547 SIGNAL TROOP AND THE ARMY SECURITY AGENCY
Phil Rutherford Ph.D 2020
547 Signal Troop and the American Security Agency
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547 Signal Troop and the American Security Agency
547 Signal Troop and the Army Security Agency Phil Rutherford Ph.D Copyright © 2020 by Phil Rutherford. All Rights Reserved.
No part of this publication may be reproduced, distributed or transmitted in any form or by any means, including photocopying, recording or other electronic or mechanical methods, or by information storage and retrieval system without prior written permission of the author, except in the case of reasonable quotations in critical reviews, for study purposes or other non-commercial uses permitted by copyright law. The information contained in this publication has been drawn from publicly available sources, including declassified records and contemporary literature. The ideas and processes described in this book are drawn from interviews and personal recollections of members of 547 Signal Troop and the allies with whom the Australians closely worked during the war, and may vary from the experiences or recollections of others. The author is not an expert in the equipment or processes described in this publication, therefore any discussions or descriptions of the equipment or processes have been drawn from the available literature. Wherever possible secondary sources have been reviewed in order to clarify the details described in this publication and, where available, sources have been cited. Owners of photographs or illustrations used in this publication who have not been acknowledged are requested to contact the author in order that such acknowledgement may be properly made.
P D Rutherford Ph.D [email protected]
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547 Signal Troop and the American Security Agency
Table of Contents FOREWORD ...... 7 INTRODUCTION ...... 9 The road blocks ...... 10 PART ONE - COMMAND AND CONTROL ...... 12 A question of ownership ...... 13 The USASA ...... 14 Off to war ...... 15 Command and control in Vietnam ...... 16 Under control of the US forces ...... 18 The Troop increases its value ...... 20 The birth of the US military cryptography ...... 24 “Chut, J’ecoute” – US intercept during World War One ...... 25 “Gentlemen do not read each other’s mail!” ...... 27 PART THREE - THE ARMY SECURITY AGENCY GOES TO WAR ...... 29 The ASA grows ...... 31 509th Radio Research Group ...... 33 303rd Radio Research Battalion ...... 35 COLLECTION MANAGEMENT AUTHORITIES ...... 37 175th Radio Research Company ...... 38 DIRECT SUPPORT UNITS ...... 41 ARDF ...... 43 The ASA takes to the skies ...... 44 The US Air Force joins the fight ...... 45 From experiment to operation ...... 46 ASA versus USAFSS ...... 47 PART FOUR – ASA AND THE AUSTRALIAN TASK FORCE ...... 50 547 Sig Tp arrives in country ...... 50 DSU to the Task Force ...... 52 Dodo ...... 52 SIGINT and the battle at Long Tan ...... 60 Side-stepping official channels ...... 62 Operation TOLEDO ...... 63
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547 Signal Troop and the American Security Agency
Special Forces pick up the DF task ...... 66 D445 ...... 68 DET 2, 175TH RR COY – NUI DAT ...... 69 Det 2 joins the Australians ...... 69 A death in the family ...... 73 Det 2 moves again ...... 74 PART FIVE – POSTCRIPT ...... 76 Chasing the Chau Duc ...... 79 Speaking of recognition ...... 81 GLOSSARY ...... 85 REFERENCES ...... 89
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547 Signal Troop and the American Security Agency
FOREWORD
‘Not only do you not exist, you never will have existed. You will remain for always unknown and unacknowledged. There will be no awards, no glory. There will be no medals for this unit.’1
This paper concerns an aspect of military history known to only a very few inside the Australian Defence Forces. In fact, the full story is known to an even narrower tranche of those whose security clearances were sufficiently high to give them access to the world of signals intelligence during the Vietnam War, including the soldiers who lived this story. Even the families of soldiers who served in this unit were for many decades unaware of the true nature of their actions. Little was, and still is, known about the highly secretive 547 Signal Troop. It was unique amongst both Australian and allied forces because it belonged to neither the Australian nor the American higher commands, but at the same time it was under direct control of both. And while the Troop gave continuous support to both the 1st Australian Task Force (1 ATF) and the Second Field Force—Vietnam (II FFV) it was never listed in the order of battle for either. Throughout most of the five and a half years the Troop was in Vietnam, the military, and the government, did their best to deny its existence, the success of which was borne out by a report prepared for the Federal Government in 2015 in which the Australian Army is quoted as finding little praiseworthy in the Troop’s actions. But the Troop did exist, as proven by the high praise and commendations received from both Australian and American commanders during and after the war. The authority upon which the Troop was ordered to Vietnam came from an agreement between the intelligence services of the Australian and US governments. This agreement stated that the Troop was to be employed ‘in conjunction with the US ASA2 organisation (in) Communication Intelligence (COMINT) operations in South Vietnam’.3 These orders clearly stated that it was to be known as the ‘AMF Direct Support Unit (DSU) of 1 ATF’.4 Their work was to be so critical to the success of the allied forces that, according to the agreement, soldiers deployed to this Troop were not to be employed on ‘hazardous operations where (their) capture or interrogation could be a substantial risk to the security of (communications intelligence)’.5 However, as the men posted to this Troop
1 Anon. Quoted in Hillier, J. (1993) No Medals in this Unit. Published by author. 2 The United States Army Security Agency. 3 AHQ (DMI) Instruction No. 1/66 COMINT Support for 1 ATF Vietnam. Paragraph 1. 4 Op cit. Paragraph 3. B. The term DSU was only used by the US Army Security Agency for those groups forming part of the American signals intelligence network. 5 Op cit. Paragraph 20.
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547 Signal Troop and the American Security Agency found out, the purpose of their deployment could not be achieved unless this directive was ignored. The men of 547 Sig Tp were armed and trained just as any other soldier. They undertook battle fitness training at Canungra and were totally undistinguishable from other soldiers serving in Vietnam, but they never fired a weapon in anger. They had no need to. Their actions against the enemy were, as described by an American historian, like ‘Spartans in Darkness’, fighting a counter-insurgency war from within the shadows. Their weapon was the ability to take one of the enemy’s greatest strengths, their skill at hiding deep in the mountains and the jungles, and turn them into weaknesses. A popular saying during the war was that “We own the day, Charlie6 owns the night.” The VC may have ‘owned’ the night, but the men at 547 Sig Tp knew how to find them. On many occasions members of the Troop went outside the safety and security of the Australian and American bases in light, unarmed aircraft, or in twos and threes to locate the enemy positions. In order to carry out these tasks they quite often had to be separated from the protective shield of the infantry and armoured personnel carriers dispatched to watch over them. Some even had to quickly learn how to patrol with our special forces in order to more effectively complete their mission. From the day the Troop arrived in Vietnam to the day it departed, the men were in continuous contact with the enemy forces, following their movements and analysing their intentions in order to guide friendly ground and air combat forces against them. The number of casualties inflicted on the enemy through the actions of this Troop is incalculable, far more than any other unit of the Australian Army. Just as the number of lives they saved through timely warnings of ambushes and attacks by the Viet Cong and North Vietnamese Army. But this is not a history of 547 Signal Troop. The history which, to date, can be written has been more than adequately captured in the extensive work undertaken by Bob Hartley and Barry Hampstead, both former members of the Troop. These works can be found in the online archives of the Australian War Memorial. Instead, this paper concerns the relationship between the Troop and the USASA with whom they were under operational control. The purpose of this paper is to bring to light a previously unknown element of the story of 547 Sig Tp and its relations with its counterpart, the Army Security Agency. Hopefully what this paper has achieved is identify where there are still many stories to be told. Phil Rutherford Ph.D Canberra, Australia August 2020
6 Charlie, as in Victor Charlies – phonetic alphabet for VC or Viet Cong
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547 Signal Troop and the American Security Agency
INTRODUCTION
On 11 June 1969 I arrived at Tan Son Nhut airport in Saigon, South Vietnam, on my way to join 547 Signal Troop (547 Sig Tp) at Nui Dat in the Phuoc Tuy Province. As this was my first overseas deployment I didn’t know what to expect. All I knew was that the Troop provided signals intelligence (SIGINT) support to the 1st Australian Task Force (1 ATF), and my job would be to monitor enemy radio signals in order to identify their location, strength, and future intentions. Prior to arriving in Vietnam I had spent fifteen months with the Army Reserve and two and a half years with the Regular Army, so I was not new to the military. But from the day I arrived every experience was new, from the hustle and bustle of the world’s busiest airport to the Colt M16 Armalite rifle I was issued when I joined the Troop later that day. I had never seen an M16 before, much less fired one, and it took a couple of days before I could be taught how to load and look after it. But it was much longer before I got used to the helicopters that would land day and night within 50 metres of my tent. Because everything was so new I also didn’t think it odd that each day we would be visited by an officer from the United States (US) Army, and the occasional American civilian, who would arrive in a helicopter, spend a couple of hours with our OC (officer commanding the Troop) and his operations staff, and then leave. Nor did I think it strange that every now and then one of our operators would disappear for a week or two and, in his place, would be an American specialist from some place called Long Binh or Bien Hoa. Like other members of the Troop I enjoyed the company of the Americans. Many stayed overnight and joined us in the club for a few drinks and good fellowship. All ranks could be found in our club, even senior officers, but it never crossed my mind that we were doing anything other Australian units were not. It was not until 2015 that I learned why our unit was so different, and why we were so close to the Americans. This revelation came about as a consequence of a hearing by the Defence Honours and Awards Appeals Tribunal (the Tribunal) concerning our unit’s eligibility for the Australian Meritorious Unit Citation. The hearing commenced in 2012 and, despite lasting more than two years, the Tribunal concluded that it had been unable to identify anything that the Troop had done (and, by implication, the men posted to the Troop) that was sufficiently worthy of any recognition. The Tribunal therefore recommended to the government that no action be taken to recognise the Troop for its actions in Vietnam. While the outcome was a disappointment to us all, the Tribunal actually did us a favour by opening a Pandora’s Box of information previously unknown to many of us. Included in this information was the revelation that from the day the first elements of the Troop arrived in Vietnam in 1966 until the day we departed in 1971, we were under operational control of the Americans, under arrangements experienced by no other Australian unit during any conflict up to that time or since.
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This intrigued me such that I began to investigate whether or not other Australian elements were similarly under direct control of the Americans, and how such an arrangement came about. What I hoped to do was unravel the mystery of why the Australian Army knew so little about the Troop and our actions, why it was such a secret then, and why such secrecy continues to this day.
The road blocks My journey was not to be as simple as I had hoped. The first obstacle I came across was the lack of official information readily available about our actions during the war. I found this strange because the Troop was operational in Vietnam longer than any other independent unit of the Royal Australian Signals Corps. 7 There was a wealth of information about other units, but there was very little available in either the National Archives or the records of the Australian War Memorial concerning what we did or why we were there. We also appeared to be the only unit that did not keep a day-to-day War Diary, a mandatory requirement of all units during wartime. Equally as strange was the fact that the Troop is still not shown on a mud map of Australian units in the Vietnam display section of the Memorial, and nor is it listed in the Wikipedia entry concerning the Australian Army Order of Battle in Vietnam. In fact more can be found out about the Troop in the Cryptologic Museum at the National Security Agency (NSA) at Fort Meade in Maryland, USA, than in any public museum in Australia. This has since changed with the expansion of the National Vietnam Veteran’s Museum in Victoria, but despite repeated requests there is little interest from the AWM. The Australian Army records were of no assistance either, as these are very sparse for the period. During the hearings the Tribunal sought these from the Department of Defence, but a representative from the Army History Unit admitted to not being able to find any information about the Troop. A representative of the Defence Directorate of Honours and Awards gave a similar response. Either the search for information carried out by Defence was incredibly sloppy, or there is indeed no record held by Army about the Troop or its role during the war. An official acknowledgement was made concerning the Troop’s existence by the Australian Signals Directorate (ASD – formerly the Defence Signals Directorate) during an in camera interview with the Tribunal, at which time hints were dropped that such details do exist. But, according to ASD, these are and will remain under lock and key despite the growing number of books concerning the war in Vietnam in which the Troop is (finally) gaining recognition. Nevertheless, information about the Troop and its actions is beginning to emerge. The official history of the South East Asian conflicts records the Troop as the source of intelligence critical to Task Force operations, as do recent non-fictional literature about the war in Vietnam. But that is as far as public acknowledgement goes. Little continues to be
7 709 Signal Troop served longer in Vietnam but it became a sub-unit of 145 Signal Squadron.
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547 Signal Troop and the American Security Agency known about how the men of 547 Sig Tp went about searching for the enemy forces, identifying and locating them, and using this information in such a way as to bring them to battle against Australian, American, and South Vietnamese forces. Because of this little is known of the part played by the Troop in the tactical and strategic successes achieved not only by the Australian Task Force, but by all of the allied forces for whom we directly or indirectly provided supported. Aside from the excellent work undertaken over recent years by former members of the Troop, it appears that our presence in Vietnam is still a closely guarded secret. After the Tribunal hearing I therefore set out to learn as much as I could about our deployment and the major US units which had so much impact on our actions. What follows is a description of where and how 547 Sig Tp fitted into the signals intelligence network in Vietnam between its deployment in March 1966 and return to Australia in December 1971.
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547 Signal Troop and the American Security Agency
PART ONE - COMMAND AND CONTROL
At the conclusion of the Tribunal hearing a detailed report was prepared and submitted to the government. Deep within this report was a declassified copy of the Troop’s deployment orders signed in June 1966 by the then Director of Military Intelligence (DMI), Major General (then Colonel) Cedric "Sandy" Pearson, AO, DSO, OBE, MC. These orders showed that while the Troop was deployed under command of the 1stAustralian Task Force (1 ATF), we were also under operational control of an entity called the USASA organisation. The USASA was the United States Army Security Agency, the military arm of the National Security Agency (NSA), an element of the American government responsible for global collection of communications and data intelligence. The ASA no longer exists, but between 1945 and 1976 it was the US Army’s communications intelligence branch with a history dating back to before World War I. A search of the records failed to find an organisation by that name in Vietnam at the time of the Troop’s deployment. This, I found, was not unusual as the secrecy surrounding the deployment of NSA assets to Vietnam meant that the formed units had to have a cover title. In June 1966, just as 547 Sig Tp was arriving in country, the main headquarters for ASA in Vietnam was being retitled as the 509th Army Security Agency Group, later known as the 509th Radio Research Group (509th RR Gp). It was to this formation that the Troop was deployed under operational control. The Troop was not the only Australian Army formation to be under operational control of the US forces. Between 1962 and 1966 two other units were deployed under similar command arrangements: the 1st Battalion, the Royal Australian Regiment (1 RAR) during its first tour when it was under operational control of the 173rd Airborne Brigade (Separate) (173rdAbn Bde), and the Australian Army Training Team—Vietnam (AATTV) which, throughout its existence, was under operational control of the United States Military Assistance Command—Vietnam (USMACV).8
8 A number of RAN and RAAF formations were also deployed under operational control of US forces. This paper will only discuss Army deployments.
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USMACV was the joint service command headquarters responsible for control of all advisory and military assistance efforts in Vietnam. All allied forces were either directly or indirectly under operational control of this group – except 547 Sig Tp. The 509th RR Gp, the unit under whose operational control the Troop was deployed, was actually assigned under command and control of a separate formation altogether – the US Army—Vietnam (USARV). The USARV was the support command controlling all US Army service and logistical units in South Vietnam. As well as the USASA, under the USARV were groups with responsibility for logistics, aviation, signals military police, and so on. This did not affect the way in which the men of the Troop went about their business, but it did make tracing the chain of command a more complex task.
A question of ownership Making it even more difficult to get a clear picture of the Troop’s command arrangements was the question of who ‘owned’ the Troop and the intelligence it gathered. The answer to this question depended on the context, i.e., did it concern national authority over the Troop, command authority, or day-to-day control? ‘Ownership’ of the Troop could be found within each of these. National authority over all Australian forces in Vietnam – Army, RAN and RAAF – was held by the Commander Australian Forces Vietnam (COMAFV). All, that is, except for 547 Sig Tp. National authority over the Troop was held by the Australian Army Headquarters (AHQ) in Canberra, more specifically the DMI. This arrangement came about because national (i.e., Australian) authority over all SIGINT operations throughout Australia and overseas was the Defence Signals Directorate (DSD – now ASD). Retaining this authority was an essential aspect of what was called the Five Eyes agreement, a multi- lateral agreement between Australia, the United Kingdom, Canada, New Zealand and the US, wherein signatories would cooperate in the gathering and sharing of signals intelligence. This meant that the Troop could not be employed in any way without agreement between the Australian and US headquarters’. But, to add further to these complex arrangements, there was little the Troop could do without first clearing it through DMI. The difficulty with these arrangements came to a head when the Troop requested the use of an M577 Armoured Command Vehicle (ACV) in order to deploy to the field in support of Task Force operations. A simple request but one which required multiple levels of approval because, despite the Troop being deployed to Vietnam as part of the 1 ATF order of battle (ORBAT), it was not under the control of the Task Force commander. That it was not a decision the Task Force commander could make demonstrated that, while we were in direct support of the Task Force and could therefore provide whatever support the commander required, we were not ‘owned’ by the Task Force, or
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547 Signal Troop and the American Security Agency even by the Commander Australian Forces Vietnam (COMAFV) who held authority over all other Australian forces in Vietnam. Permission to use an ACV required approval from levels much higher than could be found at the time in Vietnam, not the least because it implied that the Troop would be conducting operations beyond those detailed in its deployment orders. It took lengthy correspondence between the Troop and DMI to finally convince the latter of the importance of having – at least on temporary loan – an ACV in order to safely and securely deploy to the field in support of Task Force operations. An ACV was finally provided, with an appropriately cleared driver, but it was on a shared basis with 104 Signal Squadron and the Task Force intelligence team.
The USASA So far I have only highlighted the command and control of the Troop from the Australian perspective. Australian forces were only in Vietnam at the request of the US Government who delegated command authority over all operations in that country to the Commander in Chief Pacific (CINCPAC). This meant that all US and free world forces in Vietnam were directly subordinate to CINCPAC – except USASA. National control over the ASA was held by the Commanding General USASA (CGUSASA) at Arlington in Virginia which, in turn, was under operational control of the Director NSA (DIRNSA) at Fort Meade in Maryland. Army initially insisted that all cryptologic resources in Vietnam should come under control of MAAG (Military Assistance Advisory Group, the predecessor to MACV), however when the first ASA resources arrived they were placed under operational control of USASA. A compromise was reached between the CGUSASA and the Commander MAAG and it was agreed that further control would be delegated to the latter. This gave MAAG, and then USMACV, a say in how the ASA assets were deployed but ultimate control remained with DIRNSA. With this agreement the NSA became what was described as the wholesaler of communications security (COMSEC, which included signals intelligence) doctrine, codes, instructions and procedures etc, while the Services were the retailers of crypto materials and formulated their own requirements. 9 Because 547 Sig Tp was under operational control of the USASA, for the duration of its deployment to Vietnam the Troop was notionally under control of the DIRNSA as part of the wholesale chain of supply. Exactly how much control NSA had over our operations is not clear, but on at least one occasion we were instructed to cease tentative planning for an intelligence operation against the VC radio communications on direct instructions from the Agency. On another occasion the Troop had in its possession code books captured by Australian forces from a VC regiment, however this lasted less than a day before DIRNSA directed they be delivered to Fort Meade.
9 Anon (1970) Working Against the Tide (COMSEC Monitoring and Analysis). Part One. Cryptologic History Series: Southeast Asia. Page 2.
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In simple terms, despite not being part of the US military, the intelligence product captured by the Troop belonged to USASA who forwarded it to NSA. What was done with the intelligence was a decision for USASA. When appropriate this intelligence would be shared with others, including the Australians. There were many occasions when critical intelligence gained by the Troop needed to be shared with other units but could only be presented if it was declared as coming from the Americans. Because of the perceived need to restrict the number of people who were aware of the Troop’s presence and its tasks, the Task Force commander would receive regular briefings and reports (euphemistically termed Special Agent Reports – SPARS), but the bulk of the intelligence gathered by the Troop was sent to the Americans at Bien Hoa and Long Binh who would then report it back to the Task Force. It was not until 1968 that the Troop commander was officially able to brief the Task Force commander directly on a regular basis. To ensure that such sharing took place a civilian from the DSD was embedded with the USASA forces at Bien Hoa. While this gave the Australian government timely access to critical intelligence concerning the Australian area of operations, it also ensured that the delicate balance was not upset by the actions of the Troop. To fully understand how these arrangements worked I spoke with many US veterans and others within the American intelligence community. I also spoke at length with officers from the US Army Intelligence and Security Command (INSCOM) at Fort Belvoir in Virginia, the National Cryptologic Museum and historians at the National Security Agency (NSA). All confirmed that the Troop was a critical element of the ASA intelligence chain of command and, for operational purposes, the NSA. So, who did the Troop belong to? Was it the Australians or the Americans? It appears from discussions with former officers commanding the Troop that we belonged to many masters. The Australian Army, DSD and the Task Force knew that we did ‘something’, but what was not always very clear. On the other hand, the USASA knew that critical intelligence was being captured, analysed, and the results directed to commanders in the field (including the Australians) but not by whom. It is perhaps because of this the Troop received no recognition from either despite commendations made during and after the war.
Off to war Without access to records concerning discussions between the Australian and US authorities prior to the Troop’s deployment, it can only be assumed that senior commanders within the Australian military and intelligence network agreed to these arrangements. Records which are available show that these arrangements were likely also well known to the Australian military headquarters in Canberra (and to two of the eight Task Force commanders who were, prior to their deployment, Director of Military Intelligence). But, because of the extreme secrecy our presence and our actions, they were not common knowledge outside of the highest intelligence circles in Australia and the USA. Therefore, in the absence of absolute knowledge, myths and rumors will abound. For
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547 Signal Troop and the American Security Agency example, it was often suspected that we were monitoring Australian communications in order to highlight breaches of signals operating procedures and security. We were not (that was the responsibility of our neighbours, 104 Signal Squadron), but denials never seemed to fully allay the suspicions held by others within the Task Force. The true nature of the Troop’s deployment was certainly not well known to the men at Nui Dat. Therefore, in order to explain the full complexity of these control arrangements it is important to also understand how the command and control system worked on the ground during the war.
