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REF ID:A71866 

TB SiG 2 

WAR DEPARTMENT TECHNICAL BULLETIN 

THINK NEXT TIME 

War Department, Washb1g•oo 2G, D. C., Hi Deeember 1943 

INTRODUCTION. 

THESE ARE NOT JUSt STORIES-the factual incidents 

i-elated herein were taken in substance from data furnished 

by men in army communication units ancl illustrate a few 

of the vfolations of Transmission Security occurring daily. 

Attendant results from these breaches of security, or "leaks," 

are given in some cases; in others, the story is terminated on 

the note of "'hat might have happened. 

To an enemy staff of traffic analysti;. every breach of radio 

procedure bears a telling significunce. Special attention is 

gi>en to each violation, glnring in nature or otherwise. It 1loes 

not matter ·whether the violation tells a revealing story; the 

information imparted may be infinitesimal, but its "strawweight'' may break a communication system locally. It is 

wishful thinking to assume that some casualties, some delays, 

and some ab!::ences of the element of surprise are not directly 

attributable to an alert enemy organization making prompt 

use of informntion furnished through "leaks" provided by 

deviations from prescribed radio procedure. 

RUTRICTED 

eclassified and a roved for release b NSA on 09-18-2013 
REF ID:A71866 

The Admiral Ordered Continued Radio Sllenee. 

Here is a story of General Clark's headquarters ship, taken 

from a stirring account of the Salerno invasion, which portrays A •' 

fully what major issues hinge on the principles of Transmission • 

Security. , . <!T , .... n tlia'" n-m~-~ Snt•,,•dn-.. ... :ftcrnoon thi>. A111rnn',q rndio .i.-'tl,-IJCI v: II .U.&L-.1 .1..1.Lb L• w.a. U.J Li. ,, "- "' ~ 

room reported the interception of an important enemy message. 

Many enemy messages were intercepted that afternoon. 

"But this one message was too pointed for comfort. It was a 

pinpoint location of the headq:uart£rs ship, together with an order 

to sink her at any cost.. 

"Admiral Hewitt decided to move the A.neon from the Salerno 

area. At dusk the ship heaved anchor, and, escorted by two destroyers, sailed out to sea. Strict radio silence was ordered. 

Under a full moon the ship moved out of the battJ.e area. Most 

of us turned in for the first good sleep in 4 nip;hts. 

"At 3: 30 a. m. the alarm bells clanged. General quarters! A 

wave of uneasiness swept the ship. For the first time since the 

expedition started we were without the ack-ack protection of big ~ · 

naval units. Our location was a secret even from our own fighter 

cover. 

"Up on deck all was onrlnously quiet. Gunners were at their 

posts, the hum.an ammunition cha.in ~as in positio~; but there. was 

no order to fire. A slight sea haze diffused the bright moonlight. 

We could hear, faintly, the drone of planes. 

"Down in the wardroom a tense conference was being held. The 

ship's detecting apparatus had a grim story to re~ee..l: bomb~rs 

on our port side, bombers on our starboard, all w1thm a 6-nnle 

r12dius, searching the seas for the A neon. 

"Should we break radio silence to ask for air help~ Or should 

we sit tight and quiet~ Admiral Hewitt ·vas awakened. He 

ordered continued radio silence. 

"For an hour the crews stood by their guns. We moved nervously about the deck pondering the Admiral's grand g~ble. The 

drone of pfo.ne motors grew louder, tben receded; revived, a~d 

finally was heard no more. The sea haze hnd saved us from certam 

destruction. 

"In the morninO' we were back in Salerno Bay. The armada 

was intact. The b~idgehead's first landing field was in operation. A • 

Our fighters were thick over the the area. The luftw1dte had • 

:failed. '

1 ~ (1"printecZ from North American Newspaper . .!UUance) 

2 

Convoy Delayed. 

This glaring violation of Transmission Security happened 

shortly after the outbreak o:f the war. 

A flight of B-25's was assigned to patrol duty on the West Coast. 

Orders read to be on the alert for submarines and to aid in convoying ships. The SOI required a report, upon return of the 

flight, of the position of a certain convoy, the number of ships, -

etc. 

