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The data on #7 may not be accurate.
The P.R.F.
and pulse width may both be incorrect. This contact was too
strong to be rigorously examined. (We submerged for this
contact). The pulse could not be tuned off the r4eceiver
(neither frequency band), but did come to a definite peak at
140 mc/s.
The sky was heavily overcast. Just before making
the APR contact our radio receiver was blocked out, but it is
felt that this was coincidence (mentioned to suggest possibility
that contact was atmospheric; I do not feel that this was the
case, however).
Contacts #5 and #6 were probably the same radar
set, based somewhere near Camranh.
#5 was picked up about dawn just before diving.
Later this same morning we attacked and sank an 8,500 ton AK.
#6 was retained two hours while we were on a
northerly course. Three ship swings gave us bearings which
crossed near Camranh Bay. At the time of this contact there
was much other activity (See narrative).
The antenna was not fixed but no regular sweep
could be determined either the first or second time contact
was made. First contact was made 10 to 15 miles off
Camranh. Second contact was made 15 to 20 miles off Camranh
and lost at 25 to 30 miles.
The pulse was well formed, square with steep
sides.
There was not sufficient information to deter-
mine whether contact was lost due to excess range or due to
the set being turned off. Believe it was lost due to excess
range, since there were indications of weakening strength.
Contact #11 was possibly land based. Swung
ship once on this contact and got a bearing (fairly definite)
on Lombok. Made contact after passing through the strait 20
miles west and south of Lombok. Contact was lost at 40 miles.
The APR was manned continuously while going through Lombok
Strait and this radar was not picked up. The pip was on the
screen two minutes and off three minutes. During the two
minutes (plus) that it was on it was strong for 40-45 seconds,
weak 20-25 seconds. It went through this latter cycle
twice during the two minutes it was on. Probably antenna
rotated once every five minutes, and had four lobes in its'
field pattern. Rotation rate was carefully timed many times
and is considered accurate. The contact was weakening when it
was lost, but once again conclusive evidence is lacking that
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