Command and control in Vietnam In Vietnam the Australian forces came under two lines of command: Firstly, as noted above, was the Australian Forces Vietnam (AFV) providing national command to all Australian forces in Vietnam, including the 1st Australian Task Force (1 ATF), 1st Australian Logistic Support Group (1 ALSG) and the AATTV. The second line was operational control through which operational tasking was directed to subordinate units. Exercising national command meant that the COMAFV, as well as commanding the Army component, held responsibility for administrative and logistical support for all Australian forces in Vietnam. Reporting directly to the Chairman of the Chiefs of Staff Committee (CCSC) in Canberra, COMAFV also negotiated directly with COMUSMACV when it came to the overall employment of Australian troops, on-shore naval forces and aircrews. Operational control, on the other hand, was devolved from an agreement in 1966 between COMUSMACV and the Chief of General Staff (CGS), the highest military authority at the time in Australia. This agreement laid out the arrangements for all Australian forces, noting that while the overall command was vested in the COMAFV, operational command was delegated to the Commander of the US Second Field Force— Vietnam (II FFV). This was the corps level headquarters responsible for command and control of all American and Free World Forces (ie, all forces except the South Vietnamese) in the tactical zone of the 3rd Corps of the Army of the Republic of Vietnam (ARVN), usually referred to as III CTZ (or Military Region – MR – 3). (See Figure 1 below.) Operational control of other units or detachments (presumably including 547 Sig Tp) was to be ‘as agreed between COMAFV and COMUSMACV’.10 Responsibility for day-to-day employment of the Australian forces within III CTZ fell to Commander II FFV. In the case of 1 ATF, this included tasking, assigning objectives and giving the authoritative direction necessary to accomplish the Task Forces’ mission. (See Figure 2 below.) Throughout the war the USMACV retained ‘decisive influence’11 over the actions of all allied forces in Vietnam, therefore 1ATF operations,
10 ‘Military Working Arrangement between Commander, United States Military Assistance Command Vietnam and Chairman, Chiefs of Staff Committee Australia dated 30 November 1967.’ Paragraph 2.g., 11 This is described in Records of the Military Assistance Command Vietnam. Part 1. The War in Vietnam, 1954-1973. MACV Historical Office Documentary Collection. University Publication of America. Page xiii.
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547 Signal Troop and the American Security Agency while relatively independent within the Task Force Area of Responsibility (TAOR), were conducted in support of the overall US mission, as directed by CINCPAC through USMACV and as contained in the agreement between CSCC and COMUSMACV. And while there was a certain amount of flexibility in where and how such operations were conducted in Phuoc Tuy Province, they were always part of the wider strategic plan for III CTZ.
For example, during the so-called Mini-Tet in 1968 the Task Force established Fire Support Patrol Bases Coral and Balmoral 60 kilometres north west of Nui Dat. This deployment was under command of II FFV and was well outside their normal area of operations. This was not the first occasion when the Australian Task Force was deployed by II FFV in support of American operations, and it would not be the last. And nor would it be the last time the Troop would send men to the field in support of the Task Force or US forces.
Figure 1. US command structure – Vietnam. This Figure suggests that USARV was subordinate to USMACV which is incorrect. The commands were separate even though the commander USMACV was also commander USARV. A certain amount of control was also held over the Australian forces through the embassy in Saigon. The Ambassador was the ‘eyes and ears’ of the government on the ground and held responsibility for decisions of political or sensitive nature, including where and how Australian forces were employed. For example, decisions concerning whether or not Australian forces received foreign honours and awards were communicated through the embassy as these often required negotiations with the British government. The Ambassador also kept a very close watch on the actions of the Australian forces and readily communicated these directly to Federal Government ministers. In later years it was not uncommon for the Minister for the
Accessed 15 March 2020 from http://www.lexisnexis.com/documents/academic/upa_cis/3208_RecsMACVPt1.pdf
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Army to respond to a communiqué from the Embassy by placing a call through the Task Force commander.
Under control of the US forces The first port of call for Troop OCs on their arrival in Vietnam was not the COMAFV or the commander of the Task Force. It was the NSA DODSPECREP (US Department of Defence Special Representative) at 509th RR Gp in Saigon. It was here that they received their first briefing on the SIGINT picture and the Troop’s reporting relationships with the USASA, and in particular the 303rd Radio Research Battalion (303rd RR Bn) to which the Troop was assigned. The 303rd RR Bn was one of three major sub-units of 509th RR Gp, Along with 313th RR Bn and 8th Radio Research Field Station (8th RRFS), this unit had responsibility for administration of all signals intelligence units throughout its tactical area of responsibility (III CTZ). The battalion was located at Long Binh in the same military region as the Troop and was therefore in direct control of the Troop’s actions within the wider US intelligence network.
Figure 2. Australian command and control in Vietnam from May 1966 (Adapted from Horner, D (1986) ‘Australian Higher Command in the Vietnam War’. Published by The Strategic and Defence Studies Centre. Australian National University, Canberra.) For operational tasking and higher level analysis of intercepts and other intelligence, the Troop also worked closely with another US formation, the 175th Radio Research Company (175th RR Coy) at Bien Hoa. For this purpose 547 Sig Tp was notionally attached to 175th RR Coy who, although working very closely with 303rd RR Bn and 509th RR Gp, reported directly to USMACV (Figure 3 below). (These units will be discussed in more detail in the coming pages.) Intelligence from all sources (not just SIGINT) was analysed at 175th RR Coy and forwarded to the Special Service Group (SSG) from the USMACV’s 525th Military Intelligence Group (525th MI Gp). The SSG had a detachment – an SSD – at the II FFV
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547 Signal Troop and the American Security Agency headquarters and an officer would liaise on a daily basis with the Troop in order to gain further real time intelligence on intercepts and radio direction finding activities.
Figure 3.Operational command ORBAT for 1 ATF Signals Intelligence operations To further complicate the chain of command, while the Troop’s deployment orders specified that it was to provide direct support to the 1 ATF, it did both indirectly and directly. Indirectly, the main source of intelligence from signals intercepts, including those captured by 547 Sig Tp, came through reports and briefings presented by the SSD liaison officer or through Special Agent Reports detailed on the Task Force records as SPARs. Support to the Task Force therefore originated with the Americans, the task of the Troop being to feed intelligence into the US chain of command in order that it be analysed in line with data gathered from other areas of the intelligence gathering network and fed back to the Australian commander. This indirect avenue of intelligence support may appear complex and time intensive, but it was in accordance with the orders for the Troop’s deployment. When released by the Tribunal it was revealed that the purpose of the Troop’s deployment to Vietnam was to act as a conduit for intelligence gathered by US forces, even though it was clear from the beginning that 547 Sig Tp would be one of the sources of this intelligence. As a result, for most of its time in Vietnam nobody from the Troop was permitted to provide any direct intelligence to anybody but Task Force commander or the few senior officers (including intelligence officers) who were cleared to receive SIGINT generated intelligence. As events transpired, this instruction was honoured more in the breach than in the observance. If there was a need for others to receive such information it had to be in such a way as to protect the fact that the Troop was in Vietnam or, if this could not remain secret, the nature of its operations. Naturally, this proved impractical so astute Troop OCs devised ways in which the intelligence they gathered could be fed to commanders in the field – Australian and allied – despite the deployment orders and occasional reminders from DMI.
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The Troop increases its value After the Battle of Long Tan on 18 August 1966, the Task Force commander began to receive regular briefings on the locations and possible intentions of enemy units with which the Australians were in direct contact. By the time of the withdrawal of all Australian forces from Vietnam these briefings had become more regular and to a wider audience. In the last years of Australia’s involvement in the war the commanders and senior staff of the combat arms regularly received briefings directly from the Troop. As a result many Task Force operations were directed by the intelligence gathered by the Troop. Field commanders would even seek out this intelligence during operations in order to maintain complete situation awareness prior to proceeding with their mission. An after action report from one major joint operation (Operation TOLEDO) stated that it was driven by signals intelligence gathered by Australian and US operators. But members of the Troop did more than just receive and pass on intelligence gathered by themselves or their allies. There are also numerous examples of the Troop showing initiative in responding to the intelligence it was gathering. The following incidents are examples which demonstrate the initiative shown by the Troop: In early August 1970, messages were intercepted that revealed a large body of VC would be moving into the Hoa Long village to rest and replenish their stores. The Troop OC, realizing that there were no allied troops available, personally conducted a reconnaissance of the likely enemy approaches and most favourable ambush positions, and provided this information to the infantry dispatched to deal with the threat. The ambush resulted in 19 VC killed and six captured. Another later gave himself up to the Australians. (The full story of this episode is on page XXX.) When an analysis of the VC communications indicated that friendly forces were under imminent threat of a clash with the enemy the Troop quickly ascertained the identity of the friendly units or formations and urgent messages were sent out warning them of the impending enemy action. In one case an American patrol was identified as about to walk into a carefully prepared VC ambush. The Troop was able to warn this patrol in sufficient time for it to conduct an anti-ambush drill and inflict numerous casualties on the enemy. On those occasions when it was not possible to give sufficient warning by radio, an officer from 547 Sig Tp would fly to the allied unit and brief the commander directly. In this way the intelligence gathered by the men was able to save the lives of many Australian and American soldiers. In June 1969 a signal was picked up by the Troop and quickly identified as a major VC regiment preparing to launch an attack against soldiers of the Thai Expeditionary Division (the Black Panthers) at their base at Loc An. A warning was quickly sent out and the base defences put on high alert. A little after midnight the VC launched their attack but the Thai soldiers were waiting. Supported by American aircraft and artillery the VC was soundly beaten. The morning following the attack over 200 enemy dead were found outside the
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Thai perimeter, and hundreds of blood trails showing where many more dead and injured had been dragged off the battlefield. Without the alertness of the operators of 547 Sig Tp, their skills at accurately indentifying the location of the enemy forces and breaking their codes, the result would have been far different. Such action by the men of 547 Sig Tp was repeated many times throughout the Troop’s deployment to Vietnam. With the increase in intercept positions, and ongoing experiments enhancing the Troop’s capability for aerial and ground direction finding, the quality and timeliness of the intelligence being gathered contributed significantly to the tactical planning of allied operations. Despite this, being part of a chain of command separate to the other Australian units had both limitations and benefits. The main limitation concerned the fact that the product of signals intelligence, even that captured by the Troop, came initially directly from US sources. It was not until later in the war that the Troop was (officially) briefing commanders directly. This was a significant limitation on what the Troop was capable of providing by way of timely, accurate and effective intelligence during the early years of the Task Force when commanders at all levels were limited in their knowledge of enemy units or their locations. It also suggests why the Troop does not appear as a critical component of the Task Force’s operational planning at that time. On the other hand, a benefit of being separate to the Task Force was that the Troop was capable of having a significant impact on way in which the war was conducted at both the tactical and strategic levels, not just within the Australian area of operations but more widely. Most American direct support units worked primarily with their own formations but 547 Sig Tp provided a wider range of support to II FFV and its combat units operating within reach of the Task Force’s area of operations. In fact, the Americans found the intelligence gathered by the Troop to be of such high value that a liaison officer from the II FFV SSD visited the unit on a daily basis to receive a direct briefing on the identified enemy locations and assessments of their strength and intentions. The benefit of such close liaison was enhanced when, prior to the 1969 Tet holiday period, the VC followed their regular pattern and changed frequencies and callsigns. The Troop was one of the first SIGINT units in Vietnam to recapture their assigned targets and break their codes, warning the US forces of the intent by 274 Regt to renew operations against the ARVN and American forces operating along Route 15. By 1969 such confidence was shown in the Troop that detachments of Australian operators were regularly deployed to the field either in small independent teams, or in direct support of Australian and American operations. As a result of their initiative and persistence, by the end of its deployment the Troop was often viewed by Australian and US commanders as the best source of intelligence concerning enemy identity, locations and intentions. The Troop also developed (along with Australian scientific experts) what was widely regarded as the best Aerial (or Airborne) Radio Direction Finding capability in Vietnam, and set the groundwork for electronic warfare and SIGINT operations conducted by the Australian forces in all operations since 1975.
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History shows that despite the elongated and convoluted chain of command, in which there were many chiefs and far too few Indians, the Troop not only managed to achieve its primary mission, but to do so at a level far in excess of any expectations held by either US or Australian leaders. What I learned through my research is that despite the attitude of Australians then and now, the Troop was held in high regard by US commanders who on at least two occasions recommended the Troop for unit commendations during the war and in the years since. What follows is an outline of the ASA in Vietnam and how a small group of Australian signalers and Intelligence Corps analysts became an important cog in the US signals intelligence machine.
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PART TWO - THE ARMY SECURITY AGENCY
The ASA can trace its roots back to 1917 when a coding clerk with the American State Department, Herbert O. Yardley, persuaded the US government to create a cryptanalytic unit at the time the United States was entering the First World War. Yardley, whose hobby it was to break what others believed to be unbreakable codes, including those of his own government, was shocked to find how easy it was to do so. Out of curiosity he turned his hand to the codes of other nations and found many of them as easy to break. Realising that if he could break his own government’s codes and those of friendly nations, then so too could others. As the war in Europe intensified, Yardley’s efforts to convince his employers of the need to protect the nation’s codes and ciphers initially fell on deaf ears, but were soon joined by those of an officer in the War College Division of the War Department, Major Ralph Van Deman, Van Deman was an infantry officer who had previously served with the Military Information Division in Washington and the Philippines, and had undertaken undercover work in China. On his return to Washington in 1916 he was concerned at the level to which Military Intelligence had deteriorated. His principal concern was that information of strategic interest was not being actively sought or, when received, analysed for relevance. He suggested that a separate division of the General Staff be established to deal exclusively with military information. This suggestion was not acted on until the following year as America was about to enter the war, and the American Cryptographic Bureau, more often referred to simply as the Cipher Bureau, was created as the eighth section of the Military Intelligence Division with Van Deman as its first head. Many of the first recruits to the division were members of the Signal Corps with a long history of monitoring enemy communications, but little expertise at decoding messages. Upon hearing of Yardley’s concerns, in June 1917 Van Deman (now Colonel) appointed him as a First Lieutenant in the Signal Corps with responsibility for establishing the Codes and Ciphers Section of the Cipher Bureau (also referred to as the Black Chamber) One of the tasks of the newly raised Cipher Bureau – later named the MI8 – was to train cryptanalysts for the American Expeditionary Force being prepared to join the fighting in Europe and Siberia where a smaller expeditionary force had been deployed. With Britain and her allies locked in the struggle on the Western Front and the Middle East, America at this time remained neutral. It was therefore relatively easy to access the codes of all belligerents enabling Yardley and his team to hone their code breaking skills. By the autumn 1917 the sheer volume of messages requiring the attention of trained cryptographers began to overwhelm Yardley and his growing team. Many of these
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547 Signal Troop and the American Security Agency messages, gained by various (mostly unauthorised) means, were between diplomatic missions of countries with whom America expected to soon be in conflict, but as the conflict in Europe took on more of a global perspective, so too did the rate at which coded telegrams were being intercepted and brought to the Bureau. It was clear that additional support was needed if the intelligence gained from an analysis of these messages was to be of use to the US government and its agencies.
The birth of the US military cryptography Prior to the war the only facility in the US capable of solving enciphered messages was the Riverbank Acoustical Laboratories, an accredited acoustical testing agency created by George Fabyan, an eccentric philanthropist. Aside from his business interests, Fabyan built and funded the agency as an independent centre in which was employed a ‘community of thinkers’ researching, among other things, building construction, how sound is transmitted and the possibility of human levitation. A small section of the agency had been set up to enable staff to pursue any project of interest, one of which was the decoding of messages purportedly hidden within texts written during the reigns of Elizabeth I and James I. Employed by Fabyan to conduct this research, Elizabeth Wells Gallup believed she had identified many messages in the works of Shakespeare and would often travel to England to study his texts firsthand. William Friedman, a self-taught but highly competent photographer, accompanied Gallup on her many trips to England and soon also became interested in cryptography. Fabyan’s support to the work of Gallup and, by now Friedman, was more altruistic than scientific. He was reported to have felt that Gallup’s success was his success, especially if she could prove that there were secret messages hidden in the works of the English bard. He therefore brought to Riverbank many aspiring students keen to learn the work of cryptography and placed them under the supervision of Gallup. Once they had proved their ability they were placed on a salary and put to work with Gallup and Friedman’s expanding crypto team. While retaining an interest in deciphering the old English texts, Fabyan began to look for opportunities to expand his business interests. As it became clear that the US would soon find itself embroiled in the European conflict, Fabyan offered the services of Friedman and his team to the government. Riverbank’s early success at breaking codes sent to them by government agencies had, along with more than a little self-promotion by Fabyan, gained Riverbank a reputation for speed and accuracy at decoding the messages of foreign governments. Fabyan’s offer was quickly accepted and Riverbank became a training centre for recruits to the MI8. Upon his secondment to Yardley’s Cipher Bureau, Friedman was directed to create a team of cryptographers dedicated to deciphering the ever growing stock of coded messages. With the inclusion of the team from Riverbank the Cipher Bureau (by now referred to simply as MI8) gradually increased in capacity to include the creation of codes and ciphers, analysis and decode of communications, and in the event that written correspondence fell into their hands, shorthand messages and secret ink.
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While cryptographers and radio intercept operators went to the Western Front in support of General Pershing’s army, the bureau remained in the US throughout the war. Yardley continued in command of this group and spent the last few months of 1918 and a period afterwards working with the British and French cipher bureaus and learning their methods for solving enemy codes and ciphers.
“Chut, J’ecoute” – US intercept during World War One Intercepting enemy – or even potential enemy – communications has long been part of intelligence operative’s toolbox. The invention of the radio, and its application by the military, simply added another dimension to the expanding field of communications – or as it became known, signals – intelligence. When the American Expeditionary Force (AEF) arrived on the Western Front on 5 July 1917, General John J Pershing’s forces were already experienced in radio intercept and direction finding. During the Mexican Punitive Expedition of 1916-17 mobile radio vans known as ‘radio tractors’ purchased by the Signal Corps in 1914 were employed in intercepting and locating the Carrancista forces. The limited success achieved by these means so impressed General Pershing that he determined that a signals intelligence capability should accompany his forces when they were deployed to France. By the time of the arrival of the US forces, the British and French had honed their SIGINT capability to a high degree, but until 1917 these were primarily aimed at intercepting communications of the German navy, in particular the U Boats creating such havoc amongst convoys between America and Great Britain. While also intercepting German air and ground forces, the allies found that the enemy codes at the time were so poor, as was operator competence, that they had little problem reading the messages and learning their intentions. However, by the time of the AEF’s arrival the competence of the German communicators had increased and the use of radio direction finding was therefore taking on greater importance. Brigadier General Dennis Nolan was Pershing’s principal intelligence officer (G2). One of his first priorities upon arrival on the Western Front was to establish a team to analyse and read German coded messages. He gave the task to an artillery officer, Captain Frank Moorman who set about learning everything he could from his counterparts in the British and French intelligence. Naming his team the Radio Intelligence Section (RIS), Captain Moorman established his headquarters in a chalet at Chaumont close to the AEF General Headquarters at Toul in the Lorraine region of France. With the approval of the AEF G2, Captain Moorman also helped establish the first Signal Corps units tasked solely with intercepting the German forces and locating their positions. The first formed units were known as Radio Intelligence Sections of the AEF Radio Division, but this was changed to Radio Section in order to avoid conflict with the similarly named group under the Expeditionary Force’s G2 branch. The Radio Section was commanded by Captain (later Major) Robert Loghry who, although a Signal Corps officer, had limited experience at signals intelligence. He
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547 Signal Troop and the American Security Agency immediately arranged for his men to contact their British and French counterparts seeking advice, guidance, and wherever available, surplus equipment in order to build their intercept capability. Mirroring the British and French models, Captain Loghry created several intercept stations and immediately began capturing German radio traffic and reporting it back to the RIS at Chaumont. Captain Loghry’s teams regularly relocated in support of the allied operations. He also established radio direction finding (also called goniometry) and traffic analysis sections, collecting and analyzing not only traffic sent by German radio and telephone operators, but also press and government communiqués. With their headquarters at Marceaux Barracks in Toul and linked in with the French Second and Eighth Army intercept operations, the Signal Corps stations focused on both air and ground communications. In July 1918 they took over two French stations responsible for intercepting German air communications and later added a third. Messages intercepted by these stations were relayed to American and French pursuit squadrons resulting in many aerial combat successes. They were also able to provide early warning of artillery fire across much of Figure 4. US Radio Section intercept station Number 1 at Souily, 1918. the Western Front by analyzing messages which alerted German pilots to ‘no go’ areas. The ground intercept stations were mostly fixed to motor transport (also referred to as ‘tractors’) meaning that they could be moved as the forces maneuvered during combat operations. They established themselves behind the front lines and intercepted both radio and telephone communications between the German front line commanders. The results of their intercepts were initially relayed by courier back to Chaumont, but depending on the situation this could take 2-3 days. With the creation of the telegraphy system these intercepts were able to provide near real time intelligence. In May 1918 the Americans began to take over more of the French intercept sites, and in other areas provided Signal Corps personnel to jointly man stations that were under French command. These were supplemented by fixed (but movable) DF or goniometric stations which determined German Army and aircraft locations from the radio traffic or by compass (or aero goniometric) bearings. These stations were later established in trucks fitted with the DF equipment and capable of moving as the tactical situation dictated. As the war progressed from trench warfare to maneuver, seven aero gonio stations were merged with radio gonio operations enabling both fixed and mobile intercept and DF tasks to be undertaken.
