If you can see this text here you should update to a newer web browser
Normal | Highlight & Comment Highlighted Text will be in Yellow.
|Note: This is part of a large report I came across in the archives. The entire report was more than I had time to scan at the time, but I grabbed this section out of interest.|
1. Combat Infomation Center.
SK RADAR: The SK continued to be the primary air search radar for this ship. The receiver had a tendency to be blocked by what appeared to be a CW (continuous wave) signal, however, the receiver going into oscillations might give the same indications. All tubes were replaced in the receiver and PPI (plan position indicator) video section and a spare receiver did not alleviate this intermittent trouble. The indications never persisted for a sufficient length of time to permit the trouble to be isolated. It could always be eliminated by using the A-J controls, at some cost in efficiency, however. Field change 02 was made with no effect. The 12BP7 PPI was replaced due to trouble with a poor heater, which appeared intermittently as a disappearance of the PPI trace. Small and very high targets, (over 20,000') seemed to have a shorter range of detection than one would normally expect. Several times small enemy aircraft (i.e. Zekes, Nicks, Tonys, etc) which subsequently were shown to have been above 20,000' got into 30-35 miles before being detected. The detection range made it appear as though the target was very low, and the target indications were very weak when first detected.
SC-3 RADAR: The SC-3 performance improved considerably, especially in the latter part of this operation although it did seem to be somewhat unstable in tuning. The equipment is kept continuously operating whether or not it is manned and it is believed that this improves operation considerably. It is estimated that on the unobstructed bearings the reliable range of a division of CAP which is not in a fade area is approximately 60 miles. A few times the SC-3 could continue tracking a target that had faded for the SK.
The replacement of the SC-3 by an SK-2 is highly recommended for better protection to the ship and task group. It is believed that this will improve present radar information in three ways: (l) improved maximum ranges on unobstructed bearings (000 degrees to 270 degrees relative) (2) improved IFF (Identification Friend or Foe) performance (3) improved resolution of attacks developing within 20-30 miles of the disposition. During continued intensive operations, it is found necessary to secure the SK radar for 2-3 hours each 10 days on the average in order to maintain proper operating efficency. When this is done within 60-70 miles of enemy territory, there is a definite feeling of insecurity until the SK is back in commission. The SC-3 does not provide reliable protection at SK ranges.
SM RADAR: For this operation the SM operated well and fairly trouble free. Several times phantom targets appeared in the vicinity of the NANSEI SHOTOS (See Enclosure (A)). The antenna control system developed no trouble except in the train amplifier of the stable element. The high voltage filter condenser failed in the rectifier unit of the amplifier. The RF sensitivity dropped down for several days due to a poor TR tube (721A). This poor tube was installed as a matter of routine maintenance to replace a tube used 500 hours. The AGC (Automatic Gain Control) circuit of the receiver operated the short gate channel at too low a gain several time, due to the high level of interference. Little can be done except to cut the AGC out. The flexible coupling of the wobbler motor slipped on the drive motor shaft due to the loss of the key. Another key was used with an Allen screw to secure it in place more positively.
Height readings seemed inconsistent in that the error was either high or low; however for most operations, heights were accurate enough. Many times the SM picked up targets undetected by the SK radar, which were at altitudes between 3,000' and 6,000' at ranges of 50-70 miles.
The IFF leaves very much to be desired. IFF indications and target indications on the SM can only be correlated on the basis of range due to the bearing ambiguity of the omnidirectional BM "stovepipe". The target and IFF can be assumed to be from the same source if they track together but even this is not reliable and often the tactical situation is such that the time for tracking cannot be spared. The single, small bandit mixed with many friendlies at 20-30 miles is proving increasingly dangerous as recent actions and damaged carriers have indicated, including the HANCOCK. The inherent resolution of the SM radar is such as to resolve such a single plane in a group of friendlies, BUT THE IDENTIFICATION GEAR IS NOT CAPABLE OF SO DOING. It is therefore, recommended that an SM "A" band directional array be developed with the highest priority. It may save a carrier! We have directional "G" band interrogation which has proved to be of no practicl value on this or any other CV so far as is known and it would seem that a modification could be readily developed for installation by operating carriers of directional "A" band interrogation. At present the value of the SM radar is measurably reduced by this deficiency. THERE IS LITTLE COMFORT IN EARLY TARGET DETECTION WITHOUT EARLY TARGET IDENTIFICATION.
IFF The IFF situation is still far from satisfactory. A great deal of interference is present due to five VHF channels, MAN equipment, TBS, and YE-1 and planes warming up on the flight deck. Most of these can be eliminated by careful selection of operating frequencies but it is almost impossible all interference from any one interrogator.
The 2C26's in the BM interrogator fail quite frequently; in most cases being gassy from a cracked envelope. Some trouble was encountered with the 15E's and 2X2's. In the BL-6's T102 has a tendency to overheat when the 2x2 starts to fail or other components fail.
The screen grid resistor of the 807 tube and the parasitic suppressor resistor of the 15E's also burned out. The BL's on the whole are much more reliable than the single BM that we have, and slight maladjustments appear to effect the sensitivity much less. This may be due in large measure to the non-directional characteristics of the BM antenna, however.
