Submarine radio communication had come a long way since its inception near the tum of the 20th Century. The Navy had tackled the technical and organizational problems with the dedication founded in its unique role as protector of maritime safety. By the end of the 1920s improvements in equipment and training were running at high speed.
It was difficult for submarine radiomen to keep up with the ever-changing frequency assignments and the use of non- authorized frequencies was common. Commanding officers were blamed and they, in tum, saw the problem as stemming from inadequately trained personnel. Each submarine was expected to guard two frequencies whenever the submarine’s operating schedule allowed. Surface ships could maintain circuit discipline on a twenty-four hour basis, but the submarines faced many problems peculiar to their mission. These included antenna immersion and grounding of antennas because of defective water seals.
By the 1930s the Navy had established radioman schools with standardized curriculum. Morse Code had to be error free at a speed of 12 words per minute both in terms of sending and receiving. The standard key was used in sending and a manual typewriter (Royal and Underwood) was used in receiving five letter code groups.
Of importance to the Navy communication system was the Federal Communication Commission and the allocation of frequencies to commercial and military use. Commercial broadcast stations became a problem for the Navy when the number of them increased into the thousands. They were concentrated along the coasts and their frequencies overlapped those of the Navy’s shore stations. The Federal Communication Commission sorted out the problem and by the mid 1930s the Navy had the most reliable radio communication network in America.
Immediately prior to the Second World War there were 122,000 personnel in the Navy. Of these 10,500 were engaged in Navy communications including 1,500 officers. On the civilian side, there were 743 licensed commercial radio stations broadcasting to 45,300,000 receivers. By 1944 there were 22,000 officers and 225.000 enlisted men engaged in Naval communications.
As America entered the Second World War, radioman graduates were expected to know the Fleet Communication System which involved the CW nets, teletype and voice communication procedures, the bulk of the three letter Q Codes, internal message routing, communication log maintenance, manual encrypting techniques, teletype machines with tape distributors for further transmission in code, operation of transmitters, and receivers using frequency bands from VLF for submarines, through the middle frequencies to VHF and UHF equipment for aircraft.
Training of war-time radio operators accelerated beyond the limits of Navy schools. Classes were established in certain universities. One such volunteer told of his training, “I went to boot camp at Farragut, Idaho in 1943 during which time I took a battery of mental tests. I scored high and so was admitted to Class A Radioman School, which at the time had a new, experimental program of teaching the Morse Code. The school was at the University of Wisconsin, in Madison. With two men to a dormitory room, life was good. The program taught typing in conjunction with code receipt. The concept was to translate a tone cue into a finger touch without the brain trying to register a particular letter. This worked well with copying five letter word groups in coded material. Since I had known how to type, the training was easier. The school lasted six months. While the minimum code rate was 13 words per minute, the real objective was to copy at a rate of 18 words per minute so that normal Fox and Whiskey schedules could be copied with ease. I was able to pass these tests. After Class A school I was assigned to submarine school at New London and this too was six months. I then was assigned to the USS Atule (SS-403) at New London. Fox came in four times a day. The radio shack was always manned by two men. The radio crew was a chief, a I st class, a 2nd class and two or three 3rd class petty officers. We had to know the fundamentals of 6 the equipment in addition to all the communication skills.”
Prior to the United States entering the Second World War the submarine force became dependent on higher frequencies for reliable long range communication. The use of the higher range frequencies using modified submarine antennas was an improvement over previous frequency use. Accordingly, the Naval Communication Frequency Plan was approved and ship allocation of frequencies according to the original plan changed little through the Second World War.
The TBL became the standard submarine transmitter toward the end of the Second World War. During the latter 1940s and 50s the TBL occupied the forward-starboard comer of the radio space and reached from the deck to the height of a man. The TBL had its motor-generator power supply in the pump room and its massive tubes glowed and hummed when CW was being transmitted. It was actually two transmitters in one. The high frequency power amplifier was located in the upper part of the left hand frame while the medium frequency antenna coupling and tuning system occupied the top portion of the right hand frame. 8 The TBL ‘s components were huge by today’s comparison. For example, it housed coils consisting of evenly-spaced, wound, copper wire over a phenolic tube of about 6 inches diameter. It occurred to more than one radioman of the time that the a few of the seldom-used coils would make fine wine racks, except that bourbon bottles would be more functional. The beauty of such a discovery was the tamper-proof sign on the TBL’s front panel, “Danger – High Voltage.”
By 1943 American submarines were equipped with mast antennae which could receive and transmit while remaining submerged. During the Second World War, Radio Pearl (ComSubPac) received information from American code breakers on the location of Japanese convoys. It then transmitted this information to its submarines for possible interception. 9 Wolf pack tactics, in which several submarines attacked together, required pack submarines to communicate via radio signals emitted on the surf ace. These signals, which could be detected by Japanese surface ships, could reveal the position of the submarines. American submarine tactics gave wolf pack operational control to the wolf pack commander. This divestiture of a centralized control meant that submarines need not transmit over long distance and so preserved the secrecy of the submarines’ location. A VHF stub antenna mounted on the search periscope provided short-range communication with limited detection potential.