The flight lender flighted the convoy. Not having r~ad th'.C' instructions in the SOI, he reported the position Qf the convoy, 

giving the course, number of ships, etc., in clear language by C. W. 

transmission. 

For its own safety, the c?nvoy was immediately ordered into 

the nearest port. The sailing was delayed for a period of 10 

day~and who can evaluate the LOSS OF THOSE 10 DAYS! 

Bad llaltit. 

There is :o,o such thing as an inconsequential radio transmission. Messages sent in the clear can produce repercussions which 

dim the reverberations of falling bombs. 

A British medical unit in the Sollum area of Egypt formed the 

habit of sending casualty lists in the clear, giving the arm of the 

service of the dead and injured: "Rifleman Adah Singh, killed at 

Gizah; Artillerist Arthur G. Smith, injured at Halfaya Pass." 

Given enough volume of this traffic, the Germans were able to 

locate and identify all the major British units in that sector. 

If wire had been available, this administrative traffic should 

have been sent by telegraph. Wire lacking, a courier should 

have carried the lists. If radio had to be used, the traffic should 

have been encoded. 

Tho enemy is often furniRhed VITAL INFORMATION BY 

PLAIN TEXT TRANSMISSIONS. 

Testing Tipped Them Off. 

Radio silence is more than golden to men who observe it strictly. 

To those who don't--

A division moving up into the combat .zone in North Africa 

failed to observe absolute radio silence, and permitted its radio 

stations to send premature test messages in their new positions. 

Captured Italian intelligence reports later revealed that the enemy had intercepted the test transmissions and deduced that a 

new division was moving up. 

DON'T BREAK RADIO SILENCE until ordered to do- so by 

competent authority. 

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"Good News" for Japs. REF ID:A71866 

.AN ADVANCED .ALASKA BASE, Aprii 20.-An Army coionel tells this one : 

"One of my 'fist fakers' (a telegrapher who can imitate another's touch) who knows Japanese practiced for months to imitate 

the 'fii;t' of a Domei news radio operator who relays daily news 

to the Kiska garrison. 0 

"One evening, as the Domei sender was almost throngh tapping 

out the 'good' news from Tokio to the Rat Island defenders, we 

jammed the program bo t..hat. :iGl:lka Jiu noL hear his i;ign u.IT. 

"Alter this.'jam session' our 'fist faker,' imitating the Tokio 

man's every sending peculiarity, cut in: 

"'DomPi nrwR deeply regrets that Admiral Yamn.moto is disrreditecl in imperial circles because he has Jost too many valuable 

ships. The defeat of our naval forces at Coral Sea, l\fidway, the 

Solomons, and now our 22-ship convoy to New Guinea has saddened the imperial household.' 

"Next our operator sent: 'Due to the lack o:f critical materials, 

basPbaHs in Japan·hnve been reclured to t.he size of goli baHs, 

golf balls to the size of peas, and there are no more peas so we do 

not play golf any more. Thank you, Kiska, that is all.' 

"The Kiska operator, in precise Morse, acknowled~ed: 'Thank 

you, Domei. :for the excellent news. This is radio Kiska signing 

off. Good night.'" 

(Reprinted from Associatea Press) 

Intercepted Clue. 

Because of little consideration for the element of security, and 

some ingenious map-plott.ing by an alert enemy, serious obstacles 

were encountered by the British. 

An attack on H:al:faya Pass was planned by the British. Before 

moving their bases, the British opened radio nets at advanced 

points. With this clue to act upon, German and Italian intercept 

platoons were able to anticipate the disposition of the British 

troops-before they arrived at the front. 

Failure to observe Transmission Security measures makes 

VITAL, I~ORMATION available to the enemy. 

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For Omeial Use Only. 

Numerous infractions of the proper use of radio reflect extreme 

foolhardiness on the part of some operators. Such is this case. 

In February 1942, a radio operator in Charleston, S. C., transmitted the :following message in the clear, "German Submarines 

Sighted in Charleston Harbor." This adolescent trick aroused 

high authorities, and immediate steps were taken to check the 

authenticity of the transmission. 