The omni-directional array of the BM is very unsatisfactory and always causes doubt as to the reliability of a friendly contact reported by the SM radar. (See SM report).
YJ-1 RADAR BEACON The operation of the YJ-1 was completly unsatisfactory during the whole operation despite a check by a Hazeltime engineer prior to getting underway and despite ???? (there was a whole like of text that was completely unreadable here) the constant effort of ship's force. The receiver tends to squitter (squitter is a random pulse used in some navigating beacons) at much too high a rate and is erratic. The anti-squitter controls seem to stop the squitter and make the receiver insensitive at the same time. The receiver circuits appear to be normal from a voltage and resistance check. A modified antenna was installed performance was still effectively nil. It is hoped that a new receiver may clear up the trouble but it is recommended that a YJ-2(b) be instailed at the earliest opportunity for reliable operation of this type of equipment.
SG-1 and PPI's This gear functioned normally and with little trouble during this period. It is reiterated that the use of the SG radar for station keeping precludes it's effective use for search, the purpose for which it is intended. A more efficient sea-return suppressor may improve this condition but early installation of a second surface search system is desirable in any case.
MARK 12 and MARK 22 FIRE CONTROL RADARS These radars continued to operate well and as usual were extremely valuable during night air attack. The equipment during some day attacks enabled Main Battery Plot to have a solution set up before the target closed sufficiently to enable it to be tracked effectively by optics. In all cases it enable the pointer and trainer to set on the target promptly at maximum optical range.
It is believed that "A" band interrogators could be extremely useful with this equipment. They would be especially valuable during the night melee which sometimes occurs with VF(N) over or near the formation at the same time as enemy aircraft. This does happen and not infrequently, the best efforts of night intercept Officers and Group FDO's, notwithstanding.
(1) ENEMY RCM: During this operation it became increasingly evident that Japanese night flying aircraft have some means of knowing when our VF(N) are attempting to intercept them, possibly due to our use of IFF. Violent evasive manuevers, changes in altitude and heading and dropping of quantities of what appeared to be 200 mc window ("Window" was a WWII code name for radar-deceptive chaff that was dropped from aircraft) resulted and the problems of the night intercept officer were increased.
At ranges of 60 and 70 miles the window seemed particularly effective since the SK/SC had difficulty in distinguishing between the bogey being intercepted and the window, especially when the bogey was being tracked at maximum range. Another night when a Betty was splashed about 20 miles East of the group of ESSEX VF(N) controlled by the HANCOCK, a second "Bogey" appeared immedintely after the disappearance of the first and in proximity to the place where it was shot down. This same phenomanon was noted on another occasion off Formosa in early October when a single Emily was shot down by INDEPENDENCE VF(N) and second "Bogey" appeared almost in the space recently vacated by the Emily. In both cases it is suggested that the window only became visible to the radar after being dispersed for a few seconds after the sewing plane was splashed, or also the force of the explosion spread the window which was still contained in the plane.
On one occassion off Okinawa a single bogey flew a roughly circular course about the force as a center at a radius of about 60-70 miles. He was tracked for approximately 175 mi., and this radius may indicate the effective range of the radar in use since a strong radar signal was received at this time. This is in notable comparison to past performances where enemy aircraft have flown within 4-5 miles of a picket and 25-30 miles of the force apparently without detecting the presence of the disposition. This was noted off both Luzon and the Empire
Own RCM No new enemy frequencies were noted and they are therefore not noted herein. On 5 April 1945 this vessel jammed on 155 mc, from 0510 until 0525. Zone (-9) on order of CTU 58.3.2
BATTLE DAMAGE Battle damage was negligible on all search radars and they continued to operate normally except for the BM Interrogator overload relay which tripped out and was immediately reset. The after Mark 22 had a 10O0 volt keep-alive cable severed by shrapnel but it was immediately and easily repaired. The forward Mark 12 antenna was badly damaged by shrapnel and is beyond repair by ship's force. The forward Mark 22 cables were severed by shrapnel but antenna itself was undamaged. (see photographs) (not included) On the whole it is considered that the radars performed very well under severe shock conditions and such performance ia a credit to the design agencies.
b. Fighter Direction. The U.S.S. HANCOCK begen this operation as part of Task Group 58.2 with the Group Fighter Director embarked upon the U.S.S. FRANKLIN. From early morning of 18 March until late that afternoon about sixteen bandits were splashed by the Force. These were Bettys, Frances, Zekes and Judys, and while most of them were splashed by the CAP about three or four were shot down by AA from the CV's and one Kamakaze (SIC) missed in his dive and hit the water. These bandits came in singly or in pairs and invariably when in pairs would split up at the limit of visibility. Altitudes varied with the majority at angels five to ten or mattress and a few at angels one. It was also noted that the fast Bettys and Frances either came in popeye or mattress with an occasional one at angels twenty.
Each Group Fighter Director designated the controlling ship in his Group for each raid and generally put a backing up division between base and the intercepting division. This has been found necessary even against a single bogey being intercepted by another Task Group.
