A collaborative effort between historical reenactors of how to use the SCR-300 Radio for World War Two Reenactments.
The SCR-300 Radio is a backpack (or manpacked) FM radio designed during WW2 as an inter-company or regiment radio. I purchased several in the late 1990s during the heyday of Cold War surplus sales.
Several years ago I worked with a buddy of mine to make available a resource that World War Two SCR-300 enthusiasts could use to analyze and learn about the radio. The article is posted on his website:
Differences Between Models
The SCR-300 came in two types, an A and a B. The different models are identified on the data plate. There’s no operational difference between the two types. The differences lie in the parts. For example, different resistors are used and parts are moved around or dropped. Page 5 of TM-11-4024 Radio Receiver and Transmitters BC1000-A and BC1000-B Repair Instructions (Aug 1945) describes this more (note that this TM doesn’t seem to exist as a PDF on the internet) –
SCR-300 Organizational Placement
The Infantry School Mailing List, Oct 1946 has a chapter on the Infantry Radio Communication and describes usage of the radio, pros and cons (particularly as it relates to range and batteries) as well as where the radios get placed in an organization.
On page 149 it describes the SCR-536 (BC-611 aka “Walkie Talkie”). While not the SCR-300 (BC-1000) it’s often seen in conjunction with it –
“The SCR- 536 is a low-power voice radio set. It is designed for two-way communication up to ranges of one mile. Total weight of the set, including batteries and all equipment necessary for transmission and reception contained in one aluminum case, is five and one-half pounds. The set is crystal controlled for both reception and transmission and operates over frequency range of 3,500 to 6,000 kilocycles . Each unit is adjusted to work on only one frequency. (A radio technician can alter the frequency of the set by changing crystals and certain other parts. ) The distribution of the SCR- 536 within the Infantry regi- ment is seven per rifle company and six per heavy weapons company. The principal employment is for maintaining communications from platoon headquarters to company headquarters ; however, they are also suitable for maintain- ing contact with observation posts , outposts and patrols if distances involved are not too great. This set is simple to operate and takes no special training other than learning the correct voice- radio procedure. It is automatically turned on when the lower section of the an- tenna is extended . It should be operated with the antenna fully extended and in an upright position . ( Operation of the set is seriously hampered when the antenna comes in contact with foliage of trees . ) Life of the batteries is normally fifteen hours. When either battery runs down, both should be replaced . The set should be kept as dry as possible at all times as excessive moisture will render it inoperative. While rugged in construction, the SCR- 536 should be handled with care as it is not shockproof.”
On page 152 it describes the SCR-300 usage
The SCR-300 is a low- power, portable radio set designed for two-way voice communication over short ranges. The set comes equipped with two types of antennas which are commonly referred to as the long and short antennas. The rated range of the set with the long antenna is three miles or over, depending on operating conditions. The range of the set with the short antenna is slightly less . The short antenna should always be used while operating on the move as the set may be seriously damaged if the long antenna catches on low branches or other obstructions . When operat- ing from a fixed position, however, the long antenna will produce the best results. The short antenna has a flexible section which enables it to be adjusted to an upright posi- tion. The SCR-300 has 41 channels operating over a frequency of 40 to 48 megacycles ( 40,000 to 48,000 kilocycles ) . Each set is hand calibrated at the time of manufacture, thus assuring a high degree of accuracy of tuning by channel setting. The distribution of the SCR-300 is as follows : One……. per rifle company. Five… ..per heavy weapons company. Five… ..per antitank company. Five….. Three… per cannon company. per battalion headquarters company. Twenty-three….. per regimental headquarters company. In the rifle company, the SCR-300 operates in the battalion command net. The five SCR-300s of the heavy weapons company may be used in several different ways, depending on the communication requirements of the company and battalion . The following is an accepted disposition :
A. One with the company commander who is usually near or with the battalion commander. B. One at the mortar position of the 81 -mm mortar platoon. C. One with each of two forward observers for the 81-mm mortars. D. One with the gun platoon. In this case the five heavy weapons company SCR- 300s would be on the same channel and would comprise the heavy weapons company net.
The three SCR-300s of the battalion headquarters company may be distributed as follows : A. One set at the battalion command post. B. One set with the battalion commander. C. One set to be used as a utility set and sent where needed. The battalion command net will then consist of the three rifle companies’ radios, the battalion command post radio, and the battalion commander’s radio. All sets will necessarily operate on the same channel setting.
