TRANS1.'ISSION SECURITY TRAINING 

Somewhere in North Africa a pilot returning from a bombing 

mission grows careless and idly 11 chats11 away the security of an airbase. 

tbes the enemy take advantage of this opportunity'? Here is an ext1·act 

from a report on the resulting enemy raid: 

11 Airbase suffered surprise bombing. Severe ~~~~--..... ---- loss of life and bombing planes sustained." 

How :important is that vital security elenent called RADIO 

SILEUCE? Like a protective mantle of invisibility it affords a se1mrity 

upon which might depend success or failure of a mission. 

Visualize a tank destroyer battalion moving swiftly into 

position for attack. Radio silence has been ordered. On the left flank 

ot the movement a tank detachment becomes lost in rough and wooded country. 

The tempo of the attack is fast, and the utmost coordination is re·~uired. 

The officer in charge of the detachment tosses his security to the wind 

by sending a call to headquarters for bearings. r.receiving no answer, 

he becomes panicky and calls repeatedly. Uhi=le frantically appealing 

~for help the detachment wanders aimlessly, but not for long. Enemr planes 

are informed by their radio intelligence of the detachment's whereabouts 

and lose no time in eliminating the Shennans. 

Violations such as these are inexcusable. A low degree of 

radio transmission security soon takes a high toll in the loss of ~ 

and equipment. 

Radio, when properly operated, furnishes a quick and valuable 

means o! communication. It is sometimes the only available means of 

eclassifi ed and a roved for release b NSA on 09-30-2013 ursuantto E .0. 1352 
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REF ID: A72341-

RESTRICTE,~ 

communication and is highly essential for control of fast moving operations. Radio is the least secure means of communication because it is 

highly vulnerable to enemy interception. Every time a transmitter is 

placed in operation it nust be assumed that enemy interception takes 

ple.ce. Recognition of this fact alone should make every radio operator 

SECURITY CONSCIOUS . 

.An analytical study of Consolidated Reports from all theaters 

and corruna.nds has .made evident the fact that the training of personnel 

in Transmission Security has not been sufficient to meet the current 

security needs of present-day communication systei.~s. 

Radio intelligence is one of the enemy's best organized means 

of obtaining information concerning our plans, troop dispositions, and 

operations. In order to utilize Transmission Security as an effective 

countermeasure, a high degree of training for all communication personnel is required. This training must be continuous in order that personnel will be well informed on current procedure and alert to 11 leaks" provided by deviations from prescribed procedure. 

The following outline is a suggested training course on Radio 

T.ransmission Security. Since the reference material available is limited, 

it is suggested that the instructor use practical da~onstratio~s as much 

as possible. Suggestions as to how practical demonstrations may be 

carried out are listed at the end of the course outline. The instructor 

will deterr.:dne the type of demonstrations on the basis of equipment 

available. 

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COURSE Radio Transmission Secur~ TOTAL HOURS 1\]..LOTTED _ 11 rtiiSTRIBTED 
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COURSE Radio Trcnsmission Security RESTRIGTt.~ 

TOTAL HOURS ALLarTED _JJ_ 

SUBJECT 

Viola- 1. 

tions 

and Their 2. 

Results. 

SCOPE 

b. To enforce security 

rules. 

Violations listed. 

Dangers of violations 

illustrated. 

1. Emphasis on iJli>o:rt.ance of 

I 

TEXT 

REFERENCE 

I FM 24-5 

! Paragraph 118 

I 

I 

! TB SIG 2 

Conclusion Radio Transmission Security. TB SIG 2 

2. Review of all material 

given in course. 

iE-Examin- I Examination on all material 

ation 1 studied in course. 

I 

A.1.1 references 

i listed 

I 

!iETHOD 

P RESE:t-JT .\TION 

Lecture 

Demonstration 

Lecture 

Exar.dnation 

TOTAL 

HOURS 

3 1/2 

1/~ 

1 

*Sample examination forms are available and upon request will be furniflhed in 

the desired amounts by the Chief Signal Officer. 

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SUGGESTIONS FOR DEUONSTRATIONS \f-\1\\\~\t.u 

Suggestion 1 

Set up at different points in the classroom two radioteleg;raph 

sets. Select at random from the class two operators, each of whom ~;hould 

be given a batch of dummy messages and a schedule, with 1.10 instructions 

other than to send the traffic. Silence must be observed in the cl,tssroom so that students may hear the transmissions. As the messages are 

sent bacl~ and forth, violations are likely to occur. The members o.r the 

class shou.ld be instructed to take notes on the transmissions, part Leularly observing any deviations from prescribed procedure and any violations in security. rvben all the messages have been sent, a class 

discussion should be held to criticize the methods of the operators. 

The instructor should then discuss with the class the serious consequences 

' that would have resulted from the violations had the transmissions occurred 

in actual tactical operations. In this way the students are impressed with 

the fact that violations frequently occur and that operators shoulc be 

constantly on the alert to avoid discrepancies in procedure and security. 

Suggestion 2 

Set up one radio telegraph set screened from view of the class, 

with a loud-speaker to amplify sounds of code. Appoint three studtmts, 

A, B, and' C, to act as radiotelegraph operators. One operator itd.l:_ be 

instructed to manifest peculiarities in sending. The other two wi~~l be 

instructed to transr.lit rhythr.iically and uniformly in order to emph."-size 

the difficulty of recognizing an operator with a 11.mechanical fist. ' 

The class will be informed that each operator will send the same message 

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REF ID:A7234. 

containing letters which, if transmitted ca.relessly1 w·ould cause confusion, A transmitting first, B second, and C third. The students will 

listen attentively to each operator and note any peculiarities in Jransmitting habits. 'rhen the class will be informed that the three op1:lrators 

will repeat the message, but in a different order. The operators ·"lil.l 

be instructed to transmit in a different order, i.e., B mi.ght tran 3rni t 

first, C second, and A third. The members of the class will then attempt 

to identify each of the operators. Thus it will be illustrated th~t the 

operator with characteristic transmitting habits is easily recognized and 

may jeopardize the safety of his entire unit. 

Suggestion 3 

In one room, set up a radio net 't•rith a net control station and 

four subordinate stations. In another room, out of earshot of the radio 

net, set up an intercept station. Stucents should be assigned as follows: 

One to the net control station. 

One to each of the subordinate stations. 

Two to the intercept station. 

The remaining members of the class v·d .. 11 be divided into two sections, 

each section to observe the operations in both the radio net room and the 

intercept room for a specified period of time. The radio net is e.i~en 

dummy traffic and schedules, with instructions for the operators cf two 

subordinate stations to follow prescribed procedure, i.e., report into 

the net control station in correct order, authenticate when net ie1 opened, 

e~c., while the other two stations are instructed to deviate somevrhat 

from prescribed procedure. The intercept station will be instructed to 

intercept all traffic emanating from the radio net. Observers wiJl note 

R£SlR18lED 

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discrepancies in sending and receiving, and the valuable info~ion which enerzy intercept stations can obtain from such discrepancies E.s 

the folloi;.d.ng: breaking radio silence when not authorized, transnritting 

unnecessarily or excessively, sending in a controlled net without .r,•ermiss:i.on. This c:lemonstration provides good practice for radio operi:.tors, 

is a practical oeans of illustrating all types of violations, and fiho\VS 

the necessity for Army monitoring stations. 

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