UNITED24 - Make a charitable donation in support of Ukraine!


CSC 1985
			Major G.E. Washburn
			Conference Group 12
			Individual Research
			Colonel Kline
                       Table of Contents
INTRODUCTION                                          1
CHAPTER 2:  THREAT                                   10
CHAPTER 4:  PROJECTED USAGE                          21
CHAPTER 5:  FREQUENCY MANAGEMENT                     27
CHAPTER 6:  CAPABILITIES                             35
CHAPTER 7:  LIMITATIONS                              39
CONCLUSION                                           52 
     In the mid 1970's, the United States Army began
development of a new generation of tactical radios entitled
Single-Channel Ground and Airborne Radio Subsystem - Very
High Frequency (SINCGARS-V).  SINCGARS-V was to provide a
replacement for the present AN/PRC-77 and AN/VRC-12 series
equipment.  Procurement or SINCGARS-V was to include approx-
imately 160,000 radios for the Army and 20,000 radios for
the Marine Corps.
     The planned introduction of SINCGARS-V into the Marine
Corps inventory brings about two significant developments.
First, the radio will provide digital communications down
to the platoon level.  Second, SINCGARS-V introduces
frequency hopping, a technology designed to provide protec-
tion from enemy Electronic Counter Measures.
     The new capabilities of SINCGARS-V have necessitated
a review or present employment doctrine for radios in the
VHF-FM band both for amphibious operations and land opera-
tions.  The need to review present doctrine and also the
impact or SINCGARS-V on freguency management procedures
resulted in the submission of a research topic to the
Command and Staff College by the Telecommunications Branch,
C4 Division, Headquarters Marine Corps.
     The scope of this study was originally aimed at the
freguency management issue.  The scope was expanded to
include emploment doctrine after a face-to-face meeting
with the Headquarters Marine Corps Project Officer.  Using
these two issues as a basis, the scope was again expanded
to provide an overview of the significant issues pertaining
     Objective research regarding SINCGARS-V has proven to
be very difficult.  The proponents and critics of the system
are equally intense and convincing.  The discussions which
follow are offered as objective analysis.  This study is by
no means inclusive.  A great deal of the significant infor-
mation regarding SINCGARS-V is either classified or closely
guarded by those associated with the project.
     The material presented is unclassified and has been
developed from technical journals, official government
reports and numerous conversations with both military and
civilian personnel associated with the development and
operational testing of SINCGARS-V.  It is also necessary
to note that information was not requested directly from
the program manager.  Official reports were provided by the
Electromagnetic Compatability Analysis Center with the
concurrence or the Army Project Office.
     This study is directed toward individuals who are
familiar with tactical communications.  Exhaustive explana-
tions of basic communications terms and concepts have not
been included.
     It is generally acknowledged that United States Armed
Forces rely greatly upon command and control as force
multipliers.  Advance technology greatly enhances a comman-
der's ability to remain abreast of a battlefield situation,
affording him a brief opportunity to act or react in the 
most effective manner.  To be successful, a commander must
retain the capability to integrate the actions of his forces
and their weapons systems.  This coordinated effort pro-
duces an economy of force.  While units in the field can 
physically protect their systems and installations, there
is little protection for the vital communications links
which provide both command and control.
     Since the beginning of the conflict in South Vietnam,
a great deal of attention has been focused on the develop-
ment of a means to protect both tactical and strategic
communications links.  The extraordinary growth of the
international communications industry has had a dramatic
effect on the military race to gain control of the unre-
stricted use of the electromagnetic spectrum.  Technological
breakthroughs have produced more secure, reliable and flex-
ible communications systems.  These developments have also
spawned a counter-technology oriented toward selectively
degrading or destroying these improved systems. The conflict
between these two disparate technologies is far from its 
     Electronic Warfare (EW) has been legitimized as a very
crucial facet of the modern battlefield.  The Soviet Union,
as well as a multitude of other nations have recognized the
importance of denying an adversary's use of the spectrum.
The loss of the ability to command and control would
devastate the operations of an American force.  Economy of
force cannot be achieved and thus, the probability of parity
with a numerically superior force is greatly diminished.