As the SCR-300s in both the antitank and cannon company are employed in a like manner, only their normal dis- distribution in the antitank company will be discussed. The five SCR-300s may be used to advantage in the following manner : A. One set with the company commander. B. One at the company command post. C. One with each of the three platoon leaders. The command nets of both antitank and cannon companies will then be composed of the company commander, company command post and the three platoon leaders . ( Each of the nine tanks and the tank recovery vehicles are equipped with AN/VRC-3’s . )
The 23 SCR-300s of the regimental headquarters company may be employed as follows : A. One with the counterfire officer and three with each of the three counterfire squads. This accounts for ten sets and would comprise the counterfire net. B. The regimental S-2 net requires five sets ; one with the S-2, one with each of the three squads of the I & R pla- toon and one utility set. C. The air-ground net is made up of the ground set at the regimental command post and the set mounted in the liaison plane. D.
The above allocation leaves a total of six utility SCR- 300s to be employed as required or used as replacement sets. The SCR- 300 has proved to be of outstanding merit. It is the first of the Infantry sets to use FM ( frequency modulation). Although the subject of frequency modulation is beyond the scope of this article, it is worth noting that FM is finding even greater application in newer military radio sets. “
Radio and Telephone Procedure
For a full breakdown of how to communicate over radios and telephones please refer to: FM 24-9 BASIC FIELD MANUAL COMBINED UNITED STATES-BRITISH RADIOTELEPHONE (R/T) PROCEDURE UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1942.
BC-1000 Control Panel Fasteners
BC-1000 Control Panel Fasteners – This is a pdf that covers how to add new washers, seals, nuts, and screws to the front panel. Looks to be about 8 different screw assemblies.
NOTES from TM 11-242 on the SCR-300 Wired Loops and Battery Case Catches
The SCR-300 originally came with wired clips. This is according to TM 11-242, 1943. See below
A work order was made in Nov of 1944 for spring catches
This was then replaced with a New Latch Directive in Jan 1945. The wired loops would fail to hold down the clip so a spring catch was added.
SCR-300 Radio Set: The Development, Operational Employment, and Details of the Famous “Walkie-Talkie”
Mike Roof, SGM, USA (ret.) wrote a 200-page guide on the development of the radio set which includes great discussions of some of the early war development and post-war variants. As well as new images of the SCR-300 in WW2. Worth checking out to learn a bit more about the unit. He originally posted it in the G503 forum but it looks like space might be an issue for him so I re-posted it here.
Combat Lessons
Below are some nuggets of information regarding Radio Security and Lessons Learned while using Radios in World War Two. It was taken from Hardscrabble Farm and reposted here.
Combat Lessons 3: The snippets below come from this guide. You can find the full guide via a pdf which contains a variety of information at my Combat Lessons and Army Talks Post.
Common Violations of Radio Security Brigadier General Richard B. Moran, Chief Signal Officer, Fifth Army, Italy: “Use of proper names, Christian names, nicknames, etc. to refer to an officer or enlisted man defeats the object of daily changing code signs and helps to identify groups. The authorized code or codex must be used.
“Use of unauthorized code names or codewords may cause confusion. Units may not allot them without permission.
“Long transmissions give the enemy plenty of time to tune in and increases his chances of gleaning information. Keep ‘off the air’ if possible. Keep transmissions short.
“An encoded map reference must not be accompanied by a description of the place referred to.
“Administrative reports must not be sent in the clear. The enemy can often obtain valuable information from them.
“Codex is more secure than the reference-point code and its use should be encouraged.”
Disclosed by Your Code Official Report, Signal Operations, Sicily: “The continued use by an organization of a code of their own making will easily identify that unit wherever and whenever it moves. Members of a unit captured by the enemy disclose the unit designation. As long as the unit uses its special-type code its identification is certain.”
Combat Radio Log
This is a pdf of a Radio Log by the 60th Infantry Regiment of the 9th Infantry Division between Sept 14th to Sept 21st. This was part of the attack through the Huertegen Forest. This kind of radio log probably wouldn’t have been transcribed by an SCR-300 radioman but it gives an idea of radio communication in an actual combat situation.
This looks like regimental-level radio traffic as the operator interacts with different units such as Nudge, Notorious, Red, Blue, Nomad etc. Many have a numbered suffix at the end like “Nutmeg 3” or “Blue 3” suggesting they are part of the same radio traffic net and are either a specific person or unit (like a battalion or company) within the said net.