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There is little available information concerning the type of equipment employed by the AEF DF teams. Up until World War II the most common system was the Bellini-Tosi direction finder. This system used signals from two crossed antennae (see Figure 5) or four individual antennae simulating two crossed ones, to mirror the radio signals in the small area between two loops of wire. The angle to the target radio source was then measured within the area between the loops; however this operation often took several minutes to Figure 5. AEF DF goniometric tractor perform meaning that the longer the enemy radio stayed on the air, the more accurate was the readings. As the war progressed the Germans began to employ shorter forms of communications meaning that intercepting and analyzing enemy radio messages became a more trusted form of intelligence than RDF. Despite these limitations, the goniometric system remained an invaluable tool in the hands of the AEF and allied intelligence analysts. Working closely with the ground intercept sites, the mobile stations moved with the advancing American and French forces during the St Mihiel (12-15 September 1918) and Meuse-Argonne (26 September-11 November) offensives. Since their inception these stations provided commanders with a continuous update of the German orders of battle, location of enemy positions, and early warning of aircraft and artillery attacks. When cryptographers trained by Van Deman and his team were deployed to France as part of the Military Intelligence Division, the ability to read German traffic increased exponentially giving the allies a tactical edge over the opposing forces. The military history of World War I gives little credit to the work of the Radio Section or the tactical and strategic achievements made by the allies due to their untiring work. According to one source an AEF Signal Corps officer was heard to remark that the unofficial motto of the corps was ‘Allo, J’ecoute’ (Fr. I am listening). He is recorded as saying that the motto for the Radio Section could have been ‘Chut, J’ecoute’ (Fr. Shh. I am listening).12
“Gentlemen do not read each other’s mail!” After the war MI-8 was disbanded, but the Cipher Bureau continued as The Black Chamber. It was moved to New York where it went by the title of the New York Commercial Code Company. Jointly funded by the State Department and the Army, and
12 An ironic choice of terms given that the patrols and ARDF operations conducted by 547 Sig Tp later became known as the ’Shush’ Patrols.
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547 Signal Troop and the American Security Agency with Yardley as its head, the bureau developed codes and ciphers for commercial use while covertly continuing to monitor communications (chiefly diplomatic) of other nations. The bureau’s expertise at code breaking also continued to grow, however, all of this changed shortly after Herbert Hoover was elected to office in 1929. Throughout the 1920s the bureau intercepted and cracked thousands of diplomatic messages, most notably those of Great Britain and Japan during the Washington Naval Conference of 1921. These messages continued to be read by Yardley’s team and, upon the election of the Hoover Administration, it was decided to share some of the intelligence with the incoming Secretary of State, Henry Stimson. Stimson took one look at the messages and was furious. He later recorded that his response was that ‘gentlemen do not read each other’s mail’, and immediately took steps to withdraw all funding from the Cipher Bureau. Left with no job, and because of the secrecy of his position, no pension, Yardley spent the rest of his life writing and consulting to business and foreign governments. Meanwhile, the Black Chamber files were transferred to the US Army Signal Corps and a new organisation raised known as the Signals Intelligence Service (SIS). With Friedman (now a Colonel in the Signal Corps Reserve) at its head the SIS’ interception tasks were expanded to include not only Japan but also Germany and Italy. During the Second World War the title was changed to Signals Security Agency (SSA) and on 15 September 1945 changed again to the Army Security Agency (ASA) reporting directly to the G2 (Intelligence) branch of the War Department. Shortly after World War II the US government centralised all military cryptologic organisations under the Armed Forces Security Agency (AFSA). In 1952 this agency was replaced by the NSA and increasing the focus from purely military signals intelligence to national security.
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PART THREE - THE ARMY SECURITY AGENCY GOES TO WAR
On January 1961, John Fitzgerald Kennedy was inaugurated as the 35th President of the United States of America. One of his first actions was to consider a request for support by the Government of the Republic of Vietnam (RVN) concerned at the growing Communist threat to that country. At the time no actual military support was being called for beyond assistance to train the South Vietnamese troops and, among others, build up their fledgling communications intelligence capability. In response to this request the NSA suggested that intercept and radio direction finding equipment be given to the Vietnamese, and at the same time the US should consider establishing its own intercept operations in that country. On 29 February 1961, President Kennedy formally approved a request to investigate the feasibility of deploying COMINT personnel to Vietnam. On 20 March the Department of the Army was informed that it was politically viable to deploy a small COMINT team to assist the South Vietnamese forces in their fight against the growing communist threat. On 29 April 1961, the US National Security Council met, at which time President Kennedy gave his formal approval for the deployment of ASA personnel to Vietnam. Within days the nucleus of a team had been formed at the ASA Training Center and School at Fort Devens, Massachusetts. Stores and equipment were withdrawn from US based units and dispatched to Fort Devens where, while they awaited their departure, the ASA contingent formed itself into the 400th USASA Operations Unit (Provisional). The initial approval was for the deployment of a 78-man intercept and direction finding team under a program entitled WHITEBIRCH. With them went a 15-man training team under another program, SABERTOOTH, to work with the Army of the Republic of Vietnam (ARVN) to increase and enhance their intelligence gathering capability. Two weeks after it was created, the 400th USASA Operational Unit (Provision) embarked for Vietnam, arriving on 14 May 1961, four years before any major ground combat unit arrived in that country. Renamed the 82nd Special Operations Unit, the officers and men worked together in an old aircraft hangar. Dressed in civilian clothes to further disguise their identity and military role, their working conditions consisted of camp stretchers and empty crates for chairs and desks. The soldiers carried no military identification and lived downtown in the Majestic Hotel. The hanger used by the soldiers was part of the South Vietnamese Army’s Joint General Staff Compound at Tan Son Nhut Air Base. The buildings were old and prone to
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547 Signal Troop and the American Security Agency frequent flooding in the wet season. With no air-conditioning they were stiflingly hot with temperature regularly exceeding 100 degrees. Working areas were sectioned off with ration boxes and spare equipment. Because there were so few chairs the tables upon which the operators and analysts worked were constructed four feet high so that for most of their working day the men had to stand, and during the monsoon rains they were standing in water several inches deep. Despite the less than optimal working conditions, the men were soon searching the airwaves for North Vietnamese and Viet Cong radio signals. They also conducted site surveys for a direction-finding network and in June 1961 commenced DF operations at Nha Trang, Ha Tien in Kien Gian Province (later relocated to Bien Hoa air base) and Vung Tau in Phuoc Tuy Province. With Vietnamese soldiers providing security, direction finding teams initially began working with AN/TRD-4 DF equipment (Figure 6) designed to locate enemy transmitters behind enemy lines. However, these were found to be inadequate at
Figure 6. AN/TRD-44 Direction Finding unit. accurately locating transmitters established within Source of image unknown. friendly areas of operations therefore the unit adopted jeep-mounted AN/PRD-1 direction finders. While marginally more effective than the AN/TRD-4 equipment, the AN/PRD-1 suffered one shortcoming: Introduced into the US Army in October 1955, the equipment was bulky, and required the operators and their equipment to be relatively close to the enemy in order to accurately locate their position. The further they were from the enemy the less confidence would be held in the accuracy of the plots (known as ‘cuts’ – the direction to the enemy transmitter, or ‘fixes’ – the location of the enemy transmitter). As a consequence AN/PRD-1 teams found it necessary to locate themselves closer to where the enemy forces were suspected to be. This meant leaving Figure 7. AN/PRD-1 Direction Finder mounted on established and well protected bases and a jeep. Source unknown. travelling – at the time almost always by road – out into the jungle in order to achieve their mission. On 22 December, the ASA suffered its first casualty. Specialist 4th Class (Spec 4) James T Davis was killed in an ambush near the old French garrison at Cau Xang, 10 miles from Saigon. Davis was seated in the front of the truck in which the ARVN specialists
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547 Signal Troop and the American Security Agency were travelling when a command detonated mine was exploded as they drove over it. He managed to crawl clear of the vehicle but, while marshalling the ARVN troops and engaging the VC, he was shot and killed. His was the first death in combat suffered by the ASA – and the US Army – in what by now was termed the Vietnam War (called the American War by the North Vietnamese), and would not be the last. In tribute the unit’s headquarters compound at Tan Son Nhut was named Davis Station. Davis’ death also raised questions about using ground based mobile DF systems when the same results could be obtained, at less danger, from the air. Experiments soon commenced using light aircraft fitted with DF equipment and various antennae arrangements in an attempt to resolve the problem of identifying and tracing enemy locations while maintaining a safe distance. The first flights in March 1962 were low and slow, and the aircraft could carry only two people. Within days soldiers were calling it the TWA – the Teeny Weeny Airlines.13 Eventually more suitable accommodation was found for the men and in 1963 they were moved into the WHITEBIRCH operations area where they were assigned overall control of ASA operations in Vietnam. The intercept operators now had relatively comfortable, and certainly more waterproof, caravans and well constructed buildings from which to conduct their search of the airwaves. They were also now in uniform and appearing as what they were – soldiers of the US Army. To protect their real mission, the unit was listed on the US Order of Battle (ORBAT) as the 3rd Radio Research Unit (3rd RRU).14
The ASA grows Operationally 3rd RRU was called USM-9J and subordinate to USM-9 in the Philippines. The original mission consisted mainly of analysing radio traffic captured by the South Vietnamese SIGINT teams. Employing leftover French intercept and World War II era DF equipment, the South Vietnamese teams comprised around 100 officers and men, with collection sites at Saigon and Danang. A third was established at Can Tho in the Mekong Delta. In 1961 the CIA gave the South Vietnamese six AN/PRD-1 mobile HF DF sets through which the 3rd RRU gathered intelligence on VC locations. The ASA teams continued to employ the AN/TRD-4 equipment, three of which were mounted in vans located at Nha Tran, Can Tho and Bien Hoa with control in Saigon. But despite their best efforts, the WHITEBIRCH program was a failure. It was constantly short of manpower and in the humid jungle environment the ground
13 The introduction of ASA and USAFSS ARDF is discussed on pages XXXX – XXXX. 14 In order to maintain security concerning their operations and to mask their real purpose, all ASA units – including the Australian 547 Signal Troop (547 Sig Tp) – were referred to as Radio Research units.
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547 Signal Troop and the American Security Agency wave, upon which the AN/TRD-4 relied for accurate bearings, faded considerably after only a few kilometres. The sky way came down at too step an angle to be usable, and the skip zone between the ground and sky waves was nearly 150 kilometres, meaning that most ASA sites were in the skip zone. The reliance, therefore, was mainly on the ARVN for DF intelligence. In 1963, the 3rd RRU established its first major field base at Phu Bai south east of Hue which, the following year, was given the cover name of 8th Radio Research Unit (8th RRU). This was later changed to 8th Radio Research Field Station (8th RRFS) and from its earliest days it was clear that the work of this station would grow exponentially as targets were identified and the value of their intercepts analysed and reported through the channels to Fort Meade. With the increasing number of intercept tasks came a call for more men and equipment, and for a time this unit was the largest signals intelligence station in the world in terms of positions dedicated to 24-hour communications intercept. In 1965, the deepening political crisis throughout the south, and the increasing defeats experienced by the ARVN, motivated the US to consider expanding its ground support to South Vietnam. By July that year the ASA had three units fully committed to the conflict: The 3rd RRU at Tan Son Nhut airfield conducting offensive intelligence gathering (communications intercept and analysis, direction finding etc.), the 7th RRU undertaking defensive communications tasks (communications security), and the 8th RRFS at Phu Bai. It was also recognised that increased troop numbers would require a larger signals intelligence footprint and the 303rd Army Security Agency Battalion (303rd ASA Bn) – at the time at Camp Wolters in Texas – and 313th Army Security Agency Battalion (313th ASA Bn) – at Fort Bragg in North Carolina – were warned for deployment to Vietnam. On their arrival in Vietnam in March and April 1966 these units were renamed as Radio Research Battalions and deployed to the field – the 303rd Radio Research Battalion (303rd RR Bn) to Long Binh and the 313th Radio Research Battalion (313th RR Bn) to Nha Trang. They, along with 8th RRFS, were given responsibility for all intercept operations throughout Vietnam, including provision of detachments in support of the ever growing number of field units arriving in Vietnam. As the number of US and allied troops continued to grow, the ASA realised that the 3rd RRU did not have sufficient personnel to control and direct the growing country-wide signals intelligence effort as well as fulfill its own operational needs. Consequently, on 1 June 1966 the 3rd RRU was disbanded and four new units raised. These were: 509th RR Gp which assumed administrative control of all ASA assets in Vietnam (excluding 547 Sig Tp which was administered under HQ 1 ATF). 224th Aviation Battalion (Radio Research) later called the 224th Radio Research Battalion (224th RR Bn), primarily used for airborne operations and operating out of Tan Son Nhut airport in Saigon in support of operations across Vietnam 175th Radio Research Company (175th RR Coy) which took over the 3rd RRU’s collection and processing missions, and
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Radio Research Communications Unit—Vietnam (RRCUV) The 175th RR Coy was deployed to Bien Hoa where it continued to report to USMACV but placed under direct control of the newly raised 509th RR Gp in Saigon. The 303rd RR Bn was established at Long Binh under operational control of II FFV and with responsibility for collecting, processing and reporting to 509th RR Gp the activities of all Direct Support Units (DSUs) within III CTZ. Although never listed in official 303rd RR Bn correspondence, 547 Sig Tp was one of these DSU’s.
509th Radio Research Group Upon its formation 509th RR Gp was tasked with providing command and control over all subordinate radio research units, support COMUSMACV, and oversee the SIGINT training of the South Vietnamese allies. To achieve this, the five major subordinate units – stationed as far north as Quang Tri, near the border with North Vietnam, and Cam Tho in the Mekong Delta– were restructured as subordinate to the 509th RR Gp. These were: 8th Radio Research Field Station (formerly the 8th RRU) providing general support for USMACV two Radio Research Battalions – the 303rd and the 313th – overseeing the increasing number of companies and detachments directly supporting combat forces in the field 224th Aviation Battalion (Radio Research) providing aerial SIGINT support for American and allied forces in Vietnam; and 101st Radio Research Company (formerly the 7th RRU) directing the group’s communications security efforts Aside from a small processing, analysis and reporting branch, the 509th RR Gp acted primarily as an administrative headquarters providing overall supervision and support to all ASA units and detachments scattered throughout Vietnam. With few exceptions (including 547 Sig Tp), the movement and administration of all ASA personnel was the responsibility of this headquarters, a continuous challenge as many DSUs regularly moved around the country following their supported units which were under separate command arrangements. Intelligence gathered by 509th RR Gp was, along with other information, disseminated to senior commanders through detachments of the US Army Special Security Group (USASSG) established in 1967 under the Assistant Chief of Staff for Intelligence— Vietnam. The SSG was itself recognised by the award of the US Meritorious Unit Commendation for the timeliness and accuracy of its briefings. These were enhanced by the efforts of 509th RR Gp and its sub-units to quickly identify highest priority threats and relay these through to the higher command intelligence analysts.
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Figure 8. 509th RR Gp units in 1967. Not shown here is 547 Sig Tp under operational control of 303rd RR Bn. Source https://thearmysecurityagency.com/rru---asa-awards.html While the 509th RR Gp’s cantonment area was established on the west side of Tan Son Nhut Air Base, in October 1967 the Group’s Headquarters Company moved into Joint General Staff Compound in Saigon. During the Tet Offensive of 1968, enemy elements penetrated within 100 metres of the headquarters before being driven off. In August 1972, the group headquarters moved back to Tan Son Nhut Air Base for several months before ending its service at the USMACV headquarters compound. As the peace negotiations stepped up pace in late 1972 and early 1973, the Group’s personnel drawdown was rapid. In July 1972, the Group had more than 2,100 personnel assigned. By December, the number was down to 195 and in March 1973, 509th RR Gp was disbanded, and all personnel returned to the USA. For almost twelve years, from 1961-1973, 509th RR Gp was the chief ASA organisation in the Republic of Vietnam. In that time, the Group earned 15 campaign streamers, four Meritorious Unit Commendations, and three Vietnamese Crosses of Gallantry. And that was just the headquarters! Sub-units were awarded many more. The following citation was awarded to 509th RR Gp, and all ASA units in Vietnam, during the period indicated.15
15 It is not known why 547 Sig Tp was not included on this list. Discussions with former senior officers of 303rd RR Bn and 175th RR Coy reveal that few knew of the Troop’s existence or its role in the SIGINT war. Citations have recently been written for retrograde award of the MUC to 547 Sig Tp but not approved by the US Department of Army.
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DAGO 43/72 Meritorious Unit Commendation By direction of the Secretary of the Army the Meritorious Commendation is confirmed for the following named unit: 509th Radio Research Group and its assigned units: Radio Research Communications Unit Vietnam Headquarters and Headquarters Service Company, 509th Radio Research Company 335th Radio Research Company 101st Radio Research Company 8th Radio Research Field Station (20LC) 265th Radio Research Company (10LC) 407th Radio Research Detachment 303rd Radio Research Battalion 175th Radio Research Company 337th Radio Research Company 371st Radio Research Company 372nd Radio Research Company 409th Radio Research Company 856th Radio Research Detachment 313th Radio Research Battalion 330th Radio Research Company 374th Radio Research Company 328th Radio Research Company 404th Radio Research Detachment The citation reads as follows: The 509th RADIO RESEARCH GROUP and its assigned units distinguished themselves while in support of military operations in the Republic of Vietnam during the period 1 January 1969 to 31 December 1970. Demonstrating extraordinary diligence, aggressiveness and professionalism, the officers and men of the group provided truly outstanding special intelligence support to Allied forces operating through the theatre. Radio research teams moved directly in the assault with US combat elements supplying on the spot intelligence, while other long range analyses of the group resulted in troop and weapons employment. In the performance of its mission, the group demonstrated that it could provide significant intelligence on enemy plans and locations in a timely manner, thereby convincing combat commanders of the crucial quality of radio research support. While directly supporting combat operations, the 509th RADIO RESEARCH GROUP also greatly expanded their advisory efforts resulting in significant and far reaching advances in the program of Vietnamization. Through their great personal fortitude and determination unit personnel continued to expend the maximum effort to accomplish their mission, thus contributing immeasurably to the Free World military effort in the Republic of Vietnam. The remarkable proficiency and devotion to duty displayed by the members of the 509th RADIO RESEARCH GROUP are in keeping with the highest traditions of the military service and reflect distinct credit upon themselves, their unit and the Army Forces of the United States. 303rd Radio Research Battalion The 303rd RR Bn had a long and distinguished military history. This unit was intimately involved in action during the Second World War at Normandy and the Battle of the Bulge, and again throughout the Korean War before being disbanded in 1955. The battalion was
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547 Signal Troop and the American Security Agency reactivated on 15 June 1962 at Camp Wolters in Texas as Headquarters and Headquarters Company, 3rd ASA Bn, and because it contained a large number of soldiers from the Lone Star State within its ranks, it was natural that it would become known as the Longhorn Battalion. In time the Longhorns would become the most highly decorated military intelligence battalion in the history of the ASA. Upon its arrival in Vietnam on 12 April 1966, the 303rd ASA headquarters company was given the cover designation of 17th RRU and assigned to the 3rd RRU. The changes sweeping through the ASA in Vietnam during June and July 1966 saw the battalion assigned to II FFV and moved to Long Binh. On 1 June the battalion came under operational control of 509th RR Gp and three weeks’ later, on 29 July, their designation was changed to 303rd RR Bn. Available for tasking against targets anywhere throughout the South East Asian area of interest, the battalion was primarily responsible for handling all Communist communications in provinces around Saigon and south into the Mekong Delta – covering most of VC military regions VI through IX. Although changing as the operational situation dictated, for most of its deployment to Vietnam the 303rd RR Bn had the following units under its operational control:16 Unit In support of Unit designator 303rd RR Bn II FFV USM614 335th RR Coy 9th Inf Div USM615 337th RR Coy 1st Inf Div USM629 372nd RR Coy 25th Inf Div USM633 404th RR Det 173rdAbn Bde USM628 408th RR Det 196th LIB USM617 409th RR Det 11thArmd Cav Regt USM636 856th RR Det 199th LIB USM616 Det 547 Sig Tp 1stATF AUM352 For its actions during the war, the battalion received five Meritorious Unit Commendations (Army), the Republic of Vietnam Cross of Gallantry with Palm, and the Republic of Vietnam Civil Action Honor Medal, First Class citation.17 The following citation was raised for the award of one of the US Meritorious Unit Commendations received in 1968. This citation illustrates the value placed on the battalion’s contribution to the allied war effort:
16 Towards the end of the war some of these designators changed while other units were brought under operational control of 303rd RR Bn. 17 As of the date of writing, the only award made to 547 Sig Tp is the RVN Gallantry Cross with Palm unit citation, presented in 2018.
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DAGO 17/68 Meritorious Unit Commendation By direction of the Secretary of the Army the Meritorious Commendation is awarded to the following named unit of the United States Army for exceptionally meritorious achievement: The citation read as follows: The 303rd Radio Research battalion and its assigned and its attached units: Headquarters and Headquarters Company, 303rd Radio Research Battalion 175th Radio Research Company 335th Radio Research Company 337th Radio Research Company 372nd Radio Research Company 404th Radio Research Company 408th Radio Research Company 409th Radio Research Company *856th Radio Research Detachment For exceptionally meritorious achievement in the performance of outstanding services: The 303rd Radio Research Battalion and its assigned and its attached units distinguished themselves in support of military operations in the Republic of Vietnam during the period 1 June 1966 to 31 July 1967. The Battalion demonstrated fortitude, uncommon skill, and unswerving dedication in providing timely and accurate intelligence to the II Field Force Vietnam. Displaying phenomenal versatility, the men expeditiously met each commitment and kept pace with the fluid combat situation. With professional skill and unrelenting effort, they labored for in excess of normal duty hours to ensure that all elements of the II Field Force received the best intelligence information. With superb foresight and rare adaptability the 303rd Radio Research Battalion overcame and minimized the problems inherent in providing intelligence support during a period of rapid increases in the intensity and scope of combat operations. They provided complete intelligence support to the combat soldier, which earned them the praise and admiration of combat commanders. Through their initiative, resourcefulness, flexibility and readiness to resort to the expedient, the battalion members have materially contributed to the counterinsurgency effort in the Republic of Vietnam. The remarkable proficiency and devotion to duty displayed by the members of the 303rd Radio Research Battalion are in keeping with the highest traditions of the military service and reflect distinct credit upon themselves and the Armed Forces of the United States.
