Fighter Direction Spreads from the Carriers - Chapter 9 of Radar and the Fighter Directors

By David L. Boslaugh, Capt USN, Retired

Fighter Directors Ashore

On 7 August 1942 when the First Marine Division went ashore on Guadalcanal, fighters from the carriers Saratoga and Enterprise provided air cover for the invasion force for the first few days. It was realized that assigning fighter directors on the carriers out at sea to control fighters over the beachhead and anchorage was not workable. Instead, a fighter direction team from the carriers was stationed aboard the bombarding cruiser Chicago using improvised facilities and communications. The Japanese did not wait long to send aerial strike forces against the landing, mounting their first heavy raid on the afternoon of the first day, seven August. The first warning was from a Bougainville Island coast watcher, and Chicago’s CXAM operator picked it up at forty-three miles range. There was time to vector eight Wildcats from Saratoga, that tallyhoed at a safe distance away from the anchorage. Later raids that day and on the next were not detected until it was too late for effective fighter defense. Not only was Chicago’s communication on the fighter net shaky, but also the CXAM was operating in a new and radar-unfriendly environment. The cruiser was operating in close proximity to high land masses, and CXAM’s airplane detection over land was not good. An operator who had considerable experience looking for aircraft over a land mass could develop the right techniques to find airplanes, but virtually all CXAM experience had been at sea where the problem was not present.

The Guadalcanal landing was the first major U.S. Navy amphibious operation of WW II, and the senior levels of the Navy realized there was much to learn. Chief of Naval Operations, Admiral Ernest J. King, wrote specifically of fighter direction during the operation:

...lack of an appreciation during planning and preparation of the problem of fighter directing and its attendant communications when other than a carrier acts in this capacity....An experienced and efficient fighter director ship in the immediate vicinity is necessary. There should be an assault commander’s flagship which could handle this function....This ship should coordinate all activities, be the central clearing house, fighter director and be able to send support wherever needed.

It is not efficient use of capital ships to have them remain in the vicinity of an amphibious landing indefinitely for the purpose of fighter direction, and as soon as possible air search radar and fighter directors should be placed ashore. The Guadalcanal operation planners had partially accounted for this by loading an army SCR-270 radar set and supporting technicians (but no trained fighter directors) on one of the transports. The technicians got ashore but, because of a night surface action that depleted protecting surface combatants, the transport was pulled back to Noumea before the radar could be unloaded. Much to their great surprise, the technicians found a Japanese Navy Mark 1 Model 1 air search radar on the island. They tried desperately, but in vain, to get the set operating. In the meantime, Japanese land based aircraft from Buka Island, Buin on Bougainville, and Rabaul on New Britain continued their daily bombing. Without radar, the main source of air raid warnings came by way of radio messages from Australian coast watchers positioned along the Solomon Islands chain. [12, pp.19-20] [9, pp.248-249]

On 20 August, the Henderson Field airstrip was ready, and Wildcats and SBD dive bombers of Marine Air Group (MAG) 23 began coming ashore, but with no radar the marines remained dependent on lookouts and coast watchers for early warning. Earlier in August, the Royal Australian Navy had set up a radio station at Henderson Field to pick up coast watcher warnings and relay them to the defenders. Finally on 2 September, Henderson got its first SCR-270 radar; in a few days joined by two more SCR-270s and two SCR-268s. The 268s were actually army gun fire control radars with range considerably less than the SCR-270, but they could measure target altitude. The SCR-270 had a maximum range of 150 miles on aircraft at high altitude, and the only drawback was land mass that obscured reception in some areas. Combined with the coast watchers, they now had a viable early warning system. Once the radars were ready, marine officer volunteers took on the job of fighter direction with MAG-23 communications officer, Lieutenant Colonel Walter L. J. Bayler, in charge. For a radar plotting table, Bayler used a pilot’s navigation board. Their first facility was an open truck bed equipped with a radio from a written-off Wildcat. When air attack was expected within the hour, the fighter direction team drove to a small hill with a commanding view of the field to practice their trade. [12, p.20] [9, pp.249-250] [34, pp.185-188]