In 1941 the Navy conducted extensive tests of loop antenna underwater reception. By 1944 a submarine with her loop antenna 15 to 20 feet below the surface could expect good low-frequency reception at range of 2,000 to 3,000 nm. It was found that very low frequency waves of from 3 to 30 kiloHertz could penetrate sea water up to about 50 feet. Although submerged reception reliability had not been proven, many US submarines during the Second World War continued to use the flat and square loop antennas for periscope depth reception. CW was able to be copied and the smaller loop antennas mounted in the shears were often preferable to long center line antennas.
During the early 1950s the Submarine Force considered three options for prolonged submergence; the closed cycle engine (Swedish Stirling), the Fuel Cell (German Siemens) or Nuclear Power (American Westinghouse). It chose the latter despite the much larger initial design and development period. In the interim, the Submarine Force would utilize its Fleet Type submarines with modifications stemming from advanced German World War II designs. These modifications included a snorkel, doubling of battery size (from 126 cells to 252 cells), streamlining of the superstructure and fair water and accommodation of an advanced chin-mounted sonar array. These converted boats were called GUPPIES for Greater Underwater Propulsive Power and would represent the backbone of the submarine fleet for two decades.
Improvements in sonar were not paced by communication and fire control, which lagged behind by several years. Certain improvements in radio procedures and equipment did appear in the interim. Accelerated speed transmission was developed after the close of the Second World War and further refined in the decades that followed. Taped messages could “spurt” Morse Code at rates of up to 80 words (five letter code groups) per minute. 12 This reduced the time that a mast antenna had to be exposed when copying Fox and Whiskey broadcasts.
Submarines were required to guard the submarine component of the Whiskey Fleet broadcast, which for submarines, was broadcast every six hours on the odd hours. Submarines also guarded the 0430 Zulu hydro graphic broadcast and the distress frequencies of 500 kilocycles and 8364 kilocycles.
Tactical transmission from submarines became a serious problem when the GUPPIES were assigned sonar platforms ahead of Hunter-Killer groups. These units of ships and submarines operated as ASW forces in response to the growing Soviet submarine threat. While the submarine was the best platform in which to detect a hostile submarine, its difficulty was transmitting information. A surface ship was normally stationed close by the submarine so that short-range, underwater, UQC telephone communication could be used. A partial solution for Hunter-Killer submarine-to-battle group communication was the radio buoy, which transmitted a predated message, after having been released from the submarine. Another partial solution was for the submarine to raise its mast and transmit on a per-arranged two hour schedule. This necessitated the submarine to keep a significant distance ahead of the Hunter-Killer Group and to compromise its location on a regular basis.
The standard submarine communications radio transmitters and receivers found on USS SIRAGO (SS-485) in 1959 were: the TBL transmitter operating on frequencies from 175 to 18,100 kilocycles with a 220 volt DC power supply emitting 200 watts with CW or 50 watts voice, the TCZ transmitter operating on frequencies from 3 00 to 600/ 2000 to 18, 100 kilocycles with a 120 volt AC power supply emitting 90 watts, and the TED transmitter operating on frequencies of 225 to 400 megacycles with a 120 volt 60 cycle AC power supply emitting 40 watts on CW or 20 watts on voice. Receivers included the RAK which covered 15 to 600 kilocycles, the RBS which covered 2 to 20 megacycles, and the RAL which covered .3 to 23 megacycles, all using 120 volts 60 cycle AC. These were the major components of a GUPPY submarine during the 1950s; however, other transmitters and receivers were also used. The TBL transmitter was remarkable in that its tenure of service was from about 1944 to the end of the 1960s. It consisted of two frames bolted together and mounted in a single base.
The SIRAGO, a GUPPY II, had several whip antennas, which could be raised on masts while running at periscope depth. The snorkel also had a small whip antenna. Most submarines of the time had a VLF loop antenna, the AT-317/BRR. This was normally used with the RAK receiver while running at periscope depth. The UHF AS-468/B antenna on a retractable mast was used with the AN/URR-13A receiver and the TED transmitter. 14 As antennas were added to GUPPY sails, the number of grounds increased from leaks. A spring-loaded, side-mounted whip antenna was designed to fold backwards and lie horizontally when the submarine dove. It performed as designed, but the pivot point necessitated flexing of the lead. Seals and packing glands failed with depressing regularity. Electronics technicians and radiomen climbed the sail to make repairs, but despite their best efforts the antenna was often inoperable. Once seawater entered the stainless steel webbing embedded in the neoprene insulating sheath no amount of alcohol could remedy the problem. In addition, leaks were often encountered as violations of the pressure hull. Submarine radio equipment was often subjected to seawater incursion. This chronic problem was a result of failing antenna lead connections, antenna trunk leaks and leaking pipes that ran through the overhead of the radio spaces.