United States doctrine breaks the general idea of Electronic
Warfare into several major subdivisions.  These include
Electronic Warfare Support Measures(ESM), Electronic
Countermeasures (ECM), and Electronic Counter-Countermeasures
     ESM includes actions taken to search for, intercept,
locate and rapidly identify radiated electromagnetic
energy for the purpose of immediately exploiting it for
military advantages.  ESM provides the information base
required for the employment of Electronic Countermeasures
and Electronic Counter-Countermeasures.  ECM is comprised
of two elements.  A hostile station can either attempt to
prevent the passage of information by jamming or to provide
false information through electronic deception.  ECCM are
those measures taken to prevent an adversary from employing
ECM against friendly communication links.  ECCM is provided
both by operator training and through the use of electronic
     ECCM has evolved over the past two decades.  Initial
emphasis was on protecting the information transmitted from
one station to another.  As the Soviets invested heavily
in Radio-Electronic Combat (REC), this technique lost a
portion of its utility.  A renewed interest by Soviets in
locating and successfully jamming threat stations introduced
a form of electronic hide and seek.  As the Soviet Union
expanded its technology base, and coincidentally, reliance
on electronic means for effecting command and control, it
became apparent that jamming on the battlefield would have
to be employed in a fairly sophisticated and discriminating
manner to avoid the total elimination of all electronic
     The massive Soviet Radio-Electronic Combat threat
promoted intense research efforts in the West.  Although
much of this research was conducted independently over national
and corporate lines, a consensus was recognized regarding
the general requirements for a new generation of tactical
battlefield communications equipment.  Tactical communications
systems must provide message security and some form of ECCM.
The Western defense industry began analyzing the postulated
threat and plausible methods of combating it.  Several
private-venture programs emerged which were directed toward
producing the technology for an integral form of ECCM.  The
industry effort was concentrated on the Very High Frequency
(VHF) portion of the electromagnetic spectrum because it is
the most widely used frequency band on the battlefield.
VHF communications contain the preponderance of combat net
radios and tactical command and control links.
     Several techniques and areas of technology have been
investigated within the electronics industry.  This research
examined numerous options ranging from the improvement of
conventional single-channel radios which operate on a fixed
frequency or time agility.  Of the two high technology
solutions, frequency hopping has gained favor because of
relative simplicity and lower cost.
     Although the threat will be analyzed in detail in
another section of this paper, it is necessary here to
provide a short description to assist in explaining exactly
what a frequency hopping radio is.  At present, there are
two predominant Electronic Warfare techniques which may be
employed to disrupt radio traffic.  An adversary can  
attempt to jam a wide band of frequencies or direct jam a
relatively few high priority transmission paths.  The use
of wideband jammers has a distinct disadvantage.  The
efficiency of wideband jammers is dependent upon the degree
of saturation which can be achieved in the operational 
bandwidths.  An effective wideband jammer makes no distinc-
tion between friendly communications and those of the enemy.
The probability of encountering wideband jamming is a con-
tinuing source of speculation.  Assuming that an enemy
must employ some portion of the electromagnetic spectrum
to control his operations, it is very likely that jamming
may primarily be employed against only selected, high value
transmission links.
     In order to attack a specific link, it is necessary
to monitor a range of frequencies to determine whether or
not a transmission is being attempted.  The output signal
of a frequency hopping radio and the tuning of its cor-
responding receiver are synchronized and hop (or switch)
over a range of frequencies in a random manner.1  Theori-
tically, it is impossible to predict the changes in the
frequency hopset without a basic key.  The time spent on
any frequency is so short that is is virtually impossible
to detect the signal.
     Another form of protection stems from the short period
this type of  radio remains on a single frequency.  In the
event enemy equipment could be produced which would be
capable of intercepting a short burst of signal on a single
frequency before the radio link hops to the next, it would
not be able to associate the short transmission with a
particular net.2  If a large number of frequency hoppers
are employed in an area, the task of intercepting, follow-
ing and jamming becomes immensely complicated, if not
     Many of these statements must be qualified.  There have
been some new developments in the EW threat and also some
problems associated with the saturation of the battlefield
with frequency hopping radios.  These issues will be
discussed in depth later in this report.
     A great deal of interest has been demonstrated regard-
ing spread spectrum technology.  Extensive research by
private and national weapons manufacturers has produced an
array of equipment.  Generally speaking, these systems can
be categorized as either slow, medium or fast frequency
hopping radios.  Because such radios do not attempt to
overpower, but rather, to elude enemy jammers, an important
performance characteristic is the number of times the
radio hops from one frequency to another relative to time.