This pilot’s navigation board, officially called the Mark 3A Plotting Board, was standard equipment for carrier pilots. Pilots carried the boards with them to jot down pre-flight briefing information. It was about fifteen inches square and was stored below the instrument panel. In use, the pilot slid it out to make a handy desk for navigation plotting and referencing mission information. He could also flip the top up to store maps and other documents. Many fighter directors in the early days of radar used these boards as their radar plotting table. National Naval Aviation Museum photo

Henderson Field actually had two airstrips. The main airstrip called “Henderson Field” was used by attack aircraft and general aviation, and the second strip about a mile away was a fighter strip called Fighter 1 (which the fighter pilots called the “cow pasture”). A second fighter strip would eventually be built about two miles on the other side of Henderson Field. The first SCR-270 radar was installed on a knoll near the Henderson Field strip, and was called RADAR ONE, On 20 September a second SCR-270 was placed on a rise near Fighter 1, and was dubbed RADAR TWO. It would be used primarily for fighter direction, whereas RADAR ONE would support the local AA battery of twelve guns. In late September, Major Joseph N. Renner, supported by a team of marine enlisted radar technicians, took over from LTCOL Bayler as FDO. The enlisted team was led by Staff Sergeant Dermot H. MacDonnell who experimented with the tilt feature of the SCR-268 radar and found he could not only get a good estimate of altitude, but could also estimate the size and composition of an incoming raid. He also learned that he could identify an attacker as a Zero by the way its pip jiggled on the A-scope. [34, p.237, p.266]

Finally on 8 October 1942, four trained FDOs led by LT Lewis C. Mattison (USNR) arrived from Pacific Fleet Fighter Director School. Mattinson had been in the first graduating class from CDR Jack Griffin’s Oahu school. By November the FD center had been moved to a dugout with improved radios, and phone lines had been run to the two radar sites and three AA batteries. It would not be until December that there were enough fighters on Guadalcanal to keep up a day-long airborne CAP; instead, they sat on the ground until a raid was imminent. The first raid warning would usually come from a coast watcher. Then, when the radar operators detected the raid, the FDO would scramble fighters. They would spiral upward over the field and would usually reach an altitude of 25,000-to-27, 000 feet before they engaged the attackers. Even though the goal of fighter direction was to intercept as far from the field as possible, that was achieved only on a couple of occasions, the reason being due to the characteristics of the SCR-270 radar. It had excellent 130-to-150 mile detection range, but its antenna mechanism did not allow fine bearing measurement, and the image on the A-scope was not as fine as that of the CXAM. Masking by local land mass was also a problem. It could thus not support precise vectoring, and its best use was long range detection. When the raid came into detection range of the SCR-268 radars the FDO could also give his CAP accurate raid altitudes. Fine tuning of radar and visual observations was sent to the fighters on their way up, and during the intercept. From 20 August to 28 December 1942, the marine fighters brought down 570 Japanese planes at a combat loss of eighty-six of their own. [12, p.20] [9, pp.249-250] [34, p.285]

First Night Fighters Ashore

In mid-November the Japanese scaled back their daylight attacks on Henderson Field, but continued nightly attacks. The available radars did not have the precision for directing night intercepts, and the marines had no radar equipped fighters. Nevertheless, the fighter directors and Wildcats tried night intercepts, but with no success. This began to change in March 1943 when a British ground control intercept (GCI) radar and a radar operator/FDO team of New Zealanders arrived on the island. This radar had already proved during the Battle of Britain that it could support night intercepts. In the meantime, the Army Air Corps had modified a number of A-20 “Havoc” twin-engine light attack bombers as night fighters, designated P-70, and a squadron arrived soon after the GCI radar. The P-70 was fitted with forward firing cannon and a copy of the British Airborne Intercept (AI) Mk IV radar designated SCR-540. Having no GCI combat experience, a team of marine, navy, army and New Zealand FDOs began night intercept experiments with the P-70 pilots, who had never flown a night intercept in anger. On the night of 19 April a navy fighter director, aided both by GCI radar and searchlights directed a P-70 into AI range of a Japanese night harasser who was shot out of the sky. Other than this one success, the P-70s did not have good hunting, largely because they could not match the speed of the Japanese intruders. A further problem was radar and radio equipment that began succumbing to the vicissitudes of island heat, humidity, and jungle fungus. Next, the FDOs experimented with searchlights and Lockheed P-38 twin-engine fighters not fitted with airborne intercept radar. A P-38 would be scrambled as soon as the GCI operators detected a raid, and would rise to intercept altitude where it orbited a searchlight beam. As the raid approached its target the GCI radar would track it continuously and when it was in a favorable intercept position for the P-38, other searchlights would be turned on to illuminate the raider. At the instant of illumination, the FDO would tell the pilot “Bogey Illuminated:” the signal to execute his intercept. A number of attackers were brought down using this technique. [12, p.21]