COLLECTION MANAGEMENT AUTHORITIES To eliminate duplication of intercept between the DSUs, 509th RR Gp delegated responsibility for the control and assignment of major VC and NVA military targets (and, later, Cambodian and Laotian targets) to units designated as Collection Management Authorities (CMA). Throughout the war these were: 8th RRU in I CTZ, 330th RR Coy in II CTZ, 175th RR Coy in III CTZ, and 335th RR Coy in IV CTZ. CMAs were established to address the problem of increasing calls from the combat forces for specific intelligence collection requirements. The purpose of CMAs was
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547 Signal Troop and the American Security Agency therefore to enable a systematic coverage of the SIGINT cycle through the establishment of a data base reflecting the requirements of COMUSMACV and subordinate commanders. CMAs collated the results of all signals intelligence activities within their area of responsibility, and conducted an evaluation of the results achieved through intercept and DF operations. All CMAs reported to 509th RR Gp who maintained a continuous monitoring of intercept and DF activities across Vietnam. These were reported at the highest levels to the SSG at USMACV, and at field force level to SSDs who compiled the results of SIGINT activities and analyses with intelligence gained from other sources. This effort was made more effective and efficient when CMAs ceded management of lesser priority tasks were to subordinate units and DSUs. The CMA to which 547 Sig Tp was attached was the 175th RR Coy at Bien Hoa. The two units developed a very close personal and working relationship, often swapping intercept and ARDF operators in order to gain experience at their respective operating procedures. This relationship was maintained throughout the war until the Troop’s withdrawal in December 1971.
175th Radio Research Company As the CMA supporting II FFV, 175th RR Coy had major coverage of the VC and NVA communications networks in the Saigon and Mekong Delta regions. During the Cambodian operations they also had responsibility for analysing communications from within Laos and Cambodia. The 175th RR Coy was a vital link in the complex chain of signals intelligence capture and dissemination in the southern half of South Vietnam. As a CMA their responsibility included tasking DSUs, the collection and management of SIGINT and other intelligence relevant to communications and DF reporting, and the collection, decryption and translation of intercepted communications. The most urgent and perishable intelligence of tactical significance was sent out to commanders of tactical units in a TACREP (Tactical Report). These alerted commanders to immediate threats and enhancing their situational awareness. An example of a TACREP concerning an intercept and decryption carried out by 547 Sig Tp is at Figure 9. Like all CMAs, 175th RR Coy also collated all intelligence relevant to II FFV (including intelligence gathered through the Phoenix Program) and maintained a battle map showing confirmed and suspected locations of VC and NVA formations. These maps would be kept for a week with different coloured pins on their maps identifying the day each update was made. Reports were also maintained on enemy movements, strengths, and possible intentions. To assist in this they had dedicated battlefield intelligence detachments with responsibility for recommendations for and technical tasking of ARDF/collection
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547 Signal Troop and the American Security Agency missions. Daily and weekly Tactical SIGINT Summary reports would be compiled and sent out to selected addressees detailing intelligence gathered over the previous period. (See Figure 10 below for an example of Daily Tactical SIGINT Summary report.)
Figure 9. Example of TACREP 7 January 1968 The 175th RR Coy was also the net control for all airborne direction finding activities (officially referred to as the WHITEBIRCH MRDF network) within II FFV. The CMA Airborne Systems Management Section (ASMS) reviewed locations of key targets, suggested areas in which to conduct search and allocated time-over-target for missions. They also had a key role in identifying targets for harassment and interdiction (H&I) artillery fire, and briefing other air and ground fire controllers on likely targets. Prior to each ARDF mission packages of technical data and supplemental ‘cherry sheets’ were prepared for Army and Air Force aviation units. These sheets would list information on each target, such as callsigns, frequencies and schedules. (For most Australian ARDF operations this material was also prepared by intelligence officers attached to the Troop.) Once airborne the ARDF crews had access to additional data from DSUs in the area, including 547 Sig Tp where a separate radio was dedicated to this net. Like all CMAs, 175th RR Coy prepared intelligence and after-action reports, and provided technical feedback to the DSUs within their area of responsibility. SIGINT reports were sent to USMACV every six hours across dedicated communications channels and employed this as a switchboard for information and analysis being sent up and down the ASA chain of command.
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Figure 10. Example of Daily Tactical SIGINT Summary report Towards the end of the war the focus shifted from actions directed solely towards defeating the VC and NVA forces on the ground and towards eliminating the Central Office for South Vietnam (COSVN), the main headquarters for communist operations in South Vietnam. In 1970 the COMUSMACV developed an ambitious plan to deploy US and ARVN troops across the border into Cambodia in search of the COSVN headquarters despite that country’s declared neutrality. The plan was to cross the border at several points in the north and west of III CTZ. During this operation the 175th RR Coy was tasked with managing the interception of all long-range Morse communications which could be clearly heard across most of the II FFV area of responsibility. In order to intercept short-range Morse and voice communications in and out of Cambodia, 303rd RR Bn directed DSUs from III CTZ to deploy forward with the advancing troops. The 175th RR Coy had to reprioritise tasking for other DSUs in the
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Tactical Zone, including 547 Sig Tp, to ensure that coverage continued uninterrupted during the Cambodian operation.18 The speed at which the US and ARVN forces advanced into Cambodia meant that instead of sending reports every six hours, the 175th RR Coy had to step up the rate of reports to every 3 hours. On one day the company sent wrap-up reports on the VC COSVN headquarters every 30 minutes, containing information on the time VC units came on the air, time they ceased transmitting and units with which COSVN was in contact. On top of this they sent summary reports twice daily to IIFFV and daily to 509th RR Gp. In June 1971, as a precursor to the planned withdrawal of all US and Australian forces from Vietnam, the 175th RR Coy began to wind down operations. Changing its name to 175th RR Field Station, the unit returned to Saigon in September 1972, and on 26 February 1973 ceased operations and all personnel returned to the USA.
DIRECT SUPPORT UNITS As the number of independent divisions and brigades increased throughout 1966, 303rd RR Bn recognised that there were insufficient detachments available to support all ground forces. Many of the larger formations arrived in country with organic SIGINT detachments attached as part of their ORBAT, but like 1 ATF many did not. This posed a problem for 509th RR Gp, especially as many of those arriving throughout 1966 were highly mobile or independent infantry and marine units requiring support arranged on their arrival. The solution was to create separate detachments, known as Direct Support Units (DSUs), assigned to each brigade or battalion and capable of operating independently in support of these formations. Direct Support Units – DSUs – were based on a company-sized grouping. Each US Division was allocated an ASA company from which detachments were formed to support brigades or regiments. Independent brigades were allocated independent ASA detachments. (547 Sig Tp was variously referred to in Australian records and reports as Detachment 547 Sig Tp or 547 Sig Tp Det.) Targets assigned to DSUs by CMAs were usually those of greatest interest to the supported command; however during high tempo operations targets could be assigned to DSUs outside of CMA’s area of responsibility. This allowed DSUs to be employed in direct support of their tactical command, and at the same time in general support of other formations or divisions. During operations DSUs deployed along with the tactical commands they supported in order to provide commanders with timely signals intelligence from manual Morse collection and ground or airborne direction finding. On occasions they were also
18 General Freeze, former commander 303rd RR Bn, in discussion with the author, stated that there was so much going on at the time that he doesn’t recall retasking 547 Sig Tp, but would be surprised if doing so had not been factored into the intelligence plan.
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547 Signal Troop and the American Security Agency able to provide intelligence from intercepts of voice radio communications or as a result of wiretaps. Their mobility, coupled with fixed base positions, enabled all DSUs to intercept enemy communications, provide ARDF and SRDF tip-off information, and receive resulting fix reports from other special identification techniques (SIT) sources (eg, radio fingerprinting19, operator analysis, DF etc.). This enabled their supported command to be proactive in their tactical planning. The DSUs also had mobile positions for air-to-ground communications to control Airborne Radio Direction Finding (ARDF), for ground-based AN/PRD-1 Short Range Direction Finding (SRDF), and from which to conduct manual Morse and voice intercept. Each US DSU employed four positions at its base camp and one or more mobile positions. Added to these were the ten fixed Morse or voice intercept positions at 547 Sig Tp, along with one mobile position mounted in an M577 ACV. The Troop also deployed aerial direction finding and, after 1969, a man-pack mobile DF system. Most DSUs were raised from established US Signal Corps units deployed from the USA or elsewhere, or made up of reinforcements arriving directly from training in America. Originally they consisted of a headquarters element and three platoons, one each for undertaking communications security tasks, communications and intercept/jamming. Prior to deployment to Vietnam the units were stripped of their electronic warfare and electronic intelligence gathering capability and their VHF intercept capability as these were designed for a European battlefield. Upon deployment, each company was revamped to enable them to intercept enemy voice and Morse transmissions, and to receive, process and record ARDF tasks. In this new role each company was allocated a complement of five ¾ ton truck- mounted mobile manual Morse intercept positions, and intercept and single-sideband air- to-ground ARDF tip-off positions. They were also allocated five man-pack voice intercept systems. Each mobile group consisted of two HF/VHF intercept positions, with an R-392 (HF), R-744 (VHF) and AN/PRD-1 SRDF equipment. Because the VC and NVA had greater reliance on Morse code than voice for their communications, each company also had two HF positions dedicated to Morse intercept. Each DSU platoon consisted of a number of collection teams which could be deployed as 2-3 man teams establishing a DF position at the forward edge of the supported unit’s area of operations. A larger team could comprise a mix of Morse Intercept operators (in US military parlance, their military occupation specialisation – MOS – was 05H), Voice Intercept Operators (98G) and a Traffic Analysts (98C). They may include a Cryptanalysts (98B) and Translator/Interpreters (04B) as Voice Intercept Operator. DF teams could also have a technician specially trained to repair direction finding equipment
19 Identifying a radio transmitter by is characteristics.
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(05D).
Figure 11. AN-TRD23 ground based direction finding system. Source unknown. When deployed to a relatively fixed location such as a Fire Support Base, DSUs would often have Tactical Communications Center Specialists (MOS 72B) operating voice communications and radio teletype links for the collection teams. More often, however, the teams were so widely dispersed that they required relay stations to be established between the teams for routing communications back to headquarters. From 1968 many US operators and analysts cross-trained to operate and deploy the AN/PRD-1 High Frequency Direction Finding set, however these went out of use by the end of 1969 with preference given to the more reliable AN-TRD23 ground based system (Figure 11). When a US division or independent brigade deployed to the field it often did so in battalion sized formations. To support the deployment DSUs would create a mobile team collocated with the supported unit’s command post. Here they would Figure 12. Inside the AN/TRD-23. Source Steve Roberts maintain air-to-ground communications with any ARDF aircraft supporting the operation, and a ground-based SRDF capability to supplement the DF task. They would also deploy limited Morse and, if required, voice intercept teams. These teams would comprise two or more semi-permanent groups with two positions sited at the base camp or FSB and the others free for mobile operations.
ARDF The ambush in which Spec 4 Davis was killed in 1961 generated a search for a safer means for collecting intelligence on enemy locations. The most obvious solution was to place DF
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547 Signal Troop and the American Security Agency equipment in an aircraft. This was not a new innovation as the French had some success with aerial direction finding in their fight against the Viet Minh, but these were only achieved once the technical problems were overcome. Aircraft flying at the optimum level were high enough to receive both ground and sky waves, and accuracy of any bearings was degraded due to the on-board system reading the ground wave while the aircraft itself, acting like a large sky wave antenna, read signals being received from a different direction. This was the first of many problems which needed to be addressed by the US Army and Air Force engineers. The ASA takes to the skies The US Army had been trialling ARDF since November 1961, both for their own purpose and to assist in the establishment of an airborne capability with the RVN forces under the SABRETOOTH program. The trials with the RVN were initially funded by the CIA, but within a year the ASA followed this with their own program to train and equip the South Vietnamese forces. The ASA experiments involved the use of rotary wing aircraft but these proved impractical due to static caused by the onboard electronics. A solution was found by modifying fixed-wing aircraft employing a simple system whereby two dipole antennae were fixed to the leading edge of the aircraft’s wings connected to a radio receiver housed in the fuselage. Thus the aircraft became the direction finder. In March 1962, the ASA launched its first ARDF missions using single engine U6A De Havilland Beaver aircraft procured from the Army Signal Corps and flown by pilots borrowed from the Transportation Corps. Designated the AN/ARD-15 ARDF system, the first three aircraft were fitted with a modified AN/TRD-16 ground direction finder with the space between the antennae widened and fixed to the forward edge of the wings about 40 feet apart. Cables were installed inside the aircraft connecting the antennae to an R-390/URR receiver mounted in the cabin. The aircraft at the time had no navigation system so the pilot had to learn to fly over a point on the ground that he could identify on his map, and keep the aircraft steady while reading the onboard gyrocompass. To make this more difficult the wings had to be kept level which required the pilot to ‘fishtail’ the aircraft while the operator searched for the ‘aural null’ (the point at which the signal is at its weakest). Once found the operator would inform the pilot who would note the heading. Despite having to fly directly at the enemy transmitter in order to identify its location, these flights achieved a great deal of success. However, until the arrival of US ground troops in 1965 the intelligence gathered by these aircraft had to be analysed and passed to the ARVN for follow up. These experiments were successful in identifying the location of the enemy forces, but were less successful in determining the number and capability of the troops involved. The first major ARDF led ARVN action at Ap Bac in
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1962 proved disastrous with heavy casualties suffered by both South Vietnamese and US forces. The increase of US forces arriving in Vietnam from 1965 led to further demands for ARDF support. By then the ASA had 30 aircraft available and were employing advanced means for communicating results directly back to the units on the ground. While confidence was held in the ARDF ability to identify the location of the enemy, collateral intelligence was still required in order to determine their strength and intentions.
The US Air Force joins the fight The United States Air Force Security Service (USAFSS) was the equivalent of the ASA. Since 1961 this group had also been experimenting with aircraft fitted with DF equipment. Under command of the 2nd Air Division (2nd AD), stood up under the authority of USMACV to provide air support to the RVN Armed Forces, the first experiments were designated ‘Project Farm Gate’ and ‘Project Hill Hattie’. These projects employed Douglas C-54 Skymaster aircraft fitted with photographic, infra-red reconnaissance and a type of homing radio direction finder. The experimental aircraft were integrated with 3rd RRU DF missions but due to limited success were soon abandoned. Further trials were undertaken under ‘Project Mona Hi’ with the US Navy employing World War II era Douglas EC-47 Dakota aircraft. This project was later taken over by USAFSS under a program entitled ‘Hawkeye’ and with aircraft fitted with a TACAN navigational receiver and triangularly arrayed dipole antennas. In this configuration the aircraft could fly parallel to their target obviating the need to repeatedly turn towards the enemy position (and by doing so warn the enemy that their transmissions were being tracked). While the direction finding capability proved effective, other items of equipment proved problematic. By the end of 1963 the aircraft had departed Vietnam. The Air Force also had an interest in using the aircraft to extend the reach of their intercept operations. In early 1964, under a project named ‘Sour Grapes’, two EC-47s were modified in Korea and flown to Vietnam to conduct hearability tests targeting Chinese and Vietnamese VHF voice communications. The equipment worked well and the results of these trials were encouraging, but underwhelming. In July the following year 2nd AD expressed a requirement for Tactical COMINT in South Vietnam using two JC-47s formerly employed with the Air Forces Airborne Emergency Reaction Unit, (ABERU) but at the time excess to requirements. These aircraft were required to ‘fly near areas where VC tactical units are (suspected) to be operating low powered Morse and voice communications.’ The rationale for the operation, under the program title of ‘Drill Press’, included the following: ‘In order to properly follow (the VC) movements and be able to determine intensions of VC units for immediate action and if DF capability exists, to determine enemy locations, airborne intercept of the communications of these units with air ground reporting capability is required. Both voice and Morse intercept will be utilized if the latter is used by tactical VC units. In engagements such as the recent ones at Dong Xoai, Song Be and Quang Ngai, we must be able to follow the
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VC as they repeatedly attack and reposition themselves for re-attack from a different position. The tactical communications used in these operations by the VC will reveal their intentions and possibly locations. The ABERU aircraft, with skilled language technicians aboard will immediately report any such information to a forward air controller (FAC) that he may direct the fire of close support aircraft. The ABERU aircraft may also act as FAC….’20 As ambitious as this challenge was, the USAFSS immediately identified a major stumbling block: The Service had few Vietnamese or Cambodian linguists, and these were already employed on essential tasks elsewhere. Moreover, NSA was lukewarm about the proposal which created tensions throughout the SIGINT community. Nevertheless, the USAFSS went ahead and began configuring aircraft using its own resources. These aircraft were from then on generally referred to as Drill Press and the USAFSS was given 120 days to prove their worth. From experiment to operation On 27 December the first ABERU EC-47 arrived at Yokota in Japan and by 3 January was ready for delivery to Tan Son Nhut where it was to be fitted with radio receivers. On 10 January the first familiarisation flight was launched and tests conducted to compare airborne versus ground intercepts. The Drill Press aircraft immediately began to show positive results, identifying around 25 new VC communications links each mission – and two missions were being flown each day. In March the USAFSS conducted tests to determine if Drill Press intercepts could be used to tip off Hawkeye aircraft flying ARDF missions some distance away. Although the Hawkeye could hear the enemy transmissions the signals were not sufficiently strong enough to allow for a positive fix. While these tests were inconclusive, the intercept platform had more than proven its worth. The same was true of the Hawkeye experiments. By February 1966, under a project named ‘Phyllis Ann’, 35 EC-47 airframes were converted to Hawkeye-like AN/ARD-18 ARDF systems.21 At the same time the USAFSS flew in specially adapted AN/TRD-4 DF caravans for use in ground based DF and intercept operations. In April 1966 the 2nd AD became the 7th Air Force (7th AF). Also raised was 6994th Security Squadron with responsibility for ARDF and ACI (Airborne Communications Intelligence – intercept) collection against enemy targets in Vietnam and neighboring regions. The 6994th SS was located at Tan Son Nhut airport and tasked to conduct ARDF and ACI collection against enemy targets in the III CTZ and IV CTZ. (The squadron had three detachments at Phu Cat, Danang and Nakhon Phanom in Thailand giving continuous
20Anon (nd.) Operation Drill Press. Part 1. Genesis and History. On-line. Accessed 27 March 2020 from http://ec47.com/storage/UserFileFolder/Drill_Press_1.pdf 21 The ARD-18 DF equipment utilized a 360 degree antenna configuration which enabled the aircraft to fly on a straight heading and take ‘sideways’ cuts of direction to the enemy transmitter.
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547 Signal Troop and the American Security Agency coverage to the remaining sectors of Vietnam and Laos.) Throughout the war this squadron flew the EC-47 with three different configurations: EC-47N (Phyllis Ann): This aircraft carried the basic AN/ARD-18 (later AN/ALR-34 or 35) DF system. A rod-type DF antenna set in the nose of the aircraft and one in each wing. Inside the fuselage where three consoles: One on the port side for the navigator, one for the X (ARDF) operator in front of the navigator, and another on the starboard side for the Y (documentation and air/ground radio) operator. EC-47P (Drill Press): Similar to the EC-47N but with two additional consoles for the Z1 (linguist) and Z2 (Morse intercept) operators concerned with intercepting voice transmissions. Depending on the mission they could also carry one or two analysts. EC-47Q: This aircraft carried the AN/ALR-38 DF system capable of HF and VHF, a computerized version of the EC-47P DF system. The antenna was blade type with one set on each wing and one in the rear fuselage behind the troop door. In May the first Phyllis Ann aircraft arrived in Vietnam and commenced operations on 6 June 1966 against targets located in Tay Ninh Province. On 29 June, a second Phyllis Ann EC-47 became airborne. With the increased capability the question of ownership of the missions, as opposed to the ownership of the aircraft and crew, began to generate concern. The squadron was administratively controlled by the 6922nd Security Wing at Clark Air Force Base in the Philippines, but was at the same time under operational control of 7th Air Force at Tan Son Nhut airport in Saigon. It was generally agreed, however, that operational control would be exercised by General Joseph McChristian, the USMACV J2.
ASA versus USAFSS These arrangements were not without complications. Two separate organisations were essential to accomplish the ARDF missions: The 7th Air Force’s 460th Technical Research Wing (460th TRW) which provided the platform and the aircraft crew, and 509th RR Gp from whom came the DF and intelligence collection system and operators. Flight instructions (called fragmentary – or ‘frag’ – orders) were issued to the front-end crews which guided them on where and when to go, however these personnel did not have a security clearance to know more than that. Detailed instructions on what to look for, fix and collect was provided to the SIGINT cleared operators. The navigator, while ostensibly part of the front-end crew, had to work very closely with both and therefore had a security clearance sufficient to enable him to understand why the operators were, at times, in control of the aircraft. It was not until 1970 that all crew members were SIGINT indoctrinated. The USAFSS also wanted the ARDF program to be purely tactical, unattached to NSA, and operating in a noncodeword environment. NSA, on the other hand, insisted that it come under direct control of 3rd RRU as outstations of the WHITEBIRCH net. The
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547 Signal Troop and the American Security Agency problem was that USAFSS personnel were not codeword cleared. 3rd RRU was unable to pass technical data to support the AFSS effort until such clearances were arranged. While under of the 7th Air Force (with ‘back end’ crews under command of 6994th SS) the Drill Press aircraft were tasked by 509th RR Gp on weekly assignments to conduct radio intercept as an extension of the tasks conducted by 3rd RRU (which became 175th RR Coy). The aircraft flew daily, initially in the Tay Ninh region and, in early June, over the Central Highlands to Saigon and the Cambodian Border. From around 17 June the Drill Press missions included Phuoc Tuy Province. At the same time as the USAFSS were preparing to launch its operations, the Army was raising the 224th Aviation Battalion (Radio Research) (224thAvn Bn). Under command of 509th RR Gp, the 224thAvn Bn had four subordinate units, each responsible for the ARVN Corps tactical zones of operations. Responsibility for III CTZ was held by 146th Aviation Company (Radio Research) (146thAvn Coy) based at Tan Son Nhut airport in Saigon. The ASA had fifteen light aircraft conducting ARDF mission. They could fly higher and longer, and intercept and locate enemy transmissions without having to fly directly at the transmitter. Because they had this capability the USAFSS EC-47 were tasked with conducting missions over Laos and off the coast of North Vietnam. They were also given responsibility for the mountainous regions of South Vietnam. The remaining sectors of South Vietnam were divided between the USAFSS and the ASA. This delineation of areas of responsibility was predicated on the differences between the two ARDF systems. The USAFSS employed a ‘Pass Measure’ technique which determined the position of the enemy’s transmitter by its direction, (or Line of Position) from the aircraft, while the ASA AN/ARD-15system relied on an ‘Aural Null’ whereby the direction of the enemy is indicated by a ‘null’ in its signal (called the Adcock Effect). While both USAFSS and ASA ARDF operations were successful in identifying the location of enemy transmitters, getting this information to users was problematic. Thus USAFSS DF and intercept tasking was initiated by USMACV J2, 509th RR Gp and 3rd RRU, while the aircraft remained under control of the 7th Air Force. If the 7th Air Force were reluctant to allow the aircraft to fly (due, for example, to weather conditions over the mountains or failure in radar coverage), the ground forces in those areas were denied aerial DF. Thus, the USAFSS, administered out of The Philippines, had control over intelligence gathered over the largest part of South Vietnam, as well as surrounding regions (including Thailand), while the Army had responsibility for whatever was left over. This clearly made it impractical to coordinate all intelligence gathering, and it was not until 1 July that COMUSMACV gained an agreement that an ARDF Coordination Centre would be established in facilities provided by 509th RR Gp at Tan Son Nhut airport in Saigon. Even then intelligence of interest to commanders in the field could be delayed while it wound its way through the maze of reporting agencies and analysis teams.
