SCR-300 Walkie-Talkie Radio Set

 

Infantry Marines use the cover of an M4 medium tank for protection during the Saipan campaign, 1944. The radioman carries an SCR-300 USMC Photo

Combat in World War II placed incredible demands on America's fighting forces, and by extension, on the industries that supplied them with arms and equipment. Units were assigned to complex missions across wide distances and they need lightweight, reliable radios.

Prior to the war, the US Navy had been tasked with procuring radio sets for the Marine Corps. But as the war progressed, Marines found that they needed better equipment. They were able to take advantage of work being done by the US Army Signal Corps to develop rugged, simple, and reliable radios designed specifically for ground troops. Among the radio sets procured under this system was the SCR-300 radio set. Although others radios are sometimes called "walkie-talkies", this nickname was first given to the SCR-300. The radio was often simply called "the 300".

Galvin Manufacturing, renamed to the more familiar Motorola in 1943, was the prime contractor for this set. During the war, Motorola built more than 50,000 of these radios and the Marine Corps first deployed the SCR-300 for widespread use in the summer of 1944. Thereafter, the new radio became standard and was fielded throughout the Fleet Marine Force in all subsequent campaigns through VJ-Day.

In combat, the 300 proved itself durable, easy to use, and reliable. One of its greatest strengths was its compatibility with tank-mounted FM radios. Units equipped with 300 could talk to tankers on the same frequencies. This critical ability helped to make the Marine tank-infantry team such a potent force in the latter part of the war.

Operation of the SCR-300. US Army illustration from TM 11-242


The SCR-300 was a backpack radio that allowed company and battalion commanders to maintain contact under mobile conditions. This radio set most often served in command groups where it was employed by trained radio operators, but it could be used by almost anyone with minimum training. Technical Manual 11-242 gave the following description of the set:

"Radio Set SCR-300-A is a low power, portable, frequency modulated radio receiver and transmitter powered by dry batteries. The set is designed for two-way voice communications over short ranges and is designed primarily for use by combat troops on foot."

Characteristics of the SCR-300 Radio

Weight (complete):  38.23 pounds
Power supply:          BA-70 dry cell battery
Frequency:               FM 40,000-48,000 kilocycles
Channels:                 40 available
Range:                     3 miles (long antenna)
Battery life:              8-12 hours


Components and accessories of the SCR-300. The receiver-transmitter was designated the BC-1000. Combined with the other equipment in this image, it became the SCR-300. US Army illustration from TM 11-242


The SCR-300 was supplied with integral gaskets and flanges to make it waterproof under normal operating conditions. It would stand up to rainy weather so long as the external integrity of the outer case was maintained. But under the harsh demands of the Pacific battlefield, with salt water corrosion, humidity, etc, more extensive waterproofing was sometimes required. This treatment, which called for disassembly of the radio set, was accomplished with spray varnish to seal vulnerable sub-assemblies. During amphibious operations, Marines often simply placed their radios inside sealed waterproof packs during the ship-to-shore phase.

The SCR-300 in its element at a frontline command post on Peleliu, September 1944. USMC Photo


An article in December 1945 issue of The Marine Corps Gazette noted some of strengths and weaknesses of the 300:

"Throughout the Okinawa campaign, the SCR-300 once again proved to be an ideal radio for intra-battalion communication. Its range is appreciably greater in open terrain than it was under jungle conditions, and frequently these sets operated satisfactorily over distances up to four miles. Large land masses still constitute a major obstacle, but often this handicap can be eliminated, or reception at least improved, by shifting the position of one or more sets....Staff officers and company commanders made constant personal use of their SCR-300s. In view of this increasing tendency to use the set as a radio-telephone among officers, the schooling of such officers in simple radio procedures is virtually imperative.

Battery supply is a difficult problem when vehicles cannot keep pace with assaulting elements; replacement batteries should be given priority comparable to that accorded ammunition, food and water. On several occasions during the campaign, air-drops were utilized to deliver batteries.

The simplicity of operation of the SCR-300 proved an important feature during the long operation, as casualties among radio operators were heavy. On several occasions [Marines] previously untrained as operators replaced casualties with a minimum of disruption to radio traffic."

A Marine transmits on his SCR-300 during the fighting on Saipan, 1944. The radio was portable enough that it could be carried by assault troops. USMC Photo


In the Marine infantry battalion, the communications platoon was assigned for administrative purposed to headquarters and service company. Under the F-series Table of Organization, standardized in 1944, one officer and 39 enlisted Marines were assigned to the platoon. A lieutenant, who also served as the battalion communications officer, led the platoon. He was assisted by a technical sergeant, who served as the platoon sergeant, and the communication chief. a corporal was also assigned to the platoon headquarters, and he served as the maintenance and stockroom NCO.