In looking at it I think when the mention Nutmeg Red or Nutmeg White or Nutmeg Blue (etc) it’s likely the regimental or battalion and Nutmeg Blue 2 (for example) is some additional subdivision like battalion or company?
The 84th Infantry Division Signal Operation Instructions for Radio and Telephone standard operating procedures goes into a bit more detail about how call signs work on both radio and telephone. It approximates the radio log of the 60th. Namely, the Signal Officer assigns the code names, frequencies, and effective dates, and provides for the radio and telephone equipment. If a subdivision is needed they refer to it as a color and if an additional subdivision is needed, they use a letter.
So if I’m using an SCR-536 at the regimental level and I want to contact the D company of the 1st battalion of the 334th Infantry Regiment I could tune to the frequency and say something like ” This is Chow contacting Chisel Blue D”
Note that telephone would be utilized over radio (but uses a similar communication style) unless the officer thinks radio warrants it or they need it for an emergency.
For a listing of Military Code Names in Europe see: Military Code Names for the full listing or this Excel sheet for a breakdown by division. I’m not sure if it’s all of them or if these were dynamic and changed but it’s a piece of paperwork someone would’ve had. These codenames were likely at an Army or Corps level echelon as opposed to a division or regiment or battalion or company.
They also describe the various positions of the units as they move forward clearing out bunkers and pill-boxes. At one point they make mention of losing the slidex which is a handheld encryption device.
For reference the following units are
Nutmeg = 60th Infantry Regiment
Nostrum = 9th Medical Battalion
Notorious = 9th Infantry Division
Noxema = 15th Engineer Battalion
Nudge = 39th Infantry Regiment
Nuptial = 60th Field Artillery Battalion
Nostril = 47th Infanry Regiment
Omaha = 3rd Armored Division
Jacket = 4th Cav Group
Jingle = 438th AAA AW Bn M. Meaning it’s the 438th Anti-Aircraft Artillery, Auto-Weapon Battalion, Mobile. I’m not sure what the “auto-weapon” the unit had is supposed to be.
Jungle = ?
Batteries
The SCR-300 batteries came as a BA-70 which is the standard model and a BA-80 which is a lightweight model. There’s no difference between them only the BA-70 has a longer life. The battery would be plugged into the bottom case.
Orignal BA-70 photos
Reproduction BA-70 Photos
There is a guy out of Italy who makes them. If I recall who it is I’ll post the information. The reproduced batteries look like the following –
Note, if you’re looking for batteries for your SCR536/BC-611 it looks like a company out of the UK has working reproduction ones available.
BA-23 and BA-30
Hardscrabble Farm has a write-up on Batteries: BA-23 and BA-30. These aren’t used in the SCR300 but I posted them here as they are commonly used with various Signal Corps telephone and radio equipment. BA-30 is the equivalent of a D battery. These would’ve seen usage in the EE-8 field phones and switchboards like BA-71 and 72.
Crystals
Radios in WW2 and in some post-war models like the PRC6 used crystals. CR is the Army nomenclature for the crystal. Several different kinds existed such as CR-18U and CR-23U. The numbers at the end likely refer to the type of crystal structure.
The crystal structure would give an indication of how well the drive, power, ohm level, and oscillation of the crystal would perform. For a complete breakdown of the science behind it, you can refer to: HANDBOOK OF PIEZOELECTRIC CRYSTALS FOR RADIO EQUIPMENT DESIGNERS by John P. Buchanan, Philco Corporation, October 1956. It’s a 700-page tome!
The crystals were then cut to oscillate at certain frequencies. They were then stored in signal corp metal cases typically starting with CS or CY.
The video below discusses How Crystals Go to War and shows the manufacturing process.
For an excellent short history of the crystal industry in the US up to the end of the Korean War see: A History of the Quartz Crystal Industry in the USA published by the UFFC the organizing body to set standards for crystals today.
Where to Purchase
I’m occasionally asked where to purchase the radios. Ebay is a good online place to find it. You could also look around on Facebook Marketplace or use an older one like Craigslist.
PRC68 is a website that lists military communication equipment and has loads of links for surplus dealers. A lot go to a 404 but you might get lucky and stumble across a website that has one for sale. International Military Antiques is another place but you’re likely to pay above market value for it.
Online forums like the G503 is a place to find equipment. You’ll need to make an account.
You can visit surplus dealers either brick and mortar (the US Militaria forum has an active list) or follow a bunch of online-only stores on Facebook and hope one shows up.
Lastly, you can visit shows such as your local militaria show or the larger ones like Show of Shows or The Max.