The moral in this minor incident is th~t our communication 

facilities nre for OFFICIAL USE ONLY and should at no time 

be used for the transmission of foolish traffic or personal messages. 

The Ei!-emy Was Also Willing. 

In this story a radio operator actually talked with the enemy, 

and raised his own colonel out of bed. 

· Apparently the radio operator had for some time harbored a 

desire to "chat" with the enemy. Late one night while scanning 

the bands he picked up an enemy station and established eontact. 

The enemy was also willing to chat, so back and forth via C. W. 

flowed a stream of conversation-until the radio operator realized 

with a start that he was committing a very serious breach of Army 

discipli11e, as well as radio di8cipline. 

Without discontinuing the conversation he dispatched a message to the colonel, who roused himself in all haste to notify G-2. 

Direction finders were put on the enemy signal and the location 

was spotted. 

Isn't it logical to suppose that the enemy SPOTTED OUR 

STATION¥ 

Outeome of Individualism. 

Occasionally a radio' operator finds in the temporary absence 

of normal restrictions an opportunity to indulge an old, lax habit 

of batting the breeze. This story is an instance. 

When our :forces first began establishing outposts on islandc; 

in the South Pacific, the radio operations were taken over by 

skeleton crews who developed small dynasties. Radio procedure 

was more or less what the men themselves established, and it was 

common practice to bat the breeze, or transmit in the clear. 

Staff Sergeant X, an operator with a speed of 45 to 50 words 

per minute, was the head o:f a dynaRty with an unbroken record 

for no services on messages transmitted. He held undisputed 

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REF.ID:A71866 

sway until after the battle of the Coral Sea. Then followed ii.ii 

increase in personnel and a heavier volume of traffic. 

Very little time elapsed until reminders in the form of quotations from Army Regulations were issued pertaining to transmission security violations, especially sending in the clear. 

Sta:ff Sergeant X was resentful oi interference-even of Army l1i 

Regulations. After a month of asserting his belligerence and \~) repeated warnings, he was demoted to buck sergeant. Another 

month passed with no chanire in his attitude. 'I'he outcome of 

his continued individualism was a court martial. He was reduced to the rank of private and relieved. 

A fast radio operator is still NOT A GOOD OPERATOR 

unless he .follows prescribed procedui·e .. 

So Mueb Confusion. 

The demoralizing situation related below is an interesting example of radio deception. If the net-control station had followed 

the rules of Transmission Security, it would not have happened. 

During maneuvers, the artillery in a Blue division dropped the 

use of authenticators. The radio operator of a Red division 

passed himself off as the Blue net-control station. He received 

locations of units, plans of fire, nnd future movements; he directed 

fire into an empty field and along an unoccupied ridge; he persua.ded tl1e receiving operator to ignore the frantic calls of the 

real net-control station, and finally created so much confusion 

and mutual distrust among Blue stations that radio communications broke down completely. 

Think of the disaster that would have resulted from a similar 

situation in combat l 

The Germans Did Something About It. 

Among the violations of transmission security encountered 

daily is the ever-frequent case of sending important information 

in the clear. Take this ex11mple: 

In the early days of the Libyan campaign, two officers were on 

the air talking about the difficulty of closing the 3-mile gap existing between ti\eir lines. 

"I haven't the equipment," -one commented. 

"Well, I can't do anything about it," the other replied. 

Not far distant a German intercept operator hastily sought 

contact with his superior offi<ltlr. This vital bit of information 

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was quickly assimilated by enemy intelligence, and before the 

end of the day the Germans did something about it. 

Radio is a direc.-t link to the enemy. 

I \Vas Not Supposed to Comply. 

The following incident illustrates a violation of rndio-net pro- • 

cedure as told by a station operator. 

"DR;; \HI.::. the m~t-control i:.1.11.tion oi an artillery ueL ii1 the 

Hawaiian Islands. When one, of the operators, identifiable by 

his 'charncteristic fist,' remained continually off the air. it was 

apparent that he had been transferred elsewhere. Sure enoughin a few days I received a call, transmitted by the 'telltale fist,' 

from a neighboring island. He was unable to establish communication with UHa in our net, and wanted me to let UR3 know that 

UR3-7 was calling. 