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For the Task Force this meant that the Australians were at the end of a very long chain of intercept and analysis, even though, as we shall see, such intelligence may have been of vital importance to the survival of the Nui Dat base.
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PART FOUR – ASA AND THE AUSTRALIAN TASK FORCE
In May 1966 the 1st Australian Task Force, a brigade-size formation, commenced deployment to Vietnam. At the time Australia had ten Task Forces (a term used under the Pentropic Division in preference to Brigade), of which only three were full-time. Six of the remaining seven were reserves and the other existed on paper only. The conflict in Malaya and Borneo, along with heightened tensions in Papua New Guinea, continued to stretch the limited human and physical resources available to the Army. It took the introduction of compulsory service in late 1964 to enable the release of two battalions, plus supporting units, to join the 1st Battalion, the Royal Australian Regiment (1 RAR), already in Vietnam under operational control of the 173rd Abn Bde. At the time of the Task Force’s arrival 1 RAR was nearing the end of its deployment and preparing to return to Australia. The battalion had been based at Bien Hoa under operational control of 173rd Abn Bde, but with the increased contribution by the Australians it was agreed that the Task Force should have its own area of responsibility. The province of Phuoc Tuy, south east of Saigon, was identified as the best option and a detailed reconnaissance in force was carried out to clear and secure an appropriate site as the Task Force base. By early June 1966 the Task Force had completed its occupation of the selected site. The incoming infantry and supporting arms soon began to set up defences in a former French rubber plantation close by a small hill 8 kilometres north east of the provincial capital of Ba Rai (Phouc Le). The hill was known by the Vietnamese as Nui Dat, and the Task Force base soon came to be known by this name. The headquarters of the Task Force was located less than 500 metres to the south of the hill, and the men of 547 Sig Tp were allocated an area close by.
547 Sig Tp arrives in country The main body of the Troop arrived in Vietnam on 13 June 1966. After a detour to Vung Tau to marry up with the advanced guard and collect the Troop’s stores and equipment, the men made their way to Nui Dat the following day. Under an agreement reached between the US and Australian authorities, 547 Sig Tp was deployed as the DSU to the Task Force and were initially allocated an area near to the headquarters. But this was found to be too small – and too insecure – so another was sought. An area next to the Task Force signal squadron was later identified where the
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Troop could build a secure compound and erect the antennae necessary to commence operations. With slight modifications – particularly in the equipment used – 547 Sig Tp performed similar tasks to other DSUs. Aside from specialist teletype operators, clerks and technicians, all members of 547 Sig Tp were primarily from the Operator Signals trade, trained to intercept both Morse and voice communications. While not specifically trained to do so they also carried out basic analysis of enemy communications, in particular ‘finger–printing’22 VC and NVA transmissions in order to maintain continuity when the enemy frequencies and callsigns were changed. It also enabled them to provide a more detailed picture of their intercept prior to passing to analysts from the Australian Intelligence Corps. On arrival many operators were also trained in either MRDF/SRDF or ARDF so that, where necessary, they could with limited preparation undertake a DF task employing either the ground or air-based direction finding equipment organic to the Troop. Where necessary the operators could also be tasked with operating teletype links from fixed or mobile bases utilising a specially configured M577 Armoured Personnel Carrier (APC) with operators performing all functions. Other teams deployed on intercept or DF tasks in open unarmed Land Rovers or on foot with infantry or Special Air Service. Linguists were also attached to the Troop for more detailed translations. Because the area of operations covered by most Task Force operations were well within radio communications range, the Troop rarely deployed outside the wire prior to 1969. The most significant exception was the rotating three-man detachment flown in to support the Task Force operation at Fire Support Base Coral during the 1968 Tet operations. Morse operators and a linguist were deployed with the Task Force (Forward) headquarters to search and record any low level enemy communications. Officers from the Troop also flew into FSB Coral each morning to brief commanders on the latest intelligence on the enemy positions and intentions. During the war the Troop, aside from providing direct support to the Task Force, also provided support to US units operating within or adjacent to the Phuoc Tuy area of operations. Direct and indirect support was provided to the 199th Light Infantry Brigade (199 LIB), 173rd Abn Bde, 3rd Brigade of the 1stArmoured Division, 25th Infantry Division (Tropic Lightning) in particular the 2nd Brigade under Colonel Ulatoski who later wrote a commendation for the Troop (see page 78), and the 9th Infantry Division during, amongst others, Operation PADDINGTON (10-16 July 1967). Another major American unit the Troop gave support to was the 11thArmoured Cavalry Regiment whose commander, Colonel (later Major General) George S Patton (son
22 ‘As well as being able to identify a VC or NVA station by the characteristics of the radio used (eg, emitting a scratchy or ‘squawking’ signal, being unable to hold a frequency etc), the operators were also skilled at identifying individual operators by the way they sent Morse codes or replied when chatting with other operators.
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547 Signal Troop and the American Security Agency of the legendary World War II commander) caused a great deal of interest when he visited the Troop in May 1968. As confidence in the Troop grew, and the Task Force concept of operations shifted towards greater aggression at the edges of the TAOR, small detachments were regularly deployed to Fire Support Bases and Forward Operating Bases in support of Australian and US operations. One intelligence officer is reported as saying that when the ground forces were not in contact with the enemy, very often the only contact The Task Force had was through 547 Sig Tp.23 For their action during the fighting at FSBs Coral and Balmoral, the Troop was recommended for and received the Australian Unit Gallantry Citation. They were also awarded the RVN Gallantry Cross with Palm Unit Citation and recommended twice for US and Australian meritorious citations.
DSU to the Task Force Unlike other ASA Direct Support Units, at the time of its arrival in Vietnam 547 Sig Tp did not have an organic DF capability. It was not envisaged that the Troop would require such a capability as the deployment orders stated that all it would be doing was acting as a conduit for intelligence from II FFV, and conducting intercepts as time and opportunity permitted. Nor was it something that was practiced during exercises back in Australia. Where there was a requirement for DF this was generally in support of a wider operation, for example tracking a foreign vessel off the coast. This required a series of fixed DF stations working in unison to triangulate the target, and for Army this was not a regular task. However shortly after the Troop commenced intercept operations in Vietnam a number of VC units operating in and around the Task Force’s area of operations were identified, and tracking their locations became a number one priority for the Troop and 175th RR Coy. The importance of possessing the ability to not only listen to but also locate enemy transmitters became very clear soon after the Troop’s arrival. The first major challenge was against a Viet Cong callsign that the Australians came to know as Dodo.
Dodo Within days of its arrival the Troop was copying an unidentified Viet Cong radio station sending traffic at a slow and careful speed. The VC unit was using a low level cipher system enabling most of the message to be quickly deciphered and read. The station, nicknamed Dodo, was known to 509th RR Gp who gave the transmitting station the ‘identifier’ of RAD 196B and listed it as VNGB (Vietnamese Guerrilla Morse) M7178.
23 Tidey, B. (2007) Forewarned forearmed: Australian specialist intelligence support in South Vietnam, 1966-1971. Issue 160 of Canberra papers on strategy and defence. Strategic and Defence Studies Centre, ANU. Canberra. P. 45.
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Previous intercepts had learned that this station was the headquarters of a VC intelligence unit reporting on vehicular traffic moving along Route 15. When the messages were decoded it was found that they were being sent to the headquarters of the VC’s 5th Light Infantry Division, at the time located in the north-east of Phuoc Tuy province. It was suspected that the VC had established observation posts in the hills overlooking Route 15, and that reports on the road traffic were being delivered by courier to the intelligence unit’s headquarters for encoding and transmission to the 5th Division. The station was first identified by operators at 509th RR Gp and 303rd RR Bn, but the distance was too great for the signals to be read clearly. Intercepts undertaken by these stations were reported as ‘of such poor quality that corrupt text was causing extensive loss of valuable intelligence’.24 In June, a USAFSS EC-47 Dakota aircraft from the recently raised 6994th SS was sent out to find the enemy transmitter. The operators on board this World War II vintage aircraft located the transmissions as coming from a thickly vegetated area in the low ground between the most prominent features of Nui Dinh and the Nui Long Trinh, some 12 kilometres to the west of Nui Dat (see maps on Page 57). From then until 27 July aircraft from 6994th SS were dedicated to supporting operations against Dodo and another station called Leech located in the Nui Thi Vai hills (RAD 255A listed as VNGB M7191), later suspected to be elements of the VC 274th Regiment (274 Regt). As noted above, the Squadron employed EC-47 aircraft in two configurations giving the USAFSS the capability to conduct aerial (or airborne) radio direction finding (ARDF) operations (Phyllis Ann) and radio intercept (Drill Press). Employing Drill Press aircraft configured for high frequency (HF) and very high frequency (VHF) Morse code and voice intercept, the squadron was able to more clearly read the enemy transmissions. These were later described by the commander of 175th RR Coy as providing an estimated 75 percent of the company’s usable intelligence.25 With 547 Sig Tp now operational and directing DF operations, confidence increased in the quality of intercepts and the main effort against the VC stations was picked up by the Australian operators at Nui Dat. The terrain between Nui Dat and the Nui Dinhs was flat and open, and the VC radio signals were being heard loud and clear by the operators at 547 Sig Tp. Most had several years’ experience intercepting Morse and voice radio transmissions during previous operational service in Malaya and Borneo, and therefore had little difficulty copying this station. Unknown to the VC, the messages captured by the Troop were also being deciphered and read. They were encoded in a low grade cipher that was easily broken leading to a discussion concerning whether to allow the station to continue transmitting and thereby reveal more about the VC codes and ciphers, or mount an operation to find and eradicate the enemy unit.
24 History of the 6994th Security Squadron. 1 July-31 December 1966. P. 26. 25 Op cit p. 26
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To the Americans the answer was obvious. Route 15 was a critical main supply route carrying road traffic from the port of Vung Tau to Bien Hoa and Saigon. Prior to the American build up US ground troops and the arrival of the Australian Task Force in 1966 the ARVN had suffered many casualties from ambushes along the highway. The possibility that further observation of the road traffic by the VC might increase the chances of more convoys being ambushed won out and in early July General Westmoreland instructed the Australian Task Force to find and destroy the observation posts in the hills overlooking the last known location of the VC unit. 509th RR Gp was ordered to provide ‘maximum support’ to the operation. The main support required by the Troop was the means to identify the location of the enemy in order to direct ground operations against them. However, successive ‘cuts’ by the US ARDF were creating confusion. Reports from the aircraft indicated that either the VC headquarters was moving positions frequently, and over long distances, or the AN/ARD-18 direction finding equipment employed in the aircraft was not sufficiently accurate to allow for confidence to be held in the results. Previous experience with the US ARDF suggested that a more accurate means for locating the enemy transmitter was needed if General Westmoreland’s orders were to be complied with. The commander of the 509th RR Gp agreed and instructed ground based short range direction finding (SRDF) teams to be prepared to deploy to Nui Dat. The first of these, a seven man team from the 372nd Radio Research Company (372nd RR Coy) at Cu Chi, arrived on 17 July and commenced operations the following day employing the AN/PRD-1 DF working in conjunction with the USAFSS aircraft to triangulate the enemy location. On 16th July, the day prior to the SRDF team’s arrival, the Task Force deployed the 6th Battalion of the Royal Australian Regiment (6 RAR) by Armoured Personnel Carrier to an area south of the last known location of the enemy transmitter. They took with them three days’ rations and, supported by artillery from the New Zealand 161 Battery, were under orders to seek out and destroy the enemy.26 Four teams from the Australian Special Air Service (SAS) were also instructed to move with the battalion. Once the battalion and its supporting forces were on the ground, the SAS were to depart the 6 RAR position shortly before last light and conduct patrols in the hills northwest of the provincial capital of Baria in order to interdict any enemy forces withdrawing before the Australians. The infantry and, at least initially, the SAS, were not aware that 547 Sig Tp was monitoring the enemy transmissions or that, through ARDF, the Troop was aware of the VC’s approximate location. And, even if the Troop was aware that 274 Regt was also located in and around Nui Toc Tien to the north of 6 RAR’s location, this was not something that they could share with the infantry on the ground. As a result, neither the infantry nor the SAS patrolled into the area where Dodo had been last located by 6994th
26 This was known as Task Force Operation BRISBANE conducted over the period 16-1 8 July 1966 in response to intelligence reports concerning proposed VC ambush of road convoys on Route 15.
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Squadron, On 18 July the infantry withdrew and returned to Nui Dat while the SAS continued patrolling the area searching for the enemy. Throughout this period Dodo remained on the air. Fixes on the station’s location continued to be provided by 6994th SS and now by the team from 372nd RR Coy, both showing wide variations – sometimes up to 6 kilometres. The SAS patrols were tasked with covering as much of the area as they could within the restraints of time and physical resources, however while they found signs of recent activity they had few contacts with the enemy. Communications with the Task Force were also problematic, and this reduced the effectiveness of the SAS patrols. The communications problems were only improved when a relay station was set up at Vung Tau and the patrol’s A510 wireless sets were replaced with the newer AN/PRC-25 sets. With 6 RAR’s return to Nui Dat the task of the SAS patrols was extended with the objective to destroy the observation posts and the radio station. The fixes from ARDF and SRDF remained much the same as they had over the previous few days, and for four days SAS patrols swept the area in which the VC station was reported as being located, but again with little success. On 22 July the DF teams picked up that the station had moved, but by now the remaining SAS patrols were running low on food. They were instructed to continue their search while fresh patrols were prepared for insertion. The next day they were informed that the VC had moved again, and once more the SAS were told to maintain their patrolling until relieved by fresh patrols. It was apparent that the VC were aware of the Australian patrols and moving their headquarters in order to avoid contact. To protect their withdrawal they began to aggressively pursue the SAS. Airstrikes on known or suspected enemy positions had limited effect so the most seriously compromised patrols were withdrawn and returned to Nui Dat while fresh patrols were inserted to continue the search. Meanwhile, on 23 July the officer commanding the SAS unit, Major John Murphy, was called to Saigon to brief General Westmoreland and his staff on progress of the operation. On 31 July, the team from 372nd RR Coy returned to Cu Chi and was replaced on 3 August by a four-man team from 337th Radio Research Company. This team set themselves up at the ARVN basic training compound at Van Kiep near Baria, five kilometers from Nui Dat. Members of 547 Sig Tp travelled down to Baria to learn the fundamentals of the AN/PRD-1. Consideration was given to borrowing one or more of these to enable the Troop to carry out its own SRDF, but as later events showed, the introduction of a more accurate and reliable ARDF capability organic to the Troop negated the need for the ground based DF equipment. So, for the time being at least, the Troop had to rely on the teams dispatched to Nui Dat for SRDF missions.27
27 The OC of 547 Sig Tp, Captain Trevor Richards, and the COMD 1 ATF, Brigadier Hughes, agreed that for the Troop to have PRD-1 capability there would be a need for at least a company of infantry to be deployed to provide security on occasions when the DF team needs to be located further afield in order to triangulate an enemy transmitter. This, it was agreed, was neither feasible nor warranted.
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The team from the 337th RR Coy continued to provide SRDF support until 14 August when an air mobile, or ‘fly away’, team from 303rd RR Bn arrived. The team was selected from ASA soldiers yet to be allotted to a field unit, and were instructed to travel by utility landing craft (LCU) down the Mekong River to Vung Tau and then by road convoy to Nui Dat. They were to take with them four jeeps with trailers, four AN/VREC- 47 radio sets, and four KY-8 speech ciphony (voice encryption) devices. They were also to take four jeep mounted AN/PRD-1 DF sets. Under the command of Lieutenant John Floyd Cochrane of Dearborn Michigan, this team arrived at Nui Dat on 14 August. They were directed to focus their main effort on Dodo, but while in location to also provide DF support to other targets identified by 175th RR Coy as second priority. With Lieutenant Cochrane were a sergeant and twelve operators, broken into four teams. One team was sited at the airfield at the ARVN compound at Van Kiep near Baria and another on the high ground from which the base at Nui Dat took its name (and later known as SAS Hill). A third team could not initially be employed as there was a lack of secure base from which to operate, however on 17 August it was sent to Binh Ba five kilometers north of Nui Dat under protection of a company of infantry supported by Vietnamese local force militia. That night the Task Force base came under mortar and rocket attack, and a rumour was picked up that this group was also to be mortared so they were relocated to Hoa Long shortly afterwards. The fourth team set itself up alongside the Troop’s operations centre. When the VC radio station named Dodo came on the air the frequency and callsigns were passed to Lieutenant Cochrane’s teams who immediately began taking fixes on the transmitter’s location. The team’s radio system was set up so that as the enemy operator was transmitting, the signal was relayed over the AN/VREC-47 and KY-8 allowing the DF operator to hear the target themselves before picking it up on the AN/PRD-1, however this was not entirely necessary as the US soldiers were DF, not Morse, operators. With a distance of 5-7 kilometres between each team, the bearings from each resulted in a ‘fairly Figure 13 . AN/PRD-1 in action in the accurate’ triangulation of the enemy transmitter. ‘Fairly field. Source unknown. accurate’ because the AN/PRD-1 was designed as a short-range direction finder meaning that the greater the distance to the enemy transmitter the less confidence could be held in the readings. Despite this, the AN/PRD-1 teams were able to give a more accurate report on the enemy location than the ARDF. The SRDF teams regularly placed Dodo in the vicinity of grid squares YS3666 to YS3766, whereas the ARDF consistently placed them up to three kilometers in either direction (see map on page 57). In an attempt to obtain a more accurate
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547 Signal Troop and the American Security Agency fix on the transmitter’s position, on 22 August the SRDF team enlisted the assistance of three of the PRD-1 teams then in the field with 173rd Abn Bde.
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This six-team operation proved ineffective because of the distance between the 173rd Abn Bde teams and the target. Frustratingly, this also meant that additional SAS patrols sent into the area to confirm the DF results returned to Nui Dat reporting no sign of the enemy. Nevertheless, more confidence was given to the SRDF fixes and on 24 August 1966 an SAS patrol was inserted into the area to locate the enemy and, if possible, capture or destroy the enemy radio installation. During the period the SAS were searching the hills, successive SRDF fixes identified the transmitter as within 500 metres of the Australian patrols. The men from the SAS patrolled for five days without making any contact until late on 29 August when they came across what they reported as 40 VC at a base camp at YS362659. The men determined that they had insufficient firepower to engage the enemy and attempted to withdraw but were spotted and fired on by a roving VC patrol. One VC was killed and for the next seven hours the patrol and the VC played cat and mouse until the Australians could be picked up by helicopter under the cover of US gunships. On 31 August SRDF identified Dodo as transmitting from around the same location as the VC camp discovered by the SAS two days’ prior. The station came up at the usual time of 0230Z (0930hrs local time) and was fixed at YS361659 by the SRDF team, however there was no sign of him during his scheduled 0900Z (1630hrs local time) transmission. On 1 September an air strike was called onto that area. High explosives and napalm were dropped by US Aircraft. The results of this air strike are unknown as the SAS, having been warned out to prepare to support a joint operation being conducted in the east of the province, were unavailable. Two days later the ‘fly away’ team was also instructed to shift its focus to supporting the larger operation underway in the north and east of Phuoc Tuy. It was later noted that despite the SAS thoroughly searching the area in which the AN/PRD-1 fixes consistently placed the enemy transmitter; no trace was found. However, a more intensive search and destroy operation conducted in the same area on 13 September found an antenna sticking above the jungle canopy. An air strike was carried out with a follow up sweep the following day, but while the antenna and other equipment were found there was nothing else to identify the station at that location. Despite the failure by the SAS to locate the enemy transmitter, the results of the ‘fly away’ team were more accurate than was accepted at the time by the Task Force headquarters. Dodo was eventually found by 6 RAR on 24 October during patrols inserted into the Nui Dinhs specifically to clear the area of enemy activity. A camp at YS329656 identified by earlier patrols was revisited and, upon arrival, the Australians engaged a small group of VC who scattered into the undergrowth. While clearing the area a soldier noticed a radio antenna hanging from a tree with a long wire leading into a cave. The cave was searched and a radio found, along with a woman attempting to hide by clinging to the roof. It was later learned that her
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547 Signal Troop and the American Security Agency name was Tô Thị Nâu (aka Minh Hoang), a 23-year-old member of the National Liberation Front (NLF) Proselytising Committee28 at Hoa Long, two kilometers from Nui Dat. It was she who had been transmitting the messages heard by the men of 547 Sig Tp and fixed by the ARDF and SRDF teams. From then on she was referred to as Madam Dodo.
