ORIGINS
OF
THB
ARMY
SECURITY
AGENCY
AND
INSCOM
The U.S.
Army
has supported
its fighting
forces
with
signals
intelligence
since
World
War
I. The
first
permanent organization
to
do this
was
established
in 1930 as
the Signal
Intelligence
Service.
During
World
War II, the SIS
(renamed
the
Signal
Security
Service
in
1943 and
later the Signal
Security
Agency
-
SSA)
exploited
the
communications
of both
Germany
and Japan,
shortening
the
war
and saving
many thousands
of
American
lives.
The SSA
was reorganized
as the
Army
Security
Agency
(ASA)
at
Arlington
Hall Station,
Virginia,
on
15 September
1945.
Operating
under
the
command
of
the
Director
of
Military
Intelligence,
the
new agency
had
a sweeping
charter.
It
exercised
control
functions
through
a
vertical
command
structure.
ASA
established
a worldwide
chain
of
fixed
sites
-
"fteld
stations"
-
while
maintaining
large theater
headquarters
in the
Far
East
and
in
Europe.
ln 1949,
all three
military
cryptologic
services
were centralized
under
the
new Armed
Forces
Security
Agency
(AFSA)'
the
precursor of
today's
National
Security
Agency.
ASA transferred
most
members
of
its large
civilian
headquarters
staff
to
AFSA
in
this
process. However,
because
of
the
need
once
again
to
support
troops
in actual
combat
in the
Korean
War,
ASA again
expanded,
deploying
tactical
units
on a
large
scale
to support
the
Army
in
combat.
For
the
first
time,
ASA
grew
to
include
groups and
battalions
in its
force structure.
In 1955,
ASA took
over
electronic
intelligence
(ELINT)
and
electronic
warfare
functions
previously carried
out
by
the Signal
Corps.
Since
its mission
was
no longer
exclusively
identified
with
intelligence
and
security,
ASA
was
withdrawn
from
G-2
control
and
resubordinated
to
the
Army
Chief
of Staff
as a
field
operatin!
agency.
In
the
1960s, ASA
was
again called upon to assist U.S. forces
in the field.
On
13 May 1961, the first contingent
of Army Security
Agency
personnel
arrived
in South Vietnam
(setting
up an
organization
at
Tan
Son Nhut
Air Base) to
provide
support to the
U.S. Military
Assistance Advisory Group
and
help
train
the
South
Vietnamese
Army.
During
the
early
years
of
conflict,
ASA
troops
in Vietnam
were
assigned
to
the 3rd Radio Research
Unit. Their
primary
mission was to locate Viet
Cong
transmitters
operating in
the
south.
This
mission
was
in
its early stages when one
of their
direction
flnding
(DF)
operators, SP4 James
T.
Davis,
was
killed in
a
Viet
Cong
ambush
on
a
road outside Saigon. The date
of the
ambush, 22December t961, made Davis the first
American soldier
to
lose
his life durins
the Vietnam War.
The
death of
Davis
brought home to ASA
the
dangers
of
proceeding
into the
jungle
with
short-range DF
equipment to locate
VC transmitters that might
be only a few
miles
away. Since radio
wave
propagation
in
Southeast Asia required that DF
equipment be
very close
to the
transmitteq
the obvious answer was to
go
airborne.
ASA engineers began
working,on the
problem,
and by March 1962
they had
their first airborne
DF
platform,
a single-engine atcraft
that
flew
low,
slow, and had room for only a
few
people.
In the
fall
of
1962,
one veteran arrived inVietnam
assigned
to the
3rd Radio Research Unit. He recalls that
after
Davis
was
killed
aperating a
jeep-based
PRC-10 directionfinding
unit,
someone
decided that this
function
could be better
handled
from
the
air
Within
days,
soldiers
in the
unit
were
calling it TWA
(Teeny
Weeny Airlines).
With
the introduction
of
large
U.S.
ground
combat elements
into South Vietnam in
1965,
the
ASA organization in-country
expanded. The
3rd
RRU
was
replaced
by
the
509th Radio Research
Group,
which
commanded three batfalions and company-size
direct
support
units
assigned to all
Army
divisions.
One of the 509th's
subordinate battalions
was the
224th
Aviation Battalion
(Radio
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