Three sections made up the communications platoon:

Message center and messenger section with eight Marines,
Wire section with fourteen Marines,
Radio, visual, and panel section with fifteen Marines.

A sergeant led the radio section and also acted as the battalion radio chief. Three corporals and eleven non-rated Marines were assigned to the radio section. One of the non-rated Marines was the driver for the battalion radio jeep and ten were radiomen. One of the corporals had the collateral duty of radio mechanic, and two operated radios at the battalion command post.

A Marine transmits on the SCR-300 during the fighting on Iwo Jima, 1945. By this point in the war, the 300 was the primary backpack radio in the Marine rifle company. Still image from USMC motion picture film

In garrison, the radiomen lived and worked in H & S company and the SCR-300s were maintained the communications platoon stockroom. In the field and on operations, radiomen and their sets were attached out to the various subordinate units in the battalion. Usually, each rifle company received one battalion radioman for the company commanders to keep contact with battalion. Weapons company received two radios, one for the company commander and a second for the battalion mortar platoon. The remaining backpack radios were assigned to the battalion command post and to the staff sections.

Top-down view of the BC-1000 receiver-transmitter showing the controls and connection points for headsets and the antenna. US Army illustration from TM 11-242


The SCR-300 radio set filled an critical requirement in the Marine Corps. It proved itself again and again under the harshest conditions in combat and remained in service for several years after the war ended. It was replaced early in the Korean War with the AN/PRC-8 -9 and -10 series of backpack radios. The 300 was the basis for all tactical backpack radios in the post-war era, and it paved the way for communicators. In addition to serving in the Marine Corps, the 300 radio was used by by other branches of the armed forces many allied armies over the years.

BC-1000-A transceiver with basic issue items of the SCR-300-A radio system. Displayed to the viewer's right are the following publications: US Marine Corps Message Book, TM 11-242 (Radio Set SCR-300-A) and TM 11-454 (The Radio Operator). Equipment and publications from the WW2 Gyrene collection


A reconstruction of the SCR-300 in use. This radioman wears the HS-30 headset and transmits with the TS-15 handset. This was a common way to use the radio. The radioman could then listen to all radio calls and have the handset available for his leader to use when needed.

On the Marine's left hip is the BG-150A carrying bag. All components were stowed in this bag when not in use. The bag was also useful for carrying message pads, pencils, etc. Equipment and uniform from the WW2 Gyrene collection


 

Side view of a radioman carrying the SCR-300 radio set. Two antennas were issued with each radio: the AN-130-A with a length of 33" and the AN-131-A (displayed here) with a length of 10' 8".

This Marine wears the basic summer service uniform. While infrequently worn in combat, this uniform was worn in camp, training and garrison throughout the Marine Corps.

Equipment and uniform from the WW2 Gyrene collection


 

 

A radioman in the utility uniform with combat equipment. This was the standard field and combat uniform for most of the war.

Attached to the radio is the AN-130-A antenna. The HS-30 headset stowed in the accessory bag ready for use.

Beneath his radio, this Marine carries the knapsack pack configuration of the M1941 pack. Attached to the pack suspenders, this set-up allowed radiomen to carry personal items along with the radio.

Equipment and uniform from the WW2 Gyrene collection


 

Side view of a radioman carrying the SCR-300 radio set with the AN-130-A antenna. He wears the HS-30 headset under his helmet and the TS-15 handset stowed in the accessory bag ready for use. This was a common way to use the radio in combat when a radioman might need his hands free, for example when equipped with a rifle or carbine.

Beneath his radio, he carries the knapsack pack. Called 'the ass pack' for obvious reasons, the knapsack pack was uncomfortable and Marines only wore it when they absolutely had to.

Equipment and uniform from the WW2 Gyrene collection

 



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Sources used:

Technical Manual 11-242, Radio Set SCR-300-A, w/changes, War Department, 15 June 1943
Fisher, Robert, (December 1945) Communications For Small Units, The Marine Corps Gazette.
US Marine Corps Table of Organization F-4, Headquarters Company, Infantry Battalion, 27 March 1944
http://www.scr300.org/ A website with text and images devoted to the SCR-300 radio set (accessed 26 June 2010)

 

 

 

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