"I went ahea<l and gave UR3 a call and, shortly 11.fter, UR3 a:nd 

~3-7 established communication and began exchanging greetmgs and personal problems. This was obviously a violation of 

transmi~sion security but as I was not a net-control station, I stood 

by and listened. 

''The following day I learned that a radio intelligence operator 

had copied my transmission to the unauthorized station UR3-7 and 

also UR3-7's transmission to UR3. 

"UR3-7 made up his own call sign to call a personal friend at 

UR3. He included his new post in his trani:;mission, thus releasing 

military infonnation. UR3-7 was not supposed to be working 

on that :frequency, as he held up messages .from other stations 

authorized to operate in the net. I was NOT SUPPOSED to 

comply with UH3-7's request before making u C'hallen(J'e and 

receiving a satisfuctory answer. The call sign UU3-7 was foreign 

and NOT in the SOI issued me." 

1J-Boats Eseaped. 

This significant story is told by an NCO in charire of an aircraft • • b 

warnmg stat10n on the coast of South America. 

"In the latter part of 1941 it was common knowledge that 

enemy submarines \Vere operating in South Amecican waters. 

From our recently established location, occasional observances of 

submarines, presumably German, were reported. 

"We had been operating at this location for about 6 months 

when war was declared. Immediately, the su_bmarine activity 

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REF ID:A71866 

became more noticeable and several reports on enemy submarines 

were sent by radio. Through carelessness, Rome of these reports 

were sent in the clear . . . and without fail, the reported submarine would leave the vicinity, having ample time to do so, as 

the nearest troops were 2 hours flight away." 

Don't show your hand by SENDING IN THE CLEAR I -

....... ~y ~t&!"!". 

Here is a story apparently inRignificant-and yet the actions 

of one man failing to do his job in a remote section of the AlaRkan 

Territory could, and probn.bly did, impart to ihe enemy a fair 

idea of the use of our procedure signals. 

This man, a radio operator, was on duty at his post handling 

a mere trickle of traffic. To lessen the tedium and amuse himself, 

he began transmitting a "breezy story," punctuating it with 

regular procedure signals. During that same period, an intercept 

operator, policing the bands, tlmed him in and discovered this 

obvious violation of transmission security. Our operator had 

picked up the offender-BUT SO HAD THE ENEMY! And 

the enemy also had pirked up a fair idea of how our procedure 

signals fit into a message. 

Send Over Some Beef. 

Here is an example of a striking violation which occurred in ihe· 

Asiatic Theater. 

Our forces were in an extended position, and ihe proximity to 

the filtem.y necessitated the establishment of several outposts. One 

of these was to be an island outpost about 10 or 12 miles distant 

from headquarters. To this point were sent radio operators to set 

up a station. 

Then, for approximately a week, came calm in the clear, such as: 

"Send over some beef, I nm ham happy"; "'We're all out of water, 

get some over here"; and other similar transmissions. 

The enemy, by fo.,tl:'ning in for a few days, could have determined the number of men on the h;land and the tactical disposition-AND MOST Lll{ELY DID. 

Oddity of the War. 

If there are any deubts existing as to the amount of intelligence 

gleaned by the enemy from varied sources, here is a story which 

should quickly dispel any such illusions. 

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A TWA plane pilot heard a strange radio call one day in midAtlantic. A crisp, clear voice in English advised the piJot that he 

was using the wrong code o.f the day. And he was! The voice 

id~tified itself as belonging to a German submarine commander. 

Somehow, some\vhere, there had been one leak or several in our 

commllllications. Make sure that such leaks do not result from 

violations of transmission security . 

qAC. 

This incident has to do wiih IMPROPER RADIO PROCEDURE. From this story ii can be seen that serious consequences 

may attend those who fail to observe it. 

About 1 yeru: ago, at Miami, Fla., a plane wns sent out on an antisubmiirine patrol, using special equipment. During the course of 

the flight an important part of this equipment became inoperative. 

The pilot instructed the radio operator to send a message back to 

the air base stating they were returning because the --ivas out 

of order. 

If the correct procedure signal had been used, with no mention 

of the faulty equipment, the transmission would have been in 

order. Instead ihe message was sent in the clear. When tlte ship 

landed there was an escort of M. P.'s waiting. Both the pilot and 

the radio operator were court-martialed. 