Figure 14. Members of 6RAR with captured VC radio operator outside cave in Nui Dinh hills. Source: Australian War Memorial. SIGINT and the battle at Long Tan As noted above, the Troop’s deployment order specifically stated that its primary function was to act as a conduit for intelligence from US sources. However, the tempo of operations during the Task Force’s early months meant that the value of the intelligence passed by the Troop to the Task Force headquarters degraded exponentially the longer it took to reach those capable of acting on it. It was clear to the Troop, and DMI, that the Australians must get on the front foot when it came to generating intelligence of value to the Task Force or risk being caught unprepared. The importance of doing so was demonstrated in August 1966 when the credibility of the intelligence gained in the days and weeks before the fighting in the rubber plantation at Long Tan was challenged for reasons that to this day are still unfathomable.
28 A Proselytising Committee was a group formed to spread propaganda and recruit new members to the VC cause.
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Throughout late July and early August 1966, the Task Force had been receiving warnings of a potential major enemy offensive in the Australian area of operations. These warnings came from civilians and South Vietnamese security personnel who claimed to observe up to several hundred armed men and women moving about the province. Although well meaning, the information brought to the Task Force from local militia or civilian authorities in the village was often given less credibility than any other, not just by the Australians but by the Americans as well. The Australians also regularly received information concerning enemy movements throughout the province from their South Vietnamese colleagues, the ARVN. But, like the information received from civilian agencies, there was concern over the reliability of the intelligence gathered by these means. Reliability, in this sense, meaning not only accuracy of the information but the timeliness of its analysis and receipt. At Figure 15 is an example of the delays experienced in the passage of intelligence which might be of interest to the commander on the ground. Unusually (as these were not normally included in the Ops Log) this is a message concerning an intercept received by an RVN Air Force SIGINT aircraft reporting on an intercepted message indicating the VC intention to attack a US formation. It was received at 0921 on 5 July but not assessed until 1630 – over seven hours later. And, although well outside the Task Forces area of operations, it was not received by this headquarters until 2100 – twelve hours after the original intercept.
Figure 15. Extract from the 1 ATF Ops Log for 5 July 1966. The majority of credible intelligence about the locations and intentions of the VC therefore came from US ARDF missions, yet it too was subject to delays rendering the intelligence of lesser value. According to the War Diaries of the period, many of the ARDF reports, generated by II FFV, were received by the Task Force in the early hours of the morning. It is likely that these may have been read by the Duty Officer (if cleared to do so), but unless the Intelligence Cell was working past midnight, the Special Agent Reports containing this information would not have been subject to close analysis for up to 24 hours after the enemy locations were identified. Experience had shown the Task Force commander that previous patrols acting on similar information often returned empty-handed therefore he and his senior staff were reluctant to move on anything but the firmest of intelligence. This is not to say that all ARDF reports of interest to the Task Force were subject to such lengthy delay. SPAR reports received by the Task Force at 0100 or 0200 in the morning may have been gained by aircraft from the US Air Force’s 6994th SS conducting night operations (which the squadron was experimenting with at the
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547 Signal Troop and the American Security Agency time). Nevertheless, even with the ARDFCC working well into the night (in later years the Centre worked 24 hours), unless there was some indication that the intelligence was urgent, the SPARS would most likely not be read until some six or seven hours later. In order to understand how this impacted on the confidence shown in SIGINT by the Task Force commander it is important to consider that ARDF had never been employed before by the Australian forces. More importantly, it was also a relatively new capability to the American forces which, themselves, were grappling with the issue of accuracy and timeliness, not to mention coordination and release. This meant that unless the analysts were looking for specific information in the ARDF results there was always going to be delays before their importance could be realised and passed to the allied unit in the best position to respond.
Side-stepping official channels Since their arrival American ARDF flights had been tracking enemy forces to the south and south east of Saigon, with particular attention being paid to the area around the Nui Thi Vai and Nui Dinh hills. In early August an EC-47 Phyillis Ann (DF) aircraft was flying in support of Operation HOLSWORTHY, a cordon and search operation undertaken by 5 RAR at the village of Binh Ba scheduled to commence on 7 August 1966. The ARDF team identified the transmitter of the VC 275th Regiment (275 Regt) to the east of the Task Force. An analysis of previous intercepts of this unit, and its sister regiment 274 Regt, determined that up to this time they had been resting and refitting therefore confirmation of their location held no significant priority for action. Nevertheless, both 274 and 275 Regiments were of interest to the US and Australian commanders. The last reports concerning 274 Regt identified it as widely dispersed across the northern regions of Phuoc Tuy and eastern areas of Bien Hoa. Reports of large numbers of enemy troops in the Nui Dinh region were also received but, beyond the intelligence units reporting on Route 15, and a sub-unit of 274 Regt (code named Leech), their identity at the time was not known. Of greatest interest to the Task Force was 275 Regt which was located to the west of the May Tao mountains at YS515708. At the same time the Drill Press (intercept) aircraft from 6994th SS were copying the 5th Division transmissions for analysis by 175th RR Coy, the operators at 547 Sig Tp were also intercepting these signals. Both 274 and 275 Regiments were reporting on regular schedules with their headquarters, the 5th VC Division, further to the east in the vicinity of YS646821. They appeared to be sending routine traffic. From late July, however, the intercept operators at 547 Sig Tp noticed that the messages were becoming more frequent and longer, and in early August there appeared a sudden increase in radio traffic. Like 175th RR Coy, the Troop analysts concluded that the 274 and 275 Regiments, along with the 5th Division’s ancillary forces, were preparing for a major operation. Of greater concern was the fact that,
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547 Signal Troop and the American Security Agency from 2 August the Phyllis Ann ARDF operators were reporting the radio transmissions as coming from locations progressively getting closer to Nui Dat, suggesting that whatever the enemy was up to, it would require a response from the Task Force. It was clear that the Task Force commander had to be briefed on this new development. The problem, however, was that the secrecy surrounding the Troop and its intelligence role meant that there were few on the Task Force headquarters who could receive this information. The Intelligence Cell could receive and read the SPAR reports because they originated from the Americans (including intercepts captured by the Troop), but there was no precedent for consideration of SIGINT generated from within the Task Force itself. Besides, of those who could be briefed none had significant experience at using SIGINT. As a result the warnings offered by the Troop were not taken with a degree of seriousness that showed an awareness of the intelligence’s value. It was only after the defeat and withdrawal of the enemy forces after Long Tan, and the analysis of all available intelligence prior to Operation TOLEDO (see below), that the value became clear. Afterwards the Task Force commander was heard stating that he would never again ignore the intelligence that the Troop collected. The commander’s first opportunity to adhere to this commitment came in September and October 1966 when support to the Task Force was again received from EC-47 Dakota aircraft from the USAFSS 6994th SS. The aircraft were undertaking airborne radio intercept, in support of Operations BATHURST (6 RAR TAOR patrols 20-27 October) and QUEANBEYAN (5 RAR 17-26 October). 5 RAR had been deployed against 274 Regt now in the Nui Thi Vi region of Phuoc Tuy and who, it was believed, were again planning attacks against convoys on Route 15. The EC-47 achieved over 35 DF fixes on the enemy positions, most of which were sufficiently accurate to pass to 547 Sig Tp and the Task Force headquarters which, in turn, used this information in directing the infantry in the field. Despite limited results on the ground, the deployment of 6 RAR in response to the ARDF reports showed increasing confidence in the Troop and its analysis of the intelligence being gathered by the men and their American colleagues. Such confidence soon enabled the commander to deploy his limited combat forces against a threat that could have had dire consequences for the fledgling Task Force and the Australian presence in Vietnam. Operation TOLEDO After 3 September the primary mission of the ‘fly away’ SRDF team, collocated with the Troop since August, changed to providing support to the 404th Radio Research Detachment (404th RRU), the DSU for 173rd Abn Bde. At the time the 404th RRU was, like 547 Sig Tp, operating from a firm base at Bien Hoa and deployed 2-3 man detachments with each of the Brigade’s battalion. The ‘fly away’ team was tasked to
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547 Signal Troop and the American Security Agency make up the shortfall in DF support to the Brigade headquarters while these detachments were deployed. They ‘fly away’ team joined the 173rd Abn Bde SIGINT network as it was preparing for Operation TOLEDO, a joint force operation conducted between 10 August and 7 September in the north and east of Phuoc Tuy Province. This operation was initiated by II FFV to follow up the success of Operation SMITHFIELD (19-22 August immediately after the fighting at Long Tan). The concept of the operation was that 173rd Abn Bde, with under control US Marines and ARVN Rangers, would sweep east from Bien Hoa to the southeast of Xuan Loc and south of Gia Ray and seek out and destroy the enemy forces along this line. Their objective was the 5th Div headquarters and sub-units identified as being in the May Tao Secret Zone some 20 kilometres to the north east of the Task Force. As well as locating and fixing the headquarters of the VC 5th Div, ARDF identified the headquarters of 275 Regt as being further up into the May Tao mountains in the vicinity of grid squares YS5473. A Local Force Battalion, the 860th, (860th LF Bn) was also known to be part of the 5th Div but at this time its location was unknown. ARDF also continued to identify the headquarters of 274 Regt as being well outside the Task Force area of responsibility, but with sub-units between the Nui Thi Vai and Nui Dinh hills (YS 2871 – YS 3364) to the west of Nui Dat. After their mauling at Long Tan, it was clear that the VC 5th Div had chosen to scatter its forces, with the headquarters of 274 Regt returning over 13 kilometres to the Hat Dich Secret Zone in the west of the province, leaving reinforced sub-units to threaten 5 RAR which was conducting pacification operations at Binh Ba. The objective of the Australian Task Force was to establish a screen on a north-south line parallel to Route 2, and deploy infantry and armour, supported by artillery, against 274 Regt to the west of that line. The target of the SRDF team was 275 Regt against which the Task Force deployed SAS patrols to track and observe their movements. This was the first operation in which the Task Force commander placed confidence in SIGINT and, in particular, the results of the ARDF and SRDF missions. Basing his operational plan on the intelligence gained from the Troop and supporting ARDF flights, the Task Force commander took a gamble and deployed his forces to actively pursue and engage the most immediate threat to the north and west while maintaining a close watch on the potential threat to the east. It was here that the Troop became actively engaged in the operation. Because it had been located furthest from the Task Force at Nui Dat, the 275 Regt was judged to be the lesser threat, so the two infantry battalions, 5 RAR and 6 RAR, were deployed to the north and west of the Task Force to deal with any threat from 274 Regt while, at the same time, blocking any potential withdrawal by 275 Regt. With the Americans and ARVN pressing the VC from the north and east, he positioned SAS patrols as screens to the east of Nui Dat to observe and track the movements of 275 Regt. To support this operation the SRDF team was given as its
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547 Signal Troop and the American Security Agency primary target 275 Regt (RAD 136C – VNGB M7157) which it located on 4 September at YS558655. The SAS found multiple signs of enemy presence, some only days old, but experienced few contacts. Meanwhile, the SRDF team at Nui Dat continued to take regular bearings on the 275 Regt transmissions which the Troop reported to the Task Force as a guide to tasking the SAS patrols. On 6 September a patrol was tasked to observe an artillery mission called on the suspected location of 275 Regt at YS508655, 2,000 metres to the east of Long Tan. The patrol heard voices and a transistor radio at YS509653. Signs were found of recent activity of up to approximately ten VC but no evidence of casualties or damage from the artillery. Mid afternoon the next day an SAS patrol came across a recently vacated camp with tracks indicating that the VC were moving to the south east of the Task Force. After this nothing further was heard of the regiment until 8 September when they were fixed some 5,000 metres to the south east of Nui Dat at YS438617. The following day the SRDF again fixed 275 Regt, this time at YS439618 and a composite troop from the SAS squadron was immediately deployed to the area. The next day as they approached the area where 275 Regt headquarters had been identified the patrol heard warning shots and observed a group of about 10 VC fleeing to the north east. A standby force was flown into blocking positions and a sweep made of the area but without result. At 1800hrs both groups returned to Nui Dat by M113 APC. RAD 136C was not heard again until the afternoon of 10 September at which time the SRDF team fixed them at YS458655, around 2000 metres north east of their last location, and less than 2000 metres from the Nui Dat base. This distance was far closer than the enemy forces had been during the Battle of Long Tan, and naturally the Task Force commander was concerned. In a briefing to the Task Force commander the Troop OC acknowledged that it was impossible to tell whether the enemy unit was moving towards the Task Force or away from it. It was most likely, however, that the target was of no larger size than a headquarters element attempting to make its way to safety while avoiding the friendly forces. The fact that the SAS had not identified any large bodies of troops convinced the commander that this group posed little threat to the Australian base. Focus therefore returned to the Nui Dinh hills where large enemy concentrations had been reported massing. The Task Force was instructed to re-enter the hills with a view to finding and destroying these forces. It was during this operation that Madam Dodo was captured and nothing more was heard from this station. The first confirmed ‘fix’ on the 5th Division was on the same day. An EC-47 located the headquarters of the VC 5th Division in grid square YS6779 on the eastern most region of the province. Although the ARDF and SRDF fixes on this headquarters varied widely, sometimes up to six thousands metres apart, an analysis of the location
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547 Signal Troop and the American Security Agency of the 5th Division headquarters and its sub units suggested little threat to the Task Force. Even with the variations in DF results, sufficient confidence was beginning to be held in the DF reports and the briefings received from 547 Sig Tp. The after action report from 173rd Abn Bde stated that SRDF and ARDF were largely responsible for the success of Operation TOLEDO. Although not specifically recorded in the official reports from the Task Force, it was clear that SRDF also played a significant role in tracking the movements of 275 Regt, and enabling the commander to gain sufficient confidence in the intelligence to deploy his forces in order to meet, and defeat, the most credible threats posed by the enemy. Successive Task Force commanders would show similar confidence in the intelligence captured by the Troop, with the result that information provided by the Troop on enemy locations and strengths would be relied on during most future operational planning.
Special Forces pick up the DF task After the unsuccessful attempts to find and eliminate Dodo, by 28 July the last of the SAS patrols had been withdrawn from the Nui Dinhs. Aside from some minor contacts with the VC and numerous sightings of the enemy’s presence, the patrols had not been able to find the enemy headquarters or bring any of its elements to contact. Moreover, results of the SAS patrols were often held over until they returned to Nui Dat, meaning that delays of up to a week would be experienced before the accuracy or otherwise of the fixes could be confirmed. As noted previously, throughout this period the AN/PRD-1 fixes were found to be relatively accurate, and the ARDF reports showed variances of up to six kilometers thus calling into question the reliability of all DF results. What was required was a means for both getting close enough to the enemy position to accurately identify their location, and to call in ground forces to attack them with little delay. Ideally, what was needed was the means to shorten the gap between getting a firm fix on the enemy transmitter, and having ground forces close with these forces as soon as their position was confirmed. It also meant employing a DF capability that was portable, concealable, and more importantly, accurate. After their defeat in August and September 1966 the major VC units began relocating outside of the Task Force area of operations. Intercepts, supported by SRDF and ARDF reports, showed these units progressively moving away from the Task Force and the requirement for ground based DF stations ceased. After four weeks the ‘fly away’ team closed down and returned to Saigon.29
29 The commander of this team, First Lieutenant Cochrane, was killed one month later when the jeep he was travelling in was disabled by an enemy sniper, who then shot the officer. Cochrane was married and due to meet his wife six days later in Hawaii.
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About this time, it came to the attention of the officer commanding 547 Sig Tp that the 303rd RR Bn was trialing a newer and more accurate DF capability, the Telefunken PE-484 miniature direction finder. The PE-484 was a German made portable DF set that could be carried by an operator on the move wearing a concealable antenna or set up on a tripod with a larger loop antenna. In order to locate an enemy transmitter an operator would tune the DF receiver into the required frequency and, listening to the transmission through a set of headphones, move his body from side to side while wearing the concealable loop antenna, or rotate the fixed antenna on top of the receiver until a nul occurred in the signal. The direction was then noted and a ‘cut’ recorded. By moving to another position the operator was able to take further ‘cuts’ and thereby triangulate the enemy transmitter’s position. During Operation TOLEDO, consideration had been given to training SAS signalers to undertake radio direction finding whilst on patrol, an ideal target upon which to conduct such an experiment being Dodo who continued to be active in the hills above Nui Dat. The Americans already had such a capability with the newly arrived 403rd Special Operations Detachment (Radio Research) (403rd SOD) based at Nha Trang and providing DSU to 5th Special Forces Group (5th SFG). In order to test the feasibility of using US and/or Figure 16. Telefunken PE-484 portable radio Australian Special Forces to undertake such direction finder on tripod. Source unknown tasks, four non-commissioned officers from Nha Trang were flown to Nui Dat with instructions to accompany Australian SAS troops on patrol during which the DF equipment would be tested. In exchange, four Australian SAS soldiers were sent to Nha Trang. The Operations Log of the SAS 3 Squadron notes the unit being warned of the arrival of four members of Special Forces Project DELTA on 11 September 1966, their arrival scheduled for the following day. The combined SAS and USSF patrols were tasked with re-entering the area where Dodo was last located with a view to employing ground based DF to take bearings on the transmitter when it next came on the air. The results of these tests are unknown, but from the fact that SAS patrols were never factored into the SIGINT DF effort it would appear that they were not a success. It would be another 2-3 years before these tests were repeated, this time however operators from 547 Sig Tp would take the equipment into the field in support of major operations, either working in teams of 2-3 or as part of an SAS patrol. Despite the failure of these tests, the SAS were critical in providing collaborative evidence to support ARDF fixes, and for the remainder of the war 547
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Sig Tp intercepts would be the basis for many of the SAS patrols within the Task Force area of operations.30 An example of such cooperation occurred in June 1968 with the SAS capturing an enemy radio located in the Nui Dinhs.
D445 On 30 May 1968 the SAS were briefed on an operation to locate and eliminate a Rear Services Group from the VC 445th Provincial Mobile Battalion (D445 for short) operating in the vicinity of the camp where Madam Dodo had been captured the previous year (see map page 57). The men were informed that they had reliable information on the location of the D445 headquarters through its radio transmissions but were not told the source. The patrol was inserted by helicopter on the eastern slope of the Nui Dinhs at 0730 on 8 June and immediately set out along a steep spur for the suspected enemy camp above them. For the remainder of the day they struggled up the rocky slope, crawling over large boulders and fighting their way through tangled vines (see picture on Page 58). The next day they heard voices close by to their south west and crawled into a hide from which they were able to identify the enemy location. Here they remained listening to the sounds indicating that the enemy camp was nearby. On 10 May the men could still hear the VC so they worked their way further up the slope until they were overlooking the enemy camp. At 1300 the men were finally able to observe the enemy moving around less than 100 metres below. They had initially thought to lay up observing the VC for the day but decided that the risk was too great. After a quick whispered discussion the men moved into position and began to bring machine gun and rifle fire to bear down on the unsuspecting enemy. Within minutes at least six VC lay dead. Grenades and M79 rounds lobbed into caves and dead ground around the camp indicated that more enemy was hiding there. With half of the patrol providing covering fire the remainder pushed forward into the camp, killing more of the enemy and sending the rest fleeing down the slope. During a lull in the firing the commander of the patrol noticed a radio sitting on a table in the middle of the camp. He quickly picked it up and stuffed as many documents down the front of his shirt as he could before withdrawing. The patrol could only guess at the number of VC killed, but more importantly they had captured the radio along with a substantial quantity of important documents. The radio was home made, but was clearly the one the men had been seeking. The action took less than ten minutes but resulted in a massive blow to the enemy who lost not only a number of important documents but also a vital radio.31
30 In 1970/71 the Troop conducted similar operations with the SAS with little success. On each occasion a Morse operator accompanied the patrol but atmospherics and humid conditions rendered the equipment unusable.
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DET 2, 175TH RR COY – NUI DAT From the earliest days of its deployment the Troop had been experimenting with an aerial radio direction finding solution capable of providing on-call support to the Troop whenever and wherever it was needed. With increased interest in an organic ARDF capability to support Troop operations, the Australian Weapons Research Establishment (WRE) began development on equipment suitable for mounting in a Cessna 180 at the time employed in a reconnaissance and light transport role. Tests continued in Australia and Vietnam and by the end of 1967 sufficient confidence was held in the equipment to aim for its permanent installation. The prototype ARDF installed into the Cessna produced excellent results. After the tests were completed it was intended that the equipment be taken back to WRE in Australia but when the Task Force commander (Brigadier Ron Hughes) heard of this he quickly claimed ownership and demanded it be kept in service. By early 1968 it was being used every day with great effect. In the meantime US air assets continued to provide an alternative (but less accurate) source of DF on enemy targets in the Australian area of operations. To augment the US ARDF operations, 303rd RR Bn decided that a ground based medium range DF capability should be deployed to Nui Dat. A request had been made in early January that an area suitable to the MRDF team’s needs be allocated within the Task Force base, but neither the commander nor deputy commander were available to give final approval. In the meantime, a team from 175th RR Coy was attached to 547 Sig Tp in order to test the AN/PRD-1 DF equipment, and in particular see how clear the VC communications were at this site. There is no record where in the Task Force area the ‘hearability team’ was located, but the results were evidently satisfactory because, after the team’s departure on 9 March, US authorities continued with their plans for a more permanent presence at Nui Dat.
Det 2 joins the Australians At the height of the Tet Offensive Detachment 2 (Det 2) of 175th RR Coy was sited on the outermost portion of the Bien Hoa base camp in an area known as ‘the Berm’. This was directly across the ring road from the perimeter wire and bunkers. At 0100 on 31 January 1968, the VC launched a sustained assault against the base. The wire opposite the detachment came in for particular attention and the troops were only saved by the timely arrival of Cobra gunships. The fighting lasted until dawn when the enemy withdrew, leaving behind over 200 dead and widespread damage to fuel and ammunition dumps, aircraft and buildings. Two days’ later Det 2 received direct hits from VC mortars, losing a “deuce and a half” (2 ½ ton) truck and transmitter hut. It was quickly decided that this was not
31 During the war the Task Force conducted many operations against D455. Ironically, The former VC battalion has a basic training camp at Nui Dat, the site of the Task Force.
