearly 100 kills,
the Germans were unsuccessful. II
the last days of the war, U-boat!
were using a "schnorkel," an elastic
tube which permitted submarines tt
remain submerged while drawing
fresh air from the surface.
/ BY establishing radar warnini
networks before the war, the Brit
ish people were able to Civ
ample warning to the small RAJ
/ during the Battle for Britain
thereby conserving pilots. plane
and fuel. Without the warning de
vice the pilots would have beel
compelled to maintain constant pa
trolls over the island, never certain
where the Nazi bombers woul.
strike. Night fighters were equipped
with radar to find and destroy tn
fleets which Marshal Goerinl
switched over to night attacks OF
England after his disastrous day
time bombing attempts. The nigh
attacks were equally disastrous *
the Germans.
BY the time the vi buzz bomb!
were being shot at England ant
Antwerp, American surface radal
had been developed to the poin
where 1t could track the v boml
from the moment 1t left launchin,
sites. American antiaircraft artil
lery, aiding the British, shot dow
the bombs in vast numbers, tn,
guns pointed, tracking and firin,
automatically when the closely in
tegrated radar and computers fixes
the target. The British late
| adopted this type Of equipment