The slow hop is usually thought of as 100 to 200 hops per
second; fast hop as 1000 hops per second; and medium hop as
falling somewhere in between the other two.   Although hop
rate is always employed when categorizing different systems,
it is only off indirect significance.  The hope rate is
related to what some industry analysts consider the pre-
dominant factor - dwell time.3  To elaborate further,
dwell time is the period when the transmitter is on and its
target receiver is listening.  The enemy's ability to find
a transmission in a shorter period than the dwell time,
permits him to jam the transmission as well as follow it.
     Current development programs in this area of technology
are many.  At present, the only corporation pursuing the
production of a fast frequency hopping radio is Rockwell-
Collins.4   Slow and medium frequency hopping radios are
being developed by Australia,  Sweden, France, South Africa,
Israel, and the United States.  Among the competing manu-
facturers are International Telephone and Telegraph (ITT),
Plessey, Rural, Thompson-CSF, Marconi Space and Defense
Systems (MSDS), Harris and Tadiran.  The project logos
include:  SINCGARS-V, Project Raven, Scimitar, Jaguar and
     The United States Army has evaluated three frequency
hopping radio systems.  The contractors involved in the
competition were Rockwell-Collins, ITT, and Cincinnati
Electronics.  The expensive fast hopping radio produced
by Rockwell-Collins was the first to be removed from competi-
tion.  ITT was selected over Cincinnati Electronics in the
production of the slow/medium hopping SINCGARS-V.  Because
the Marine Corps will be relying on the Army for the pro-
curement of the new generation of tactical radios, there is
a great deal to be gained from analyzing the performance
     The SINCGARS-V System is being developed to reduce the
Soviet's ability to intercept, direction find, and jam
tactical radio nets.  Specific Soviet jammers include the
barrage jammer and the narrowband or spot noise jammer.  It
also appears that in the foreseeable future the Russians
will be able to produce a transponder, known as a follower
jammer.  This type of jammer is being developed specifically
to defeat the new generation of slow frequency hopping
tactical radios.  The narrowband jammer does not pose a
serious threat to any of the frequency hoppers.  Targeted
on an assigned frequency or range of frequencies, the
frequency hopper only occasionally arrives on the jammer
frequency.  When successful jamming occurs, it can only
affect the message bits being transmitted in the particular
hopping cycle (dwell).  To be successful in this limited
form of jamming, a jammer frequency must be on one of the
frequencies included in the hopset and the jammer must have
sufficient power to overcome the hopping signal.6  Attempts
to change the jammer frequency require a great deal of time
relative to the hopping of the target system.  Once again,
even a slow hopper will change frequencies between 100 and
200 times per second.
     Both the Army and the Marine Corps are moving toward
digital communications.  In fact, the Marine Corps Command
and Control Master Plan states the following:
          The basic objective of Marine Corps
          communications is the achievement of a
          fully digital communications environment,
          to exploit the inherent advantages of digital
          switching and transmission techniques.7
     SINCGARS-V will be employed for voice as well as data
communications.  The Corps' heavy reliance on tactical voice
communications nets will continue.  The success of a jammer
against digital voice signal is related to the bit error
rate (BER).  The intelligibility of digital voice degrades
as bit error rate increases and becomes successful when BER
exceeds 10%.8  In the 30 to 88 MHz operating band of
SINCGARS-V, a narrowband jammer would be able to produce an
approximately 0.1% BER in the frequency hopping radio.9
To be successful in achieving an effective level of jamming,
hundreds of spot jammers, operating as a system, would have
to be distributed throughout the battlefield.  Such a system
would be difficult to control and tactically unrealistic.
A variety of sources have concluded that the narrowband
jammer, while useful against present single-channel radios,
is not a credible threat against a frequency hopper.
     Barrage jammers still constitute a significant threat
to tactical communications.  By jamming across entire bands
of the electromagnetic spectrum, these jammers can effectively
block all the possible frequencies that could be employed
by a hopping radio.  Although extremely potent, there are
many significant limitations imposed by their usage.  When
in operation, the jammers radiate an easily detectable and
distinct electromagnetic signature.  Because of this sign-
ature and a lack of mobility, they become easily targetable,
high value installations.10  From a logistical standpoint,
broadband jammers consume large amount of power and are
expensive to procure, operate and maintain.11  The density
of barrage jammers also impacts upon their efficiency.