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547 Signal Troop and the American Security Agency an ideal site for the detachment so it was planned that they should be located somewhere less prone to enemy interference. The Australian base at Nui Dat was reconsidered as sufficiently protected to enable the DF teams to continue their work unhindered. A request came into the Troop seeking assistance to find a suitable location for the detachment. An area was identified under the rubber trees less than a kilometre from 547 Sig Tp and adjacent to the Eagle Farm helicopter pad south of the 2nd Battalion, the Royal Australian Regiment (2 RAR replaced in June by 4 RAR). A working party from the Troop cleaned up the area recently vacated by the New Zealand company and prepared the ground for the incoming Americans. The detachment, under command of a US Staff Sergeant by the name of Seiber with additional personnel from Detachment 1 at Tay Ninh, duly arrived by truck, jeep and C130 Hercules aircraft. The US detachment of about 6 to 10 men traveled by road from Bien Hoa in time to welcome their AN/TRD-23 DF equipment, delivered by a Sikorsky CH-54 SkyCrane heavy lift helicopter. With the assistance of men from 547 Sig Tp they soon had the area cleared enabling the newly arrived American DF operators and technicians to quickly set up the DF shelter and erect the antennae on the open area. Tents were put up under the rubber trees and within a short period the Americans had established a restricted zone and settled down to begin operations.
Figure 17. Hand drawn map of Nui Dat base showing location of US and Australian SIGINT detachments The detachment arrived at a time when there was a high tempo of operations within the Australian Task Force Area of Responsibility. The records are not clear but it appears that as well as supporting other operations Det 2 was tasked with conducting SRDF tasks on intercepts captured by the Troop. The Americans of Det 2 had no intercept capability and relied on information generated by 175th RR Coy for
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547 Signal Troop and the American Security Agency tasking. However, despite reporting through the same headquarters CMA 175th RR Coy), and often supporting the same intercept or DF tasks, Det 2 and 547 Sig Tp were kept separate and, except for their commanders, later arrivals were unaware of each other’s presence at the base. Except at the highest levels neither did they know of each others’ tasking or priorities, although it is likely that these were being coordinated through the CMA, 175th RR Coy. By 1968 the VC and NVA had become very wary of the Australians and their aggressive patrolling techniques, and as a result had moved many of their headquarters’ out of the Task Force area of responsibility. As a fixed station the Det provided vital MRDF support to II FFV in the south and eastern regions of III CTZ, which by definition included the Task Force. The AN/PRD-1 DF equipment previously used by the ‘fly away’ teams had limited capacity outside of the Task Force Area of Operations and would have therefore only been used in identifying and locating the same enemy units being tracked by the Troop. The TRD-23 equipment employed by Det 2, on the other hand, had greater range, and it too would have been employed on targets within Phuoc Tuy or nearby provinces, not only the same enemy units being targeted by 547 Sig Tp but also those of interest to other DSUs operating at the edge of the Task Force’s area of responsibility. The intelligence gathered by the Det was fed back through 175th RR Coy and 303rd RR Bn, and returned to the Task Force in regular briefings and SPARs.
Figure 18. Inside the AN/TRD-23. Source: From TM 11-5825-231-2OP-1 Technical Manual. Given the parallel missions of Det 2 and 547 Sig Tp it is odd that the two units were not more intimately involved in each other’s day-to-day operations. Odd but not unexpected given that orders to deny the Troop’s existence within the Australian Task Force (or for that matter in Vietnam) were strictly adhered to, even to the point where
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547 Signal Troop and the American Security Agency the intelligence gathered by the Troop was in most cases firstly filtered through 175th RR Coy and 303rd RR Bn before being conveyed via the SSD liaison officers to the Task Force headquarters. (In one case it was suggested that an American officer be flown to Nui Dat to brief an SAS patrol rather than risk the squadron learning that the signals unit on the other side of the Kanga helicopter pad was the group tasking them.) Nevertheless, separation of the two radio research unit had its advantages, and its disadvantages. For example, all messing and recreation undertaken by the US troops was with the Australian infantry battalion alongside which the detachment had been placed. According to one former member of Det 2 their main day-to-day interactions were with the men of Whiskey and Victory Companies of the New Zealand Army. So close was this relationship that members of Det 2 were invited to join with the New Zealanders during the Battle of Binh Ba in June 1969.
Figure19. Spec 4 Dave Breisch at Nui Dat. Note the Australian boots and Self-Loading Rifle. Photo courtesy Dave Breisch Although unable to share details of their work with the Australian or New Zealand infantrymen, the Americans enjoyed a very active social life with members of the battalion. The above photograph shows one member of Det 2 (Sergeant Dave Breisch) wearing Australian boots and carrying a 7.62mm Self Loading Rifle, both of which he obtained (either legally or through nefarious other means) while located alongside 6th Battalion, the Royal Australian Regiment. The downside to being separated from their SIGINT cousins was that there was little opportunity to share experiences and techniques, and more importantly share real-time intelligence. For example, the results of the DF tasks carried out by the detachment had to be transmitted to 175th RR Coy where they would be analysed and the information transmitted up to 509th RR Gp who, through the National Security Agency’s Special Support Group (SSG), would report the findings to higher commands – including the commander of the 1 ATF at Nu Dat – and, of course, 547 Sig Tp. The reality is that it would have been quicker to walk the short distance between the units with this information.
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A death in the family Separation from their fellow operators at 547 Sig Tp also meant that the death of one of the Det 2 members due to a landmine a few kilometres south of the main gate at Nui Dat was a burden the small team had to carry alone. At 1445 on 25 February 1969, Corporal (later Sergeant) Dave Breisch and Specialist 5th Class (Spec 5) Harold Biller, a DF operator and analyst (05D10), were en route to Baria in their ‘deuce-and- a-half’ truck when a landmine exploded beneath them. Taking the full force of the explosion, twenty one year old Harold Biller was killed instantly and Dave Breisch was catapulted out of the truck and onto the road.
Figure 20. Dave Breisch with destroyed truck. Photo courtesy Dave Breisch. The Task Force was immediately alerted and a mine sweeping team under command of (Temporary) Staff Sergeant John Stahtoures was sent out to clear the area for medical evacuation. One Platoon from Charlie Company, 9 RAR, was dispatched on APCs to close the road and secure the site, while two combat teams from 2 Troop, 1 Field Squadron, swept the road 800 metres north of the site and 400 metre to the south, finding another mine which was destroyed. The engineers later reported that the mine that killed Biller was a home-made device with a wooden pressure switch. They were unable to determine how long it had been in place, nor the makeup of the explosives, but judging by the damage to the truck the mine had packed a sizeable punch. Corporal Breisch spent a few days as guest of the Australian 8th Field Ambulance (situated next to 547 Sig Tp) and was discharged, with ears still ringing and with two black eyes. In honour of his lost friend the Det 2 site was named Camp Biller.32
32 Ironically, the patch of ground that once housed Det 2 175th RR Coy is now the recruit training area for the 445th Battalion of the People’s Army of Vietnam (PAVN), also known as D445 Battalion,
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Figure 21. Camp Biller. Det 2 175th Radio Research Company, Nui Dat. Photo courtesy Dave Breisch Det 2 moves again In early 1970 the detachment was briefed on the capability of the recently introduced PC-6 Pilatus Porter aircraft being used by 547 Sig Tp for its ARDF tasks. Porter aircraft and ARDF equipment had arrived in South Vietnam on 28 November 1969. The new aircraft contained the same configuration as the Cessna but with upgraded electronics and was far superior in terms of accuracy and reach than the previous ARDF capability. It was also more effective than the US ARDF. Trials using the Porter had been running for nearly a year and by now the Troop, and through them the Task Force commander and USASA, had greater confidence in the results being achieved. It was decided therefore that Det 2 could be of better service to the intelligence network if it was deployed elsewhere. Shortly after the Porter ARDF commenced operations the detachment packed their equipment and belongings and moved offshore to Con Son Island, 60 miles off the south coast of Vietnam. Although seeming far away from the main areas of conflict, Det 2 was to suffer one more casualty. On 9 March 1970, twenty eight year old Specialist 6thClass (Spec 6) Edward Robinson, a DF equipment technician from Kansas City, Missouri, was swimming off Con Son Island. He was last seen standing on a wooden raft, waving in apparent distress. When rescuers reached the area they found the raft upturned and no sight of Robinson. His body was never found and he remains listed as missing in action.
one of the Viet Cong formations against which the Australian and US forces conducted operations during the war.
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Con Son Island was notorious as a camp in which male and female prisoners of war were held. It was also the site of a British secret communications base whose ‘cover’ story was that they were there in order to assist shipping through the South China Sea. Being across a wide stretch of water it was also an ideal location from which to undertake DF tasks in southern Cambodia and the Mekong Delta. The detachment remained here until early 1971 when they were brought back to Bien Hoa and integrated back into 175th RR Coy.
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PART FIVE – POSTCRIPT
In 2017 US Congressmen Mike Thompson and the late Walter B Jones sponsored an application to the then Secretary for the Army, General Walter Matthis, seeking an amendment to the Department of Army General Orders (DAGO). The purpose in seeking this amendment was to show that, like 175th RR Coy, 547 Sig Tp was assigned and attached to 509th RR Gp and 303rd RR Bn and thereby eligible for belated award of the US Meritorious Unit Commendation.
This application was supported by two citations from former commanders for whom the Troop provided direct support during the war (see copies below), but it was refused. The reason given by the Department of the Army was that 547 Sig Tp was supporting the Australian Task Force. The following is an extract from the Secretary’s letter:
The evidence upon which this decision was made is not clear. The Troop’s deployment orders clearly show that 547 Sig Tp was deployed under operational control of the US Armed Forces, and history reveals their actions and intelligence gathering activities were solely directed by US commanders. The Troop was DSU to the Australian Task Force, but under directions of the ASA, and ultimately the NSA.
This was confirmed by a later decision by the Australian Department of Defence that the Troop was indeed under operational control of US forces (and thereby eligible for the same South Vietnamese unit citations gained by 509th RR Gp and 303rd RR Bn). It was also confirmed by former commanders and senior officers within the US signals intelligence chain of command, although during the war – and, clearly, today – this was not always acknowledged.
A former officer commanding the Troop, Major (later Lieutenant Colonel) Steve Hart, recalls that sometime late in his tour (early 1969) he accompanied the
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547 Signal Troop and the American Security Agency commander of the 1st Australian Task Force, Brigadier ‘Sandy’ Pearson33 on a tour of the ASA headquarters groups at Long Binh and Saigon. According to Steve:
In Saigon we were given an extensive briefing in a large and well-furnished briefing room at 509th Radio Research Group. After Nui Dat the setting was quite luxurious. I remember there were comfortable armchairs in which we all sat surrounded by US advisors. After the presentation Sandy was speaking with the commander of the 509th Group and pointed to a wall on which was listed all of the ASA units in Vietnam. He asked the commander why 547 Sig Tp was not listed, after all it was ‘one of theirs’! There was an awkward silence and shuffling of feet before the subject was quickly changed and we were invited to move along. This was not the only time that the senior commanders in Vietnam had been interrogated on the reason for 547 Sig Tp being left out of the US chain of command. So too was Major General Charles Joseph Denholm, the commanding general of the ASA at Arlington, Virginia. For his actions during the mine incident outside the Australian base at Nui Dat, Dave Breisch was awarded the Purple Heart and the Army Commendation Medal. Around two weeks after the incident Major General Denholm, along with a large entourage of senior officers from Saigon and Bien Hoa, arrived at Nui Dat to visit Det 2 and present these medals. Steve Hart recalls: About two weeks before (their arrival), I had a signal from 509th RR Gp requesting permission of Brig (Sandy) Pearson for the CGUSASA Pacific, Major General Denholm, to land by helicopter for a short presentation award but without stopping. When the initial sig(nal) came in from 509 requesting approval to land, I passed it on to Sandy who directed me to reply along the following lines: “Brigadier Pearson would be delighted to greet the CGUSASAPAC on his proposed visit to his task force and extends an invitation for the general to make a brief inspection of his SIGINT unit which contributes to the overall allied intelligence operations in country.” It was an invitation that was pretty hard to ignore. The Task Force Commander also requested an emissary to (the) visit (of General Denholm) to explain. A Bird Colonel Godling [sic Godding later Brigadier General USASAPAC] subsequently arrived and we had a meeting with Pearson. The Colonel desperately tried to get approval for the brief stopover, claiming that the General had a busy schedule with many other stops that day and too
33 Brigadier Pearson, as Colonel, was the Director of Military Intelligence who approved the deployment of 547 Sig Tp to Vietnam and signed the deployment orders. If anyone within the Australian chain of command knew of the Troop’s place within the US SIGINT network it was he.
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long a stop would throw his schedule awry. Sandy wasn’t having any of it. Timetables were insignificant in a war when the activity was only ceremonial and stressed that since 547 Sig Tp was part of his (General Denholm’s) empire, he should delay awhile for a brief from the troop. Sandy made it perfectly clear that the general was welcome and would be met by Sandy personally and escorted to the troop with a promise that the briefing would be short. The day came when the official party arrived at Nui Dat and were met by the Task Force commander. The group then proceeded to Det 2 where the presentations were made and the General paid his respects at a small monument erected in honour of Spec 5 Biller. Dave Breisch remembers the occasion. He also recalls that, while speaking with the General, he raised the question about 547 Sig Tp and why the two groups were not working more closely together. According to Dave: I had not cleared it with anybody (and) that pissed some people off....but I was the wounded guy who got blown up so all I got was frowns, except Denholm said: “Something is wrong here”. (He) said he was going back the 175th to clarify. And your major that was your site commander at the 547th [sic – 547] also backed me.34 That put some of the officers under stress because Denhold[sic – Denholm] ran the whole show out of Arlington...and all of them were shaking.....so yeah...lost to history but I always thought I helped...... Steve Hart recalls what happened next: Biller was awarded the Purple Heart and Silver Star, afterwards a moment of reflection was held in his memory. I attended the ceremony, and shortly afterwards led the entourage to the (547 Sig Tp) compound where the General was given a quick tour through the set room followed by a briefing by the Troop’s XO, Captain Steve Zagon. The General, evidently impressed by what he saw, asked a lot of questions. I recall that the General asked: “How many guys have you got in this set-up?” I told him 35, at which the General then turned to his offsider and remarked: “These guys can achieve what they do with 35 men and you’re asking for a further 1,000 in country!” I do hate to see grown men squirm but I quickly realised why the subordinates didn’t want the general to visit! General Denholm’s reaction to being put on the spot twice concerning the operational arrangements between 547 Sig Tp and other ASA elements is not known. Around this time there was a high level of operational intensity requiring all signals intelligence assets to be functioning at their best, and it is likely that by the time he had returned to Saigon such links were the last thing on his mind.
34 It is possible that he is referring to Brigadier Pearson rather than Major Hart.
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With the passage of so many years it is impossible to speculate why the Troop’s name was never added to the list of ASA units under 303rd RR Bn, even after the intervention of the commander of the ASA, Major General Denholm. Some believe it was an oversight. Others are convinced that it was simply because the Australian government, through DSD, did not want it known that the Australians had a unit in Vietnam conducting spying missions. But the records are beginning to open, the first by the ASD who presented the Troop’s deployment orders during its response to the hearing held by the Tribunal into 547 Sig Tp’s eligibility for the Australian MUC. The NSA has also begun to declassify information, in particular a page from the detailed, but unofficial, history of the ASA in Vietnam – Spartans in Darkness: American SIGINT and the Indochina War, 1945-1975.
In a section entitled The Australian SIGINT Contribution35 the NSA conceded that the Troop worked closely with 175th RR Coy. Given that the only work which could have been undertaken between these units was in the form of a CMA and DSU, it is clear that even by implication 547 Sig Tp was a subordinate unit within the SIGINT command chain.
Being under operational control of the ASA, and not the Australian Task Force explains why the Troop did not appear on maps showing the layout of the Australian base at Nui Dat, nor has it appeared on the Vietnam Australian Order of Battle (ORBAT) or the AWM Vietnam display. Despite the lack of recognition then, and now, it is widely accepted throughout both the Australian and American signals intelligence community that 547 Sig Tp, despite the small number of operators and analysts, punched well above its weight. Australian ARDF results were often accepted in preference to those gained by US airborne DF teams, and on more than one occasion the timely intercept and analysis of enemy communications helped US and other allied forces either avoid combat for which they were not prepared, or aggressively turn an enemy action into a defeat. The soldiers themselves often went far beyond what their training and their deployment orders expected of them. The secrecy surrounding the Troop meant that on many occasions they had to enact the maxim that it is better to apologise than ask permission. One such occasion occurred on 11 August 1970 when the Troop identified an opportunity to take the fight up to the enemy, but in order to do so they had to become much more involved than anyone ever anticipated. Chasing the Chau Duc In early August 1970, the Troop were informed that they had to return one of their Land Rovers as the number they had was in excess of what was normally allocated to a sub-unit of that size. On 11 August the Troop OC, Captain Jack Fenton, visited the
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Task Force headquarters to argue the case for retaining this vehicle. While there he received an urgent message from the Troop that a transmission had been intercepted and decrypted from a local guerrilla force known as C41, also referred to as the Chau Duc District Company. The message from C41 Company was to their higher headquarters, D445, informing them that they were short of food and intended entering the village of Hoa Long that evening to replenish their supplies. Captain Fenton quickly relayed this information to the Task Force SO2 Intelligence who informed him that all available combat forces were tied up on operations. Together with the officer commanding the 1st Division Intelligence Unit (1 Div Int), they decided that if this intelligence was to be acted on the men would have to take the initiative and gather more information themselves in order to convince the Task Force commander to take further action. As he had no vehicle available to him (the point Captain Fenton was at the headquarters to argue), they borrowed one belonging to the officer commanding 2 RAR who at the time was talking with the Deputy Commander of the Task Force. The excuse was that they needed to get an operator to the airstrip urgently in order to conduct a priority ARDF mission. This was almost true, but that didn’t matter as Captain Fenton, along with the 1 Div Int OC and a hastily formed security team of intelligence and SIGINT operators sped out the gates of Nui Dat. They were headed for the rice fields between the Chau Duc base in the Nui Dinh hills and the village of Hoa Long. For close to two hours this little group wandered around the rice paddies searching for the faint pathways used by the VC on their trips into the village. Finding the most likely tracks they developed a plan for an ambush on the unsuspecting C41 guerrillas. Back at Nui Dat this plan was put to the Task Force commander who authorized the ambush and directed 8 RAR to deploy its forces that night. At 0315 the following morning, an estimated 50-60 VC wearing black pyjamas and carrying an assortment of weapons walked into the killing ground of an ambush laid by 8 Platoon of Charlie Company, supported by 1 Troop from Bravo Squadron, 3rd Cavalry Regiment. The VC had approached in two groups of approximately 25-30 men, moving about 50 metres apart. The contact was initiated with Claymore mines, grenades and automatic small arms fire. As flares illuminated the area it was clear that both groups had been caught in the open and suffered heavy casualties. The VC lost 19 killed (by body count), and 6 captured. Another later surrendered to the local forces. There were numerous blood trails and a significant amount of food, weapons, and other supplies were captured, including food and clothing for small children. On 21 August the Commanding Officer of 8 RAR had the following published in the battalion’s Routine Orders:
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For this, and other actions during its one year tour of duty, the battalion was awarded the RVN Gallantry Cross with Palm Unit Citation, one of only two Australian units to be so honoured by the Government of South Vietnam during the war. As for 547 Sig Tp, the only recognition sought – and received – was the return of the third Land Rover to its fleet of vehicles. Speaking of recognition Official recognition has never been forthcoming for the unit or the men who were deployed to 547 Sig Tp between 1966 and 1971 (or to those who remained in Vietnam until 1972). But neither did they seek it. Four members of the Troop were recommended for recognition through the award of the Mentioned in Dispatches, three of which were approved. But only one of these recommendations was for achievements made in the field of signals intelligence, and it was the only one to not be approved. When this information was put for former members of the ASA and surviving commanders of the units supported by 547 Sig Tp, many expressed surprise and disappointment. They were aware of the contribution the Troop made in the tactical and strategic successes achieved by II FFV, and the critical part it played in ensuring that the VC and NVA never gained any major successes within the Task Force’s area of responsibility. In the years following the 2015 report by the Tribunal in which it was made very clear that the Australian Army knew little about the Troop, there has been a combined effect to ensure that these achievements do not go unrecognized. This has been provided by former senior commanders within the US ASA and intelligence
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547 Signal Troop and the American Security Agency chain in the form of official citations for the Troop, recommending an award for the unit – although not specifying either an American or Australian citation. These recommendations are copied below, and illustrate not only how 547 Sig Tp fitted into the US ASA intelligence picture, but the respect and value placed on the work conducted by the Troop during its deployment to Vietnam. It is hoped that one day these recommendations can be revisited and the Troop receive the recognition that it deserves. Following are copies of citations (recommendations) submitted by former US commanders citing the Troop for its actions during the war.
Recommendation by Lieutenant Colonel (Retd) Richard W Catlett, supported by General (Retd) Joseph Freeze: LTCOL Richard W Catlett (Retd). CO SSG IIFFV GEN J Freeze (Commander 303d Radio Research Battalion)
NARRATIVE: I take great pleasure in recognizing the meritorious achievement of the officers and men of the 547 SIGNAL TROOP during the period July 1969 through July 1970. As the Commanding Officer, II Field Force, Special Security Detachment, United States Army Special Security Group (SSG), Assistant Chief of Staff for Intelligence Department of the Army, attached to the United States Military Assistance Command, Vietnam, I was in daily communications contact with the Troop via the special communications network. Due to the identical nature our sensitive and highly classified missions it was necessary to conduct numerous intelligence liaison and coordination meetings. During this period, Captain Brian Doyle and Captain Errol Poultney and their men demonstrated the highest degree of professional competence, initiative and devotion to duty in execution of all assigned II Field Forces tasks while achieving exceptional results in accomplishing greatly expanded operations missions during this period. The unit's collection and dissemination of critical intelligence was vital to information needed by ground commanders on a day to day basis for conducting operations. The outstanding performance of duty by the officers and men for extremely long periods each day under particularly trying condition significantly contributed to the curtailment of enemy aggression in the Nui Dat area and elsewhere in the Republic of Vietnam. The distinguished performance of duty by all members of the 547 SIGNAL TROOP represents great and outstanding achievement and selfless dedication which brings great credit upon all the officers and men of the unit, the Australian Armed Forces and the people of Australia. It was a distinct honor and pleasure to have worked with the 547 SIGNAL TROOP. I heartily recommend for the award of honors to the 547 SIGNAL TROOP. CITATION For exceptionally meritorious achievement in the performance of outstanding services: The 547 SIGNAL TROOP, while assigned to 509TH RADIO RESEARCH GROUP and attached to 303D RADIO RESEARCH BATTALION, distinguished themselves in support of military operations in the Republic of Vietnam during the period 1 June
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I966to 13 December 1971. The 547 SIGNAL TROOP demonstrated fortitude, uncommon skill, and unswerving dedication in providing timely and accurate intelligence to the II Field Force Vietnam. Displaying phenomenal versatility, the men expeditiously met each commitment and kept pace with the fluid combat situation. With professional skill and unrelenting effort, they labored far in excess of normal duty hours to ensure that all elements of the II Field Force received the best intelligence information. With superb foresight and rare adaptability, the members of the 547 SIGNAL TROOP overcame and minimized the problems inherent in providing intelligence support during a period of rapid increases in the intensity and scope of combat operations. They provided complete intelligence support to the combat soldier, which earned them the praise and admiration of combat commanders. Through their initiative, resourcefulness, flexibility and readiness to resort to the expedient, the Battalion and its assigned sub unit members have materially contributed to the counterinsurgency effort in the Republic of Vietnam. The remarkable proficiency and devotion to duty displayed by the members of the 547 SIGNAL TROOP are in keeping with the highest traditions of the military service and reflect distinct credit upon themselves and the Armed Forces of Australia.