U.S. Army land based, portable SCR-270. radar. U.S. Army photo by First Lieutenant Harold Zahl, Source: http://www.monmouth.army.mil/historian/photolist

More Daytime Attacks

In February 1943, new Chance-Vought F4U Corsair fighters arrived on Guadalcanal, and on the 11th, flew their first combat mission. In April, May, and June 1943 the Japanese mounted three major daylight raids against Henderson Field, which again demonstrated the British GCI sets capability, as well as the climbing ability and firepower of the new fighter. Ground interference still made the use of precise vectors for fighter direction difficult, so when the coast watchers warned of a raid, and the radar told the direction from which they were coming, the FDOs told their CAP to position themselves over specified landmarks. This way the FDO knew exactly where his defending fighters were without having to track them with radar, and he could concentrate on tracking the enemy. He could shift his fighters from one geographic point to another and give them altitudes to put them in the raid’s path. By April there were enough new fighters at Henderson that they could have CAP airborne all during the day, and the Corsair’s climbing ability allowed them to intercept at long ranges from the field, rather than last minute intercepts directly overhead. Fighter direction on Guadalcanal was shifted to the Army in July 1943. [20, p.119] [12, p.21]

Fighter Direction Spreads to the Cruisers

Even though Admiral Nimitz had coined the phrase “Combat Operations Center,” which was to be set up in every Pacific Fleet combatant, some of his senior officers bridled at the new name. They protested that the bridge is, and always has been, the combat operations center. The complaints were so loud that they eventually got to the Chief of Naval Operations, who in January 1943 directed that the new facility be called the “Combat Information Center (CIC).” In that same month the new SK radar began appearing in the fleet. It was made up of a modified SC radar using the large CXAM-1 antenna, and it had a built-in PPI display in addition to the A-scope. The SK radar, developed at the Naval Research Lab and built by General Electric Co., would be the Navy’s best long range radar from 1943 to the end of the war. The first model used a fifteen by fifteen-foot planar type antenna, but later, a fifteen-foot diameter paraboloid, was placed on larger ships. It would be the fleet’s first radar to give a detection range of 140 miles on average-size aircraft. It had provision for IFF attachment, and in addition to the PPI scope built into the operator’s console it could support remote PPIs. The PPI in the operator’s console was a great step forward in quickly determining range and bearing, but target information still had to be transmitted to the FDO by phone or messenger. Sailors soon solved that step by laying a circular sheet of tracing paper over the PPI and marking the locations of the glowing pips, as well as marking a bearing indicator and the range scale. In seconds, these “cookies” would be rushed to the fighter direction plotters. This would be a stopgap until remote PPI repeaters were installed in CICs so that FDOs could run an intercept by a series of glowing grease pencil marks, indicating the tracks of the target and interceptor, directly on the PPI face. [9, p.237] [23, pp.183-186] [6, pp.44-45]