When deployed in small numbers against a frequency hopping
network, they can be defeated by deleting the jammed band
from the hopset.  This is easier said than done.  In large
numbers, these jammers can produce band saturation jamming.
And, if saturation is achieved, radio communications cease.
     There are two schools of thought concerning the pos-
sible employment of saturation jamming by the Russians.  One
point of view would highlight the fact that the Warsaw
Pact is deploying more and more sophisticated, electronically
controlled weapons systems.12  Their increased dependence
on command, control and especially communications, is
relative to their increased dependence on such sophisticated
systems. (C3).  Band saturation jamming denies the use of
the affected ban to both sides, thus it is doubtful that
the Soviets will sacrifice.
     Another point of view regarding the barrage jammer
suggests that it might be employed.  While it is true that
the Warsaw Pact is obtaining technology, this technology
only serves to complement vastly larger advantages in
numbers of soldiers and weapons systems.  Given their tact-
ical bent to mass huge armies and to utilize straight-
forward doctrine, it is conceivable that the soviets could
more easily do without communications.  Command and control
is more vital to the smaller force.
    The employment of jammers by the threat is indeed a
formidable obstacle to communications.  There are, however,
some performance loopholes associated with the narrowband
and wideband equipment.  It has been postulated that the
Warsaw Pact will develop technology to fill gaps present
in their other equipment and to counter frequency hopping
technology.  The transponder jammer provides such a
     There are widely varying opinions as to how rapidly
the threat can develop and field a functional transponder
jammer.  Regardless of the source, all seem to agree that
such a system will be fielded during the life cycle of
SINCGARS-V.  It can reasonably be assumed that since the
transponder jammer relies on speed, the sale of fast
frequency hopping equipment overseas might in the end,
only accelerate the Soviet Program.
    Industry sources have developed a hypothetical per-
formance profile of the follower jammer.  The transponder
operates by searching the spectrum for a target signal;
aligns the transmitter to the target signal frequency;
and begins jamming.13  When the frequency hopper changes
frequency, the jammer receiver stops and the spectrum is
scanned once again.  The race between the frequency hopping
radio and the transponder occurs in microseconds.  Time
required for the jammer to locate a signal, adjust and
begin jamming is referred to as "jammer response time".14
This response time must be short enough to allow the jammer
to jam the target receiver for a portion of the time it is
on an identified frequency before the receiver can hop to
a new frequency.  To be effective, the signal from the
jammer must overlap the dwell time of the target radio
by a minimum of 20%.15  There are other factors which
influence the success of either the transponder or the
frequency hopping radio.  These will be analyzed in the
succeeding section of this report.
     Comparisons of the performance of frequency hopping
technology against the transponder jammer can only be done
from a theoretical perspective.  Unclassified government
reports were not available on this subject, however,
technical journals have addressed predicted performance
comparisons.  As stated previously, much of this informa-
tion is prepared by industry sources and reflects the
competition between companies producing both fast and
slow/medium hopping radio systems.  Mr. P.E. Van, an
Advanced Programs Manager for Rockwell International,
provided an indepth analysis of performance against the
transponder jammer.16  It should be noted that Rockwell 
Collins is the sole U.S. producer of fast hopping equipment.
Nevertheless, his arguments appear theoretically sound and
worthy of analysis.
     It is necessary to predict the frequency response time
of a transponder jammer.  From what is known about Soviet
technology and U.S. technology, the jammer response time
is assumed to be less than 100 microseconds.17  The success
of such a jammer against a frequency hopping radio is
affected by the dwell time of the hopping radio, the
response time of the jammer, and the signal propagation
time.  The signal propagation time is governed by the
length of the transmission path and therefore is directly
affected by battlefield geometry.18
     The battlefield of the future will be extremely complex
from a communications standpoint.  Also, there are a great
many uncertainties pertaining to saturation and interference
produced by friendly as well as enemy equipment.  Acknowledg-
ing that electronic chaos may pervail, Mr. Van has limited
his comparisons to the level of one frequency hopping net
against a single transponder jammer.  Of the three para-
meters identified previously, only battlefield geometry
cannot be controlled by equipment designers.  The jammer
response time will be determined by threat engineers, while
the dwell time of the frequency hopping radio will be  
selected by the equipment buyer.  Of these factors, the
dwell time is the predominant issue because there are choices
available now, before frequency hopping equipment is
     To continue with Mr. Van's theoretical comparison, it
is first necessary to describe a basic tactical radio net
and make some assumptions regarding the transponder jammer.