This leak was VITAL. Until then \Ve had every reason to believe that the enemy did not know this particular equipment was 

being used in antisubmarine warfare in that locality. · 

1'Ilssion Not Aeeompllshed. 

Incidents that stress the hazards of SENDING IN THE 

CLEAR cannot be recounted too frequently. 

A formation of B-25's iook off somewhere in Tunisia during the 

early part of the N orih African campaign. Swiftly they climbed, 

and soon they were half wuy to the designated objective. Then 

... a message was received from their air base instructing the 

flight leader to abandon the assigned target and proceed to :mother area. The information, including the name of the new target, was transmitted in the clear. 

When the formation approached the new objective a superior 

number of enemy planes intercepted the flight. The mission was 

not accomplished, and the degree of carelessness took a corresponding toll in men and planes. 

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Disastrous results from transmissionM-&'ieol.R iJh 7J §ip 6 

clear cannot be evaluated. • 

Enemy Notified. 

Frequently, information is impurted to the enemy by a.n un- 9 

trained radio operator. The following incident occurred in one 

outfit. and probably has in numerous others. 

The scene of il1is short story is a combat zone where violatioub 

of transmission security may be measured quickly in terms of 

casualties. Pfc Y was an untrained radio operator who unwittingly notified the enemy as well as the stationi:: within his net of 

the call signs to be used the following day, by first identi:rying 

each one with the current call sign. 

Obviously, the call signs were compromised even before they had 

been put to use. . 

T.raflie Was Delayed. 

Prompt distribution of SOI's within a net is always an important fact.or, ltS this story clearly shows. • 

In the combat zone where this particular net was in opere.tion 

transportation was at times slow and very uncertain. The on1; 

means of transportation fo this area were by water and air: 

SOI's were made up by headquarters in the rear echelon, about 

1,500 miles dist.ant. The majority of stat.ions were so removed 

f1·om headquarters that from 1 to 3 days', travel by air was neces-

~ary to traverse the distances. Call signs were changed periodl(!ally and frequently, but not always did distribution of SOI's 

include the forward stations. 

Personnel of the rear echelon station, not realizing the situation, would, on the appointed hour, change over to the new call 

signs and refuse to ans~·er the old ones. 

This caused considerable delay in handling traffic. 

It is well to re.member that because of slow tra:ftic-:MESSAGES 

THAT ARRIVED TOO LA.TE-battles have been lost. 

Was the Enemy Listenln.g1 

Radio chatting is always music to the ever-listening ears of the 

enemy. Here is another story wherein the desire to talk paid poor 

dividends. 

18 

Somewhere in North Africa, a pilot was returning from a reconnaissance mission sucooss:fully completed. It might ha.ve been 

elation over a job well done or a general sense of relaxation which 

caused the officer to indulge in chatting. 

During the ensuing chat this officer mentioned that a large 

formation of aircraft had landed at a certain air base. Was the 

enemy listening! Obviously he was, because in a few short hours 

the air base was bombed and almost totally de.c;troyed. 

No matter how strong the temptation-DON'T CHA.T 1 

Ball Sessions. 

Too often the security of a post or station is jeopardized by 

LAXNESS IN MONITORING the net. The following situation 

could have been quickly corrected. 

The net-control station was located at a post that was, we had 

reason to believe, unknown to the enemy. As this net linked the 

post with outposts in the Parific and Bering Sea, the maintenance 

of circuit discipline was highly important. 

The staff sergeant in charge of the station was an excellent and 

highly trustworthy operf!,tor. As time passed, with only routine 

messages constituting the traffic, he grew lax, and decided that 

conversation with one of the other operators would not be 

harmful. 

At 1145 und again at 1200 of each day, stations would be coordinated bv the NOS. 

The inte~ening time was used by the staff sergeant for his "bull 

sessions." 

This continued for about 2 weeks until, by aha.nee, the nearest 

.A. WS station happened to be listening on the frequency used by 

this NCS, and heard this transmission : "Yes, Larry left with 

supplies for the OP at Ybor on the Sta:rk yesterday • . ." etc. The 

sta.ff sergeant was seveooly disciplined. 