One potentially disastrous event occurred during the 1950s when the USS CARBONARO (SS-337) got underway after a yard overhaul. On the boat’s first trim dive a sudden jet of sea water blasted into the boat’s radio room from the overhead. At sixty feet the one-inch hole hosed seawater on equipment and radiomen. Located in the rear quadrant of the control room the radiomen’s cry of, “Flooding in radio!” resulted in an immediate surfacing. It didn’t take long to discover that the hole had been drilled by a yard worker for an intended antenna lead. It had been taped over and painted by unknown parties in the shipyard. The amazed radiomen wondered how tape and paint could have held back sea pressure down to 60 feet. The story didn’t end there. The chief radioman removed the soaked TCZ transceiver and carried it back to the crew’s head. He placed it on the shower floor and immersed the receiver in fresh water. He then carried the receiver back to the engine room and placed it under the engine air induction. After two days of surface operation the receiver was judged to be dry. Tests found no grounds, no shorts and no opens. The chief claimed the receiver worked better after having been so thoroughly cleaned.
The German Type XXI submarine was a revelation to American investigators at the end of the Second World War. A new design moved from the drawing boards to the shipyards. It was the Fast Attack or Tang Class boat. Closely resembling the Type XXI design, it proved to be the test bed for many submarine innovations. While the radio room in GUPPY occupied the space between the periscope wells and the control room’s after bulkhead, the Fast Attack submarine had its radio space in the attack center. This type submarine, lacking a conning tower, had its periscope at the center of the control room which split it into the depth keeping space, on the port side and the attack center on the starboard side. The Tang class boats used a territorial loop antenna AT- 274/BRR.
After the Second World War, NRL developed the much smaller loops, which could be wrapped in a small streamlined body. It was omni directional with two loops wrapped at right angles. Tang class boats had a variety of whip antennas such as the MF/HF retractable whip, NT66053 and the fixed VHF/IFF AS- 524/BPX.15 Submarines were required to guard the submarine component of the Whiskey Fleet broadcast, which for submarines was broadcast every six hours on the odd hours. Submarines also guarded the 0430 Zulu hydro graphic broadcast and the distress frequencies of 500 kilocycles and 8364 kilocycles.
Navy shore radio installations kept pace with submarine improvements during the Second World War and Cold War. For example, by 1922 San Diego was already an active Navy location with several facilities stretching from Point Loma to Coronado Island and the eastern coastline of San Diego Bay. The Eleventh Naval District was housed at the foot of Broadway and the Naval Training Center was built on the tidelands adjacent to Old Town. On this same site the Navy had built the Fleet Radio School. In 1943 the Navy built a new radio receiving station on its property at Imperial Beach. In 1947 this receiver station became the Naval Communications Station, Eleventh Naval District and in 1953 became the Naval Communications Station, San Diego, (NA VCOMSTA).
Retired Chief Warrant Officer and fonder radioman Tommy Robinson recalled his shore-based billet as an RM3, “I was a Radioman at Naval Communications Station, San Francisco, CA (NPG). I stood a split phone watch at the Naval Receiver Site, Skaggs Island, Sonoma, CA, which was shared with the Naval Security Group. We RMs were in a square block building located in the middle of an antenna farm. The building housed receiver banks and operating stations and a teletype link to headquarters in downtown San Francisco. In 1958 Navy primary ship to shore communication was regulated to four frequencies: 4289 KCS, 8578 KCS, 12867 KCS, 17156 KCS, all harmonics. My watch station was a chair, two Royal typewriters, a Morse code key, a set of headphones, note pad and pencil. The object of a split phone watch was to have one CW operator monitoring and receiving messages on two different frequencies, one in each ear. I listened to 4289 KCS in left ear and 8578 KCS in right ear. A knife switch on the Morse code key allowed me to switch between transmitters, one tuned to 4289 KCS and the other to 8578 KCS. An incoming message sequence might have been as follows: Submarine A calls NPG on 4289KCS in left ear. I type the incoming call on my Radio Log, which was inserted into Royal # l, I then insure my CW key is on the correct frequency, and I answer Submarine A’s call. I slip a blank message form in Royal #2 and begin typing Submarine A’s message. But, in the middle of receiving Submarine A’s message a call comes in from Submarine B on 8578KCS in my right ear. I tell Submarine A to wait (AS), switch my key to 8578KCS and ask the precedence of Submarine B’s traffic. If Submarine B’s message is of equal or lesser precedence than that of Submarine A, I tell him, his tum is two (QR Y2). If Submarine B’s traffic is higher precedence than that of Submarine A, then Submarine A’s tum becomes two, even though I have part of that message. QRY lists can get rather lengthy so the job demanded speed and accuracy in sending and receiving.”
Navy schools for radiomen were slow to modify curriculum as equipment and procedural changes were made in the fleet. In 1970, Radioman A School was essentially the same as it had been during the Second World War. Equipment had become more varied, band use had expanded and fleet communication procedures had become more complicated. Radioman Class A School consisted of learning the Morse Code, gaining a familiarity with radio transmission/receiving equipment, learning the Fleet Communication System and learning the basics of encryption/decryption of messages. Radioman Class C School was the advanced portion of radioman training during the 1970s. It was referred to as 2304 School and restricted its students to only those who had demonstrated a high degree of aptitude. Code had to be keyed at not less that 18 words per minute and received at not less that 24 words per minute.