Figure 2 is Mr. Van's idea of what a tactical net will
consist of.
      The hypothetical net approximates a net at the bat-
talion or company level.  The four radios on the net form
a total of six links as indicated on the figured.  The
initial jamming position has been placed approximately 3
kilometers from the Forward Edge of the Battle Area
(FEBA).  It is necessary at this point in the evaluation
that the jammer possess sufficient power to successfully
jam a frequency hopping radio provided that it is fast enough
to follow the hopset.  Given the predicted jammer response
time of 100 microseconds and assumed power output high
enough to actually jam, it is now possible to evaluate both
fast and slow/medium hopping radios against the transponder.19
As there is no published distinction between a slow and
medium hopping radio, the two are considered as slow in
this evaluation.  It is also necessary to reiterate that
the theoretical response time of the jammer is the dominant
factor in analyzing frequency hopset performance.
     As the Soviets do not now possess a transponder jammer,
there is no intelligence information regarding its response
time.  The point to remember in objectively reviewing the
Rockwell-Collins comparison is that any jammer which can
intercept and overlap the dwell time of a frequency hopper
will degrade its performance.  By choosing a relatively
slow follower jammer, it will naturally affect a slow
hopping radio to a far greater extent than a fast hopping
radio.  A fast follower jammer will severely degrade a
slow hopping radio and probably have a less severe effect
on a fast hopping radio.  Whatever the situation, the
slow hopping radio will be the most vulnerable.
     To review once again, for the purposes of comparison,
the jammer response time is 100 microseconds or less, the
fast hopping radio has a hoprate of 4,000 hops per second
with a dwell time of 125 microseconds, and the slow hopping
radio has a hoprate of 100 hops per second with a dwell time
of 4,500  microseconds.20  Although these hoprates do not
exactly represent production models, they approximate the
ITT SINCGARS-V (slow) and Rockwell-Collins (fast) prototype.
     Battlefield geometry has an impact on the propagation
time.  While the speed of a radio transmission is constant,
(the speed of light) the distance it must travel determines
the time required to make a transmission.  In practical
terms, it takes twice as long for a radio transmission to
travel two miies than it does to travel one.  Propagation
time becomes important because of its affect upon the
frequency response time of a jammer.  The performance of
the jammer in overlapping the target signal is reduced
because of the propagation time.  The further a jammer is
from its target, the longer the propagation time and, thus,
the overlap with the target signal will decrease.  This 
will decrease jammer effectiveness.
     In Mr. Van's analysis, he converted the propagation
time to an equivalent distance factor measured in meters.
Reducing this further, from seconds to microseconds, the
equivalent becomes 1m second - 300m.21  An electronic
signal travels 300 meters in one microsecond.  Mr. Van
employed this distance factor in constructing ellipses for
each link of the net with the receivers and transmitters
being the focus of the ellipses.  Each ellipse reflects
the time and distance factors which will permit jamming
dependent on the jammer response time and the speed of the
frequency hopping radio.  The jammer must be within the
ellipse to cause any jamming of the target signal.22  Once
again, for the purpose of digital voice communications, 20%
jamming will have a serious effect on the ability to com-
municate.  For instructional purposes, figures 1 through
9 have been extracted from Mr. Van's article and incorpor-
ated in this report.  His findings regarding fast hopping
performance are as follows:
     *  The jammer must move to a position very close
        to the net in order to cause any jamming on
        all links.
     *  The jammer could successfully jam three links
        if it were co-located with one of the trans-
        ceivers - a very unlikely condition.
     *  The jammer could successfully jam two links
        if located at the intersection of X1 - X3 and
        X2 - X4... also unlikely, but in this case,
        communications could be relayed around the
        jammer on the other links.
     *  There is no location where the jammer could
        successfully jam more than 50% of the links
        in this net.