The morning of 19 March a questionable bogey was picked up at 240° about forty-five miles, time 0650, closing, and in checking some bases believed it showed friendly. There were many friendlies to the West and another Task Group was at 300° fifteen miles. Planes were turning up on all decks for a 0700 strike launch, and the usual interference caused by planes turning up gave some doubt as to this bogey's identity. However, within a minute the Task Group Fighter Director told the SAN JACINTO to start out a division to investigate. About three minutes later this vessel was told to send out a division to back up the other division. When the bogey was at 250° fifteen miles this vessel's SM picked out the bogey from at least fifty friendly groups of planes in the close vicinity. The Task Group to the Northwest was apparently intercepting also. A minute later, or about 0700, a Tally-ho was made by the SAN JACINTO division which was amplified as being a division of friendly fighters. The HANC0CK division was then two miles from the bogey but by the time they could see him he was at 345° eight miles and starting to dive. Our lookouts also saw him then and with the fire control radars on target, this vessel commenced firing just before he pushed over in a dive and hit the FRANKLIN with a bomb released at low altitude.
Interference to the radar scopes caused by planes turning up on deck is a serious problem since it often makes questionable the identity of even the majority of airborne planes. Also the Tally-Ho of the friendlies caused a slight delay to check positions, before deciding they had the wrong bogey. However, these interceptions were not completed in time due partially to the very limited visibility in the scattered clouds and haze that the bandit used until ready to push over in his dive.
Task Group Fighter Direction was immediately assumed by this vessel. At 0740 a SAN JACINTO division controlled by that vessel splashed a Judy at 290° twenty miles. That morning at 1025 the U.S.S. ENTERPRISE, with CTG 58.5 embarked, joined Task Group 58.2 and assumed tactical command. During the morning CTG 58.2, with
only a partial staff, and ComCarDiv 4, transferred to this vessel from the FRANKLIN. TG 58.2 was directed to act independently of TF 58 with a primary mission of protecting the U.S.S. FRANKLIN during retirement from the area. At the request of CTG 58.5's Fighter Director, Group fighter direction was retained by the HANCOCK until about 1300 so that they could make the necessary frequency changes. CTG 58.5 then took TGFD (Task Group Fighter Director) until the first launch on 20 March. At that time TGFD was returned to CTG 58.2, using this vessel's CIC team, for daytime operations with the instructions that CTG 58.5 would assume TGFD for night operations. However, it was decided that since CTG 58.5 was acting as OTC the ENTERPRISE should take over TGFD for better coordination, and again TGFD duties were returned to CTG 58.5 at 0800.
Air attacks were prevalent during the day and sixteen enemy aircraft were shot down by ships' gunfire. At this time there is no accurate information as to the number shot down by the CAP'S.
After the U.S.S. ENTERPRISE was hit, at 1628 the afternoon of 20 March, CTG 58.2 assumed OTC duties and the U.S.S. HANCOCK again operated as TGFD.
The CAP finally splashed the Judy at 300º sixteen miles, that had bombed the ENTERPRISE. At 1642 another enemy plane barely missed the ENTERPRISE with a bomb and at 165O yet another bomb missed this vesel by 30 yards, this latter plane was then splashed by AA fire of the HANCOCK. Attacks continued and after darkness many enemy planes continued to track the Force. Difficulty was experienced because some of the Night CAP were showing bogey. They were joined up in sections and the bogeys chased away without any splashes.
The ENTERPRISE lost all communications, VHF, TBS and flag signals but quickly rigged up one VHF channel. During the remainder of that afternoon and night all emergency turns, courses, speeds, and information as to plots on bogeys, locations of friendlies, other Task Groups and picket destroyers were given the ENTERPRISE by this vessel's CIC. This clearly demonstrates the advantage of having emergency VHF radio equipment available for instant use at the pilot house and/or second conn.
On 21 March there were three enemy planes shot down by this Task Group. The first one was picked up at 345º fifty miles on a course of 120º. He disappeared at 090º fifty miles then showed up again at l60º sixty miles on a course of 290º. At 1155 this Nick was splashed by a division of HANCOCK CAP controlled by the U.S.S. SANTE FE for ComCruDiv 16 who was CTG 58.2.9 and located at 220º fifty miles from TG 58.2. This Nick was intercepted at angels .5, speed 230.
The second splash occurred when a Jill closed from 060º forty miles, to twenty miles then opened to the Southeast. He was Tally-Hoed by a SAN JACINTO division, controlled by that base, at 120º forty-five miles, angels six and splashed at 1223 Item, 125º fifty-five miles, angels .5. During this same time a third bogey in the Northeast was being intercepted by HANCOCK CAP controlled by this vessel. The CAP division was kept within four miles of this bandit
National Archives & Records Administration, NARA II College Park, Maryland
Record Group 19, Bureau of Ships General Correspondence Files 1940-45
Transcribed by RESEARCHER @ LARGE. Formatting & Comments Copyright R@L.
Ships Home | Researcher@Large Home