The Chance Vought F4U Corsair, at high speed, out-performed the Zero in rate of climb, speed, and maneuverability. The Zero had better maneuverability at low speeds so Corsair pilots avoided low speed combat. The Corsair’s engine was so powerful that it needed a thirteen-foot propeller, which necessitated the inverted gull wing to keep the landing gear at workable length. U. S. Navy photo, National Museum of Naval Aviation No. 1986.145.002
Artist’s depiction of an SK radar in a battleship. It was built for large combatants by combining an SC radar with the improved CXAM-1 antenna. From FTP 217 p.16

In early 1943, the Allies continued their push to take Japanese held islands in the Solomons, as well as New Guinea. Invasion forces were moving into waters without much maneuvering room, as well as closer to large Japanese bases. It was not a good idea to bring fleet carriers into such waters where they were within the enemy’s aerial striking distance. Enterprise’s skipper wrote:

During the past month the strategic situation had required long continued presence of carrier task forces in limited areas within at least approximate range of the enemy. Such risks...should...be minimized in every possible way
.

The first solution was moving fighter direction to cruisers supporting landings, and providing CAP from island bases such as Guadalcanal, or from smaller escort carriers.

One of the first such operations, the bombardment of Munda airfield on New Georgia Island on 4/5 January 1943, revealed a weakness in IFF. The cruiser Nashville was assigned fighter direction but failed to detect a Japanese raid that came in above and close behind its own combat air patrol that was showing IFF. It was found that an aircraft located less than five degrees in bearing on either side of a plane showing IFF, and at a similar range would appear on the radar scope as a friendly IFF response. The CO of the cruiser Helena recorded: “ It is probable that IFF signals from our covering planes prevented radar detection.” The cruiser Nashville fared a little better when it ran fighter direction on 23-24 January during the bombardment of the airstrip at Vila-Stanmore on Kolombangara Island. The task force had been shadowed by snoopers that were never intercepted, even though they were seen by the ships’ lookouts. There were no daylight attacks on the force, and a night torpedo plane attack was thwarted. In his action report, Commander Task Force 67 wrote:

...our excellent fighter coverage of from 7 to 12 planes undoubtedly prevented us from being attacked on the 23rd. I have no doubt that the Japs would have sent in an attack had their trailers reported that we were lacking fighter cover.

Of the failure to intercept the snoopers, the task force commander wrote, “Fighter Direction and attendant communication still show room for improvement.” [12, p.22]

A tragic incident on 29 and 30 January 1943 again showed the negative value of radio silence when it is most likely that the enemy already knows of your presence. On the 29th, the cruisers Chicago and Wichita were escorting a reinforcement convoy protected by fighters from Enterprise and the escort carriers Chenango and Suwannee, and enemy snoopers were apparently tailing the force. CINCPAC had even messaged intelligence to the OTC that trailers were probably on his tail. The FDO on Wichita, who had fighter control and was keeping a detailed plot of the unidentified planes, requested permission of the OTC to use the fighter net to send protecting CAP to intercept the bogies. Hesitant to break radio silence, the OTC elected instead to launch a fighter division from one of the carriers, without fighter direction, to find the snoopers and identify them. In his mind they were most likely friendlies not showing IFF, and he doubted enemy airplanes were nearby. At nightfall, the searchers returned to the carrier and reported no contact, but that night Japanese torpedo planes attacked, putting a torpedo into Chicago. The cruiser remained afloat, and the cruiser Louisville took her under tow, transferring the tow to the ocean going tug Navajo the next day. Even though the ship was under strong air cover, Japanese torpedo planes again attacked Chicago without being detected, and in spite of heavy Japanese aircraft losses, hit her with four torpedoes, sending the cruiser under.

Of the loss, Commander South Pacific Area (COMSOPAC), Vice Admiral Halsey, noted that the non-use of fighter direction communications contributed to Chicago’s sinking. He continued:

There should be no hesitancy to break radio silence for direction of fighters under these circumstances....If the enemy already has the information, as indicated in this case by the presence of enemy planes in the area and by the ultimate attack, the imposition of radio silence is unsound.

Halsey went on to complain that if the FDO had “super frequency [VHF]” radios there would have been no concern about breaking radio silence. He wrote:

For over a year recommendations have been made, based on combat experience, for the production of ultra high frequency and multi channel, quick shift radio equipment. To date operating forces are still suffering from most unsatisfactory equipment.