Recommendation by Brigadier General (Retd) Joseph R Ulatoski BG (Ret.) Joseph R. Ulatoski (Comd 2nd Brigade 25th Infantry Division (Tropic Lightning))
NARRATIVE: During the period June 1970-April 1971, the undersigned was commander of the 2nd Brigade, 25th Infantry in South Vietnam, both as an internal 4000 man brigade and as a separate 6500 man brigade under II Field Forces after the 25th Division (-) redeployed to Hawaii. Throughout the time period mentioned, the 2nd Brigade's mission, whether under Division or II Field Forces, took it into an area removed from the division's formally designated area of operations. Initially the Brigade's new area of operations was east and south of Xuan Lac and was later expanded further in the Long Khanh and Long Binh areas. Because of its relative isolation, radio research support available from U.S. Army units was extremely limited. Since the Brigade's organic radio research capabilities were, for all practical purposes non-existent, assistance was sought from the Australian Army Unit operating in an area immediately south of the 2nd Brigade's area of operations. As a result of the request for assistance, direct contact was authorized with the 547 Signal Troop, an Australian Army unit deployed as part of the 509th Radio Research Group and assigned 303rd Radio Research Battalion of the United States Army. The requested help was immediately forthcoming and extremely effective. As the drawdown of U.S. forces in Vietnam continued and enemy activity expanded, the brigade's tempo of activity and area of operations expanded, as did the need for closer cooperation and coordination between the neighboring Australian, Thai and ARVN Army and local regional indigenous forces. Throughout the entire time period, the 547 Signal Troop provided the 2nd Brigade with valuable, timely and accurate intelligence, usually on short notice. As an example, in the area around the Nui Be Hills, 547 teams, regardless of the dangers involved in close combat, conducted independent surveillance and intelligence gathering activities which accurately identified enemy locations and routes of movement and resupply thus enabling increased interdiction and engagement. This pattern continued throughout the entire time period noted and the intelligence provided enabled the 2nd Brigade to maintain much more effective pressure on the VC within its area of operation, but perhaps even more importantly, to effectively coordinate and conduct joint operations with
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Australian, Thai, ARVN and local forces where enemy activities were taking place in areas that encompassed multiple allied force areas of operations. Without the outstanding intelligence support of the 547 Signal Troop, the 2nd Brigade and the other Allied forces operating in the area, would have been much less effective in accomplishing their assigned missions. I cannot recommend strongly enough that the support provided the 2nd Brigade, 25th Division by the dedicated troops of the 547 Signal Troop be recognized with the recommended award. They are among those troops who, in every army, provide the absolutely critical support necessary for mission accomplishment and whose activities, all too frequently, go unrecognized. Throughout my personal association with the officers and men of the 547 Signal Troop, I was not only impressed with the quality of their work, I was impressed by their overall professionalism, dedication, high morale, esprit de corps and their willingness to help the 2nd Brigade in any way possible.
CITATION For exceptionally meritorious achievement in the performance of outstanding services: The 547 Signal Troop, while assigned to 303D RADIO RESEARCH BATTALION, distinguished themselves in support of military operations conducted by the 2D BRIGADE, 25TH INFANTRY DIVISION in the Republic of Vietnam during the period 1 April 1970 to 30 March 1971. The 547 Signal Troop demonstrated exceptionally meritorious service in support of operations in the Long Binh, Xuan Loc and Long Khanh areas of South Vietnam. As the Brigade possessed only extremely limited organic radio research capability, 547 Signal Troop distinguished itself by providing at short notice intelligence support during a period of rapid increases in the intensity and scope of combat operations. During operations around the Nui Be Hills the Troop provided small teams of specialists who, with no fear of capture or injury, conducted independent surveillance and intelligence gathering which accurately identified enemy locations and suspected movements. Throughout the period the Troop demonstrated a high degree of initiative and flexibility and were a continuous source of timely ground and air intelligence on the enemy forces operating in the Brigade's area of operations. As a result continued pressure was maintained on the enemy which denied them access to safe havens and resupply. Throughout, the officers and men of 547 Signal Troop displayed outstanding professional skills, high morale, and exemplary esprit de corps in the execution of their missions. The remarkable devotion to duty demonstrated by the members of 547 Signal Troop are in keeping with the highest traditions of the military and reflect distinct credit upon themselves and the Armed Forces of Australia.
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GLOSSARY
ACI Airborne Communications Intelligence ACV Armoured Command Vehicle M577 AEF American Expeditionary Force World War I AFSA Armed Forces Security Agency AFV Australian Forces Vietnam AHQ army headquarters AMF Australian Military Forces APC Armoured Personnel Carrier M113 ARDF aerial/airborne radio direction finding/er ARDFCC Aerial Radio Direction Finding Control Centre ARVN Army of the Republic of Vietnam ASA Army Security Agency ASD Australian Signals Directorate ASMS Airborne Systems Management Section ATF Australian Task Force AWM Australian War Memorial
CCS Chairman of Chiefs of Staff Committee CINCPAC Commander in Chief Pacific CGS Chief of General Staff (Australian) CMA Collection Management Authority COMAFV Commander Australian Forces Vietnam Comd commander COMINT communications intelligence COMSEC communications security COSVN Central Office of South Vietnam (National Liberation Front) COMUSMACV Commander United States Military Assistance Command
DAGO Department of the Army General Orders Det 2 Detachment 2 DF direction finder/ing DIRNSA Director National Security Agency DMI Directorate of Military Intelligence DODSPECREP Department of Defence Special Representative DSD Defence Signals Directorate DSU direct support unit
G2 division level staff officer (Intelligence)
H&I harassment and interdiction HF high frequency
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INSCOM United States Army Intelligence and Security Command
J2 joint command staff officer (Intelligence)
LCU Landing Craft Utility
MI8 military branch number 8 MOS military occupational specialty MRDF medium range direction finder/ing
NLF National Liberation Front NSA National Security Agency NVA North Vietnamese army, Shortened form for People’s Army of Vietnam (PAVN)
OC officer commanding ORBAT order of battle
RAAF Royal Australian Air Force RAN Royal Australian Navy RDF radio direction finder/ing RIS Radio Intelligence Section RRCUV Radio Research Communications Unit—Vietnam RVN Republic of Vietnam RVNAF Republic of Vietnam Air Force
SAS Special Air Service SIGINT signals intelligence SIS Signals Intelligence Service SIT special identification techniques SPAR Special Agent Report SRDF short range direction finder/ing SSA Special Security Agency. (SIGINT Security Agency – USAFSS) SSD Special Security Detachment SSG Special Security Group
TAOR task force area of responsibility
US United States USA United States of America USAAF United States of America Air Force USAFSS United States Air Force Security Service USARV United States Army—Vietnam
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USASA United States Army Security Agency USASSG United States Special Security Group USMACV United States Military Assistance Command—Vietnam
VC Viet Cong. Alternative term for National Liberation Front (NLF) VHF very high frequency VNGB Vietnamese Guerrilla Morse code
WRE Weapons Research Establishment (Australia)
Military equipment
AN/ALR-34/35 Sanders-built Airborne Countermeasures Receivers Airborne Radio Direction Finding System (originally designated AN/ARD-18) used in EC-47N/P. AN/ARD-15 Airborne Radio Direction Finding and Surveillance HF Direction Finding System; used in RU-6A, RU-8D. AN/ARD-18 Airborne Radio Direction Finding (ARDF) System; manufactured by Sanders; became AN/ALR-34. AN/PRD-1 Army Navy/Portable Radio Direction Finder – 1. Direction Finder Set. AN/TRD-16 Army Navy/Transportable Radio Direction Finding Facility-16. AN/TRD-23 Army Navy/Transportable Radio Direction Finding Facility-23 and 23A. Deployable Medium Range Radio Direction Finding Shelter. AN/TRD-4 Army Navy/Transportable Radio Direction Finding Facility-4. AN/VRC-47 Army Navy/Vehicle Radio Communications System-47. EC-47 Douglas EC-47 Skytrain (also known as the Dakota in Commonwealth forces) military transport aircraft. Sometimes termed ‘electronic gooneys’. C-54 Douglas C-54 Skymaster. KY-8 NESTOR KY/8 stationary or vehicle mounted voice encryption system. TACAN Tactical Air Navigation System.
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Military Units 1 RAR 1st Battalion, The Royal Australian Regiment 2 RAR 2nd Battalion, The Royal Australian Regiment 5 RAR 5th Battalion, The Royal Australian Regiment 6 RAR 6th Battalion, The Royal Australian Regiment 1 ATF 1st Australian Task Force 1 ALSG 1st Australian Logistic Support Group 146thAvn Coy 146th Aviation Company (Radio Research) 173 Abn Bde 173rd Airborne Brigade (Separate) 175th RR Coy 175th Radio Research Company 199 LIB 199th Light Infantry Brigade 224th Avn Bn 224th Aviation Battalion (Radio Research) 274 Regt 274th Main Force Regiment (NLF) Also known as 4thĐồngNai Regiment 275 Regt 275th Main Force Regiment (NLF) 3rd RRU 3rd Radio Research Unit 303rd RR Bn 303rd Radio Research Battalion 313th RR Bn 313th Radio Research Battalion 372nd RR Coy 372nd Radio Research Company 403rd SOD 403rd Special Operations Detachment (DSU 5th SFG) 404th RRU 404th Radio Research Unit 5th SFG 5th Special Force Group 509th RR Gp 509th Radio Research Group 525th MI Gp 525th Military Intelligence Group 547 Sig Tp 547 Signal Troop 6994th SS 6994th Security Squadron USAFSS 7th RRU 7th Radio Research Unit 7th AF 7th Air Force USAFSS 8th RRFS 8th Radio Research Field Station 8th RRU 8th Radio Research Unit 860th LF Bn 860th Local Forces Battalion (NLF) AATTV Australian Army Training Team—Vietnam D445 445thProvincial Mobile Battalion (NLF) also known as the Ba Rai Battalion II FFV Second Field Force—Vietnam III CTZ 3rd Combat Tactical Zone VC 5th Div 5th Light Infantry Division (NLF)
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REFERENCES
Publications Bainbridge, N. (nd) 152 Signal Squadron. The History of the Corps of Signals in SAS 1957-1982. Success Print. Western Australia. Bergen, J. (1986) United States Army in Vietnam. Military Communications: A Test for Technology. Center of Military History. United States Army. Washington. Bonnot, D. (2010) The Sentinel and the Shooter. Wingspan Press. California. Boxal, R., O’Neill, R. (2020) Vietnam Vanguard: The 5th Battalion’s Approach to Counter-Insurgency, 1966. ANU Press. Canberra. Davis, Lieutenant M. (Ed) (1987) The Unclassified History of 547 Signal Troop in Vietnam. Published by author. Ekins, A with McNeill, I. (2012) Fighting to the Finish. The Australian Army and the Vietnam War, 1968-1975. Allen & Unwin. Sydney. Fairhead, F. (2014) A Duty Done (Second Edition). A summary of operations by the Royal Australian Regiment in the Vietnam War 1965-1972. On line http://rarasa.org.au/wp-content/uploads/2018/06/ADD-2-Ed-Combined-MkII- 32.pdf Finley, J. (Ed) (1995) U.S. Army Military Intelligence History: A Sourcebook. U.S. Army Intelligence Center and Fort Huachuca. Fort Huachuca. Arizona. Gilbert, J. (2003) The most secret war: Army signals intelligence in Vietnam. Military History Office. US Army Intelligence and Security Command. Fort Belvoir. Virginia Hanyok, R.J. (2002) Spartans in Darkness: American SIGINT and the Indochina War, 1945-1975. Center for Cryptologic History. National Security Agency. Hare, D (2001 r. 2008) Pronto in South Vietnam, 1962-1972. On-line http://pronto.au104.org/Pronto_Book/pronto_book.html?fbclid=IwAR1uW_c WNwcAuDDBvlYuMtcmDPpvhOWuehqeMDlOLI7VVvEqTFJQiJyfdw0 Hartley, R. & Hampstead, B. (2019) The Story of 547 Signals Troop in South Vietnam 1966 to 1972. Published by the authors. Hillier, J. (1993) No Medals in this Unit. Published by author. Horner, D. (1986) Australian Higher Command in the Vietnam War. Canberra Papers on Strategy and Defence No. 40. The Strategic and Defence Studies Centre. Australian National University. Canberra. Horner, D (1989) SAS: Phantoms of the Jungle. Allen & Unwin. Sydney. Luikart, K. (2018) The Uncomfortable Zone. Down from the Mountains. Xulon Press. Florida. McKay, G. (1999) Sleeping with your ears open. On patrol with the Australian SAS. Allen & Unwin. Sydney.
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McNeil, I. (1993) To Long Tan: The Australian army and the Vietnam war 1950-1966. Australian War Memorial. Canberra. Schlight, J. (1999) The United States Air Force in Southeast Asia. The War in South Vietnam. The Years of the Offensive 1967-1968. Air Force History and Museums Program. Tidey, B. (2007) Forewarned forearmed: Australian specialist intelligence support in South Vietnam, 1966-1971. Issue 160 of Canberra papers on strategy and defence. Strategic and Defence Studies Centre, ANU. Canberra. Stanton, S. (1981) Vietnam Order of Battle. Stackpole Military Classics. Stewart, R.W. (2012) Deepening Involvement 1945-1965. Center of Military History. United States Army. Washington DC. 2012
Australian Government publications Anon (2015) Inquiry into recognition for service with 547 Signal Troop in Vietnam from 1966 to 1971. Report. Defence Honours and Awards Appeals Tribunal. AHQ (DMI) Instruction No. 1/66 Comint Support for 1 ATF Vietnam. On-line Anon (nd.) Operation Drill Press. Part 1. Genesis and History. On-line. Accessed 27 March 2020 from http://ec47.com/storage/UserFileFolder/Drill_Press_1.pdf EC47 History Site http://ec47.com/phyllis-ann-makes-her-entrance Australian War Memorial AWM95 Subclass 1/3 – Headquarters, Australian Force Vietnam 1/3/9 - 1-31 May 1966, Narrative, Duty Officer's Log, Annexes 1/3/10 - 1-30 June 1966, Narrative, Duty Officer's Log, Annexes 1/3/11 - 1-30 June 1966, Annex A - Duty Officer's log 1/3/12 - 1-30 June 1966, Annex C 1/3/13 - 1-30 June 1966, Annex D and G 1/3/14 PART 1 - 1-30 June 1966, Annex H in 3 parts - part 1 1/3/14 PART 2 - 1-30 June 1966, Annex H in 3 parts - part 2 1/3/14 PART 3 - 1-30 June 1966, Annex H in 3 parts - part 3 1/3/15 - 1-30 June 1966, Annex L 1/3/16 PART 1 - 1-30 June 1966, Annex M in 5 parts - part 1 1/3/16 PART 2 - 1-30 June 1966, Annex M in 5 parts - part 2 1/3/16 PART 3 - 1-30 June 1966, Annex M in 5 parts - part 3 1/3/16 PART 4 - 1-30 June 1966, Annex M in 5 parts - part 4 1/3/16 PART 5 - 1-30 June 1966, Annex M in 5 parts - part 5 1/3/17 PART 1 - 1-30 June 1966, Annex J in 2 parts - part 1 1/3/17 PART 2 - 1-30 June 1966, Annex J in 2 parts - part 2 1/3/18 - 1-31 July 1966, Narratives, Duty Officer's log, Annexes 1/3/19 - 1-31 July 1966, Annex A
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1/3/20 - 1-31 July 1966, Annex C and D 1/3/21 - 1-31 July 1966, Annex E 1/3/22 - 1-31 July 1966, Messages part 1 1/3/23 - 1-31 July 1966, Messages part 2 1/3/24 - 1-31 July 1966, Messages part 3 1/3/25 - 1-31 July 1966, Annex H part 1 1/3/26 - 1-31 July 1966, Annex H part 2 1/3/27 - 1-31 July 1966, Messages from folder 3 1/3/28 - 1-31 July 1966, Messages from folder 3 continued 1/3/29 - 1-31 July 1966, Messages from folder 3 continued 1/3/30 - 1-31 August 1966, Narrative, Duty Officer's log, Annexes 1/3/31 - 1-31 August 1966, Annex A 1/3/32 - 1-31 August 1966, Annex C 1/3/33 - 1-31 August 1966, Annex I and L AWM98 R723/1/13/1/1 - June - December 1966, Monthly reports AWM98 R723/1/13/1/2 - January - June 1967, Monthly reports AWM98 R723/1/13/1/3 - July - October 1967, Monthly reports AWM98 R723/1/13/2 - October - November 1967, Monthly reports AWM95 Subclass 1/4 – Headquarters, 1 Australian Task Force 1/4/6 PART 1 - 1-31 August 1966, Narrative, Duty Officer's log - part 1 1/4/10 - 1-31 August 1966, Combat Operations - Operation Sydney II 1/4/11 - 1-31 August 1966, Combat Operations - Operation Hobart I and II 1/4/12 PART 1 - 1-30 September 1966, Narrative, Annexes part 1 1/4/12 PART 2 - 1-30 September 1966, Narrative, Annexes part 2 1/4/13 - 1-30 September 1966, Duty Officer's log | 1/4/14 PART 1 - 1-31 October 1966, Narrative, Annexes part 1 AWM95 Subclass 7/5 - 5 Battalion Royal Australian Regiment 7/5/2 - 20 April - 31 May 1966, Narrative, Operations log, Annexes 7/5/3 - 1-30 June 1966, Narrative, Operations log, Annexes 7/5/4 - 1-30 June 1966, Annexes 7/5/5 - 1-31 July 1966, Narrative, Operations log, Annexes 7/5/6 - 1-31 July 1966, Annexes 7/5/7 PART 1 - 1-31 August 1966, Narrative, Operations log, Annexes 7/5/7 PART 2 - 1-31 August 1966, Maps 7/5/8 - 1-30 September 1966, Narrative, Operations log, Annexes 7/5/9 - 1-31 October 1966, Narrative, Operations log, Annexes AWM95 Subclass 7/6 - 6 Battalion Royal Australian Regiment 7/6/1 - 9-31 March 1966, Narrative, Annexes 7/6/2 - 23 May - 30 June 1966, Narrative for May 1966 7/6/3 - 23 May - 30 June 1966, Annexes for May-June 7/6/4 - 1-31 July 1966, Narrative, Duty Officer's log, Maps, Annexes
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7/6/5 - 1-31 August 1966, Narrative, Duty Officer's log, Maps, Annexes 7/6/6 - 1-30 September 1966, Narrative, Duty Officer's log, Annexes 7/6/7 - 1-31 October 1966, Narrative, Duty Officer's log, Annexes AWM95 Subclass 7/12 - 3 Special Air Service Squadron 7/12/1 - 1-31 June 1966, Narrative, Duty Officer's log, Annexes 7/12/2 - 1-31 July 1966, Narrative, Duty Officer's log, Annexes 7/12/3 - 1-31 August 1966, Narrative, Duty Officer's log, Annexes 7/12/4 - 1-30 September 1966, Narrative, Duty Officer's log, Annexes 7/12/5 - 1-31 October 1966, Narrative, Duty Officer's log, Annexes US Sources 303D Radio Research Battalion Report. IAPV303TP. After Action Report (Support for REDACTED (1st Australian Task Force?)). Dated 30 September 1966. Anon. (1968) Supplement 1 to B62 COMINT Technical Report 33-67. VC-073. 26 July 1968. ‘SIGINT Indicators of Communist Tet Offensive, 1968’. National Security Agency. Fort George G. Meade. Maryland. Anon. (1970) Working Against the Tide (COMSEC Monitoring and Analysis). Part One. Cryptologic History Series: Southeast Asia. Anon. (1972) SIGINT Applications in U.S. Air Operations. Part One: Collecting the Enemy’s Signals. Cryptologic History Series: Southeast Asia. Anon. (1973) Evolution of American Military Intelligence. United States Army Intelligence Center and School. Fort Huachuca, Arizona. Department of the Army Pamphlet 672-3. Unit Citation and Campaign Participation Credit Register. Headquarters. Department of the Army. Department of the Army. Operational Report – Lessons Learned, Headquarters, II Field Force Vietnam, Period Ending 31 October 1970 Department of the Army. Operational Report – Lessons Learned, Combat After Action Report, Operation Toledo. Department of Army Technical Manual TM 11-5825-231-10-HR Direction Finder Set AN/TRD-15 and AN/TRD15A Department of Army Technical Manual TM 11-677 Direction Finder Set AN/PRD-1 Department of Army Technical Manual Tm 11-688 Direction Finder Set AN/TRD-4A Department of Defense Directive. Number 2 5100.20. The National Security Agency and the Central Security Service. History of the 6994th Security Squadron. 1 July-31 December 1966. 1 January-30 June 1966 1 July-31 December 1967 1 January-30 June 1967 1 July-31 December 1968
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