M 0 N I T 0 R I N G is a necessary function of Tranmission 

Security. 

SDlilpeeted Espionage. 

(,'hatting always helps the enemy in one way or another. In 

this instance it was a means of distracting for several nights the 

functions of a "spotter" net. 

The incident took place overseas in -an aircraft-spotter net 

charged with monitoring both friendly nets and enemy spy stations, and with goniometric activities. 

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REF ID:A71866 

On goniometric operations it was necessary to use radio for 

communication to Control as the base lines were from 350 to 500 

miles distant. Selecting frequencies for 24-hour communication, with available equipment, presented something of a problem. It finally became necessary to use frequencies close to other • 

radio channels o.f our forces. 

In a nearby outpost. net there were two radio operators in the 

habit of passing the night hours by chatting. To escape detec-

, tion they would shift their frequency. One night, this shi.ft of 

frequency landed them on the channel of the aircraft-spotter neck. 

Immediately the spotter net grew alert. Could these be new 

espionage stations using informal conversation to transmit ship 

movements to German submarines W Bearings were taken for 

several nights to determine the locations accurately. An investigation brought the solution-the two radio operators were uncovered as the suspected "espionage'' stations. 

CHATTING, like crime, NEVER PAYS. 

Radio Operator Talks. 

Transmission security cannot be effectively obtained without 

a STRICT PERSON.AL CENSORSHIP on the part of the operating personnel. .A report recently received in Washington 

clearly illustrates this. 

The report read: "Captain --and I were notified in confidence 

that we were to take a plane to Erehwon and stand by for passengers. We were notified we were to leave -- Field secretly. 

Within 30 minutes the rest o.f the crew reported to us and said 

that they had heard from a radio operator that we were to leave 

in a few hours. We were soon besieged with requests from .Army 

and other personnel who wanted to ride with us." 

In this particular instance, proper action was taken immediately and no damage was done. 

PresDJDahly Bona Fide Orders. 

B.adic dcccpticn fa irc.que.n:ly pra.:.ticed by tlie euemy in an 

attempt to gain an objective. This story should serve as a lesson 

in the importance of AUTHENTICATION. Here is shown how 

failure to authenticate results in an effortless victory for the 

enemy. 

During the German campaign against Norway, plans were made 

by the invader for an easy occupation of Bergen. On 9 .April 

1940 the Germans sailed troop and supply ships, along with 

12 

escorting cruisers and destroyers, into the harbor. Several hours 

before this task force arrived, the N orwcgian officers at Bergen 

had received presumably bona fide orders by radio to abandon the 

fort. Since the Norwegians made no effort to authenticate these 

messages, they :Cell easy prey to the Germans' ruse. 

REMEMBER-FOLLOW AUTHENTICATION IYSTRUCTIONS TO THE LETTER. 

CONCLUSION. 

TRANSMISSION SECURITY is an effective countermeasure 

against enemy e:ll'orts to obtain intelligence by an analysis of our 

transmitisions. 

I:C the serious consequences of violating Transmission Security 

are understood by communication personnel, prescribed radio procedure will be more closely followed. 

Maintenance of circuit discipline is dependent upon close supervision by the net-control station, the agency responsible for its 

enforcement. 

Authentication is an effective means of defense against forms 

of radio deception practiced by the enemy. 

ALL VIOLATIONS .ARE DANGEROUS. The foregomg 

stories are intended to provide communication personnel with the 

form and identity of certain frequent violations. 

DON'T ENDANGER YOUR UNIT byTranamitting in tlie c"lea:r without proper authorization. 

Oha,tting. 

Bre<iking radio silence. 

Sending wnauth<Yrized communications. 

Using improper radio procedure. 

rA. G. 300.a (27 Nov 43).1 

BY ORDER OF TIIE SECRE'l'ARY OF w AR: 

0FFICIAJ.: 

J. A. ULIO. 

Major General, 

G. C. MARSHALL, 

Ohief of Staff. 

Tlte Adjutant General,. 

DISTRIBUTION: 

13 U S GiOYEllHMENT PRIHTllHI OFFICE1 IHJ