About the use of IFF, COMSOPAC observed that if all friendly planes could be counted on to use IFF at all times, the OTC would have known that the unidentified trailers were enemy. He stated the problem was “neglect on the part of aircraft units to provide proper maintenance and continuous adjustments of the equipment” and also because of “pilots not keeping IFF turned on throughout each flight.” Reflecting on the inability to detect the second attack on Chicago, Admiral Nimitz wrote:

It is axiomatic that all planes in the vicinity of the task force must be continuously tracked and plotted and information on our own planes continuously disseminated to the forces. A properly run combat information center as prescribed in 4TB42 should eliminate most of the foregoing deficiencies.

[12, pp.22-23]

Fighter Direction Moves to the Destroyers

Fighter direction from cruisers had not worked out too well; furthermore, cruisers with their big guns were in demand for other work such as shore bombardment and surface engagement. The fleet was now getting new destroyers with SC-2 radar and well equipped CICs that could function as well or better than the improvised CICs on the older cruisers. To provide fighter direction to cover the invasion of Rendova Island in June 1943, the new Fletcher Class destroyer Jenkins embarked a team of four FDOs and two enlisted operators at Guadalcanal. Land based fighters were to provide the CAP. After the landing, Jenkins’ skipper noted in his action report that the team had performed extremely well. He reported that they had intercepted all enemy air raiders before they reached attack position, and in the final attack a few torpedo planes did get through, but the ships guns easily dealt with them. He wrote:

The net results in planes lost versus one torpedo hit on an unloaded transport must be rather discouraging to Jap naval air power. It is believed that if the combat air patrol is adequate, interception can be made in sufficient time to neutralize an attack: the problem appears to be that of providing sufficient fighters rather than improving radars.

In his action report, Admiral Halsey noted ”The results obtained by the fighter director unit, hastily assembled on board the USS Jenkins and working in an area partly enclosed by land, are very encouraging. Rapid developments along these lines will be highly remunerative.” From that time on, fighter direction teams would be assigned to destroyers supporting invasions throughout the Pacific. Size and makeup of these teams were determined by availability of trained personnel, but they were usually composed of two FDOs, a few radar operators having specific experience in supporting fighter direction, a radio man, and if available an equipment repair technician. Not all destroyers had the latest radio gear so many times the teams brought their own radio equipment, and they usually had to share bunks with ship’s company, or sleep in passageways or the wardroom. [12, pp.23-24]

By September 1943 there were sufficient Mark III IFF sets in the fleet to dispense with the Mark II equipment that operated on the same frequencies as the radars. The Mark III had its own assigned frequency, and its own antenna, which was usually mounted on top of the search radar antenna. The Mark II equipment had the same bearing discrimination as the search radar to which it was attached, however, the Mark III discrimination was not quite as sharp as the search radar. To make up for this, it could detect one of seven codes set up in an aircraft. For example, this would allow controlled fighters to be identified separately from other friendly aircraft. Another use of the codes was to identify a specific plane such as the flight leader in a group. Not all destroyers had the latest SC-2 radar, some still having older SC, SC-1, or SA radars. Some of these had an early omnidirectional IFF antenna that when used to interrogate an aircraft and when that plane responded as friendly it would show all planes at that range as friendly regardless of bearing. This sometimes caused enemy planes to be identified as friendly. The destroyer Sauffley, in November 1943, had an embarked fighter direction team aboard to support the Bougainville landing. The commanding officer, in his action report noted that the team had experienced problems with his older SC radar:

Because of the marked difference in the performance of the various types of search radars, it is recommended that Fighter Director units be assigned to ships with SC-2 radar. The reason for this recommendation is based on the fact that SC-2 radar is the only one having directional IFF, which permits quicker discrimination between friendly and enemy units.

Sometimes there was friction between embarked FD teams and skippers. A case in point was the team assigned to the destroyer Pringle to support the Bougainville landing. The FDO had twice requested the CO to use the ship’s radio to request advance information regarding expected tactics and strength of the Japanese forces, plans of Allied surface and aviation forces, and specific information on the air squadrons with whom he would be working. Even though the ship was equipped with a new line of sight VHF radio, the skipper refused to break radio silence. The fighter director would not be permitted to transmit until he had a definite bogey on his radar. The FDO wrote in his action report.

Much valuable time... is lost in checking with his cover, finding out their calls, their positions and their angels (altitude). The fighter director should have all this information at his fingertips prior to the appearance of the bogey so that an immediate vector for proper intercept can be given.

The FDO often had to work near land which masked airplanes, and also allowed Japanese pilots to fly low behind mountains and hills where they were undetectable until close to forces afloat. In such circumstances the radar operators were doing very well to detect a raid at fifty to sixty miles. Commander Destroyer Squadron 22, in an action report regarding an August 1943 convoy to Vella Lavella Island noted “...due to land interference the SC radar was of little use. The enemy was apparently fully aware of our difficulty in detecting his approach and used various islands as a screen against radar detection.” [12, pp.24-25]

The destroyer FDOs had other problems. Carrier FDOs usually got to know their pilots well, which facilitated their working together and setting up procedures that all understood. There was not this advantage of personal contact for the destroyer fighter director. Furthermore, pilots occasionally did not keep destroyer FDOs informed as called for by standard procedures, and sometimes they did not turn on their IFF gear. During the Green Islands landing the FDOs did not have enough fighters to put a CAP over each group of transports, and the FDOs were kept busy shifting fighters to unprotected transports under air attack. The FDO assigned to the destroyer Sigourney urged that each transport group be assigned a dedicated CAP. The destroyer FDO teams also had the problem of potential burnout. After the November Bougainville landing, the CO of the destroyer Saufley reported:

The Fighter Director units with which we have worked have turned in excellent performances and have proven the value of these units during the current operations. Inasmuch as four of these units have handled all the fighter direction since the beginning of the current operations and some of these units have made an average of twenty or more consecutive trips, it would seem highly desirable that additional units be employed to permit a system of rotation which will provide occasional periods of relaxation.

Normally, when proceeding to or from a landing operation, the destroyer FDOs kept their CAP overhead, but when the CAP was operating over an invasion beach, the landmark system that worked well on Guadalcanal was employed. The fighter director would send his fighters to a well defined geographical point in front of a raid and have his CAP orbit there and wait. As the Pacific campaign moved westward, more new destroyers joined the fleet. They had well equipped CICs and the newest radars. The new CICs were larger and located where curious interlopers would have a hard time intruding. The new destroyer CICs and radars were thus more capable than the equippage on the older cruisers for the conduct of fighter direction. The Japanese, at one point, made an all out attempt to repulse the Bougainville invasion with a raid of one hundred-plus planes. In his action report, Commander, Third Amphibious Force said:

A special tribute is due to the training and aggressive spirit of our fighter pilots and the skill of our fighter director crews. Every attempt to push through in force to striking distance of the convoy was met with an opposing group of fighter aircraft. Without this protection losses might have been enormous. As in all recent operations in this area fighter direction was conducted from destroyers.

[12, p.25]

The Argus Advance Base Units

The lessons learned in the early days of fighter direction at Guadalcanal were not lost. Senior Navy planners realized that specially trained and equipped units were needed to go ashore with amphibious landing forces to provide quick radar surveillance, combat information center functions and fighter direction. The concept was they would be trained as cohesive units ashore many months before a landing; and they would have their own radio, radar, and other equipment to provide a self sufficient capability. The Greek mythical Argus was an all-seeing giant with many eyes, as many as one hundred in some stories. Not all of these eyes slept at the same time so Argus had vision at all times. It was not too much of a stretch then to name a specialized radar unit “Argus.” Most of the Argus equipment would be trailer and truck mounted Army Signal Corps gear. The Navy would provide an SC-2 radar in a trailer as well as a small truck-mounted microwave SQ surface search radar. To support the earliest stages of a landing, small portable radars, such as the SN and SQ, would be used until the large army radars could be brought ashore, set up, linked together with communications, and provided with a central CIC.

Artist’s depiction of a portable SQ microwave radar set. SN and SQ sets could be carried ashore by a few men. Both types could show range and bearing, and the SQ could be connected to IFF equipment. The SN had only an A-scope, but the SQ could show either A-scope or PPI format on the same indicator. From FTP 217 p. 26

Argus unit training was set up at the Advance Base Depot, Port Hueneme, California. Training started in October 1942 with five officers who were to help set up the program and then to ship out with the first unit: Argus Unit 1. The first commanding officer, LCDR Ralph A. Jack, oversaw training including radar plotting, radio operation, use of Army SCR-588 and 270 radar sets, and CIC operation. Next, they practiced setting up their equipment and running air intercept drills. As a graduation exercise the unit boarded a landing ship, tank (LST), and stormed San Clemente Island off the California coast where they again set up the system and for a month practiced their entire training syllabus of air intercepts, AA battery control, air raid warning, homing lost pilots, snooper detection and elimination, crash boat control, and maintaining a complete and current air and surface intelligence picture. Then in April 1943, under the command of LCDR Jack, the twenty officers and ninety-four enlisted men of Argus Unit 1 boarded ship for the South Pacific.

On 30 June 1943, seven officers and thirty enlisted of the unit went ashore as an advance echelon on Woodlark Island in the Solomon Sea. They brought with them a small SCR-602 air search radar packed in wooden crates. They set up the radar, established a CIC in a tent, set up a radio tent, and began assuming fighter direction from destroyers offshore. Their first job was to detect enemy air and surface attacks and warn the island’s garrison. Once the invasion perimeter was secure the remainder of Argus Unit 1 came ashore with the larger truck and trailer mounted equipment. Communication lines were run to nearby AA and searchlight batteries, a Patrol Torpedo (PT) boat squadron, and crash boat piers. Later, a navy construction battalion built them a fairly large wooden building with raised balcony so that intercept control plotters could look down on a large map table showing the island, its environs, the air and surface situation, and other intelligence information. The map table featured the gridded coordinate system used by the Army rather than the navy polar coordinate system. A radio room with ten receivers and two transmitters was also located in the building. For the first few days of the invasion, fighter protection came from aircraft carriers, but, when the nearby airfield was ready, overhead protection was shifted to the Army 5th Fighter Command. The Woodlark landing had been uncontested, and Japanese air counter strikes came only at night. Target altitude measurement was essential for night fighter direction, but since the unit had no height finding radar they resorted, without success, to searchlights for CAP direction.

On 30 June 1943, Argus Unit 11 sent an advance echelon in with the Rendova Island invasion, but this time with opposition, and suffering casualties. They initially had only a portable SCR-602 radar, and, because the FDO on the destroyer Jenkins had to temporarily go off the air, they had to start fighter direction over the invasion beach almost immediately. They later brought their heavy equipment ashore under strong bombing and strafing attacks that lasted a number of weeks, and they did their fighter direction from their radio truck until a more protected dugout could be prepared. By August, a larger CIC and a warning net had been set up at nearby Munda on the Island of New Georgia where they took over Argus Unit 11’s work. Throughout the Pacific Campaign, Argus units went ashore in other landings including the following:

  • In the Solomons
    • Green Islands
    • Bougainville
    • Treasury Islands
  • In the Bismarcks
    • Emiaru
  • In the Ellice Islands
    • Nanumea
    • Nukufetau
  • In the Gilberts
    • Tarawa
    • Apamama
  • In the Marshalls
    • Majuro
    • Eniwetok
    • Kwajelein
  • In the Marianas
    • Tinian
    • Guam
  • In the Carolines
    • Palau
    • Ulithi

When not directing fighters in combat, the Argus units gave fighter squadrons valuable practice in air intercepts. The work of the Argus units was temporary until their army or marine hosts could set up permanent command, fighter direction, and warning facilities. When relieved, the Argus unit would pull out and prepare for the next invasion. [12, pp.25-26] [60]

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