     *  With the net and jammer locations shown in
        Figure 2, none of the links in this fast hop
        net are successfully jammed even though the
        jammer is very close (3km) to the net and
        the jammer response time (100 microseconds)
        is very short.23
     His findings regarding slow hopping performance are as
        * The transponder jammer jams all slow hop
          links in excess of 97%.
Click here to view image
        * The transponder jammer could move hundreds
          of kilometers behind the Forward Edge of
          the Battle Area and still cause 20% jamming
          of all slow hop links.
        * In order to make the slow hop performance
          equal to that of the fast hop in this net
          geometry, it is necessary to increase
          jammer response time from 100 microseconds
          to 3,600 microseconds.
        * An effective jammer against slow hop can
          be fielded in the next couple of years.
          Clearly, slow frequency hopping systems,
          cannot evade the kind of jammer projected
          for introduction during the life of the
          new combat net radio.24
     What conclusions can be drawn from this analysis?
First, there is a need to reevaluate the criteria which
prompted the U.S. Army to proceed with development of a
slow hopping system.  There are a number of factors which
could be included such as cost, flexibility, simplicity
and other operational requirement specifications.  However,
if the essential criterion for selection was ECCM perfor-
mance against the transponder jammer, then the decision
itself should be evaluated.
     There is a need to devote further study to the Warsaw
Pact's ability to produce a transponder jammer.  There is
a need to "what if" any possible development.
     The U.S. Army would very likely face the transponder
jammer in an area such as Central Europe.  The Marine Corps
is much less certain to meet such a threat.  Research
should be performed to determine if the SINCGARS-V is
suited to the diverse Marine Corps missions.  Low intensity
conflict may not require the transponder jammer.
     The Marine Corps is attempting to grapple with the
tremendous advances in electronics.  The management of
change brings new challenges which complicate the traditional
procurement cycle.  The Marine Corps Command and Control
Master Plan was published in 1983 as an attempt to con-
solidate all developments in the command and control area.25
The approach utilized in the Master Plan presented descip-
tions of equipment under development and diagramed snap-
shots of communications schemes using the new equipment in
a number of timeframes.  This approach to planning has
been criticized for reliance on equipment capabilities
rather than on present and future requirements that new
equipment must support.26   There are arguments to support
both viewpoints.  However, what must be remembered is  that
any snapshot of a future communications scenario can be
radically altered by technology at any time.  Despite this
criticism, the Master Plan is one of the few documents
which has considered procurement and employment information
regarding SINCGARS-V.
     Long before the publication of the Command and Control
Master Plan, the 1976 Joint Operational Requirement was
produced.27  Validated by the Joint Chiefs, it contained
a Required Operational Capability (ROC) that the Army had
forwarded.  The ROC outlined the need to develop specifi-
cations for a new family of VHF/FM single channel tactical
radios.  Some of the more significant statements extracted
from the ROC are as follows:
     *  The system must operate in a manner which does
        not discernibly degrade the communications
        capabilities of the radio set or its electro-
        magnetic environment.
     *  An ECCM capability will be available as a
        module for priority users as an application
        to the basic radio.
     *  The operational and organizationsl concept
        described for the Army is applicable for the
        Marine Corps.
     *  A retransmission/repeater capability for
        ground and airborne configurations must be
     *  An ECCM module attachable to the basic radio
        for selected/designated users and which can
        defeat the enemy's projected threat and
        continue to operate is an essential charac-
     *  Maximum advantage will be taken of previous
        developmental work to insure the acquisition
        of the latest state-of-the-art military
     Between the Publishing of the ROC in 1975 and the com-
pletion of the Marine Corps Command and Control Master Plan
in 1983, the Marine Corps had published a number of policy
statements which were subsequently included in the intro-
duction of the Master Plan.  There are several statements
which impact upon the SINCGARS-V program.  They are as
     *  System communications requirements will be
        met by the Landing Force Integrated Commun
        ications system (LFICS) which will provide
        the telecommunications required for the
        transfer of information in digital and in
        analog form.
     *  The effects of Electronic Warfare (EW) will
        be considered when acquiring tactical tele-
        communications equipment.  Systems will be
        capable of operating in a high ECM threat
     *  Requirements for operator and/or support
        personnel and requirements for personnel
        of higher mental groups must be identified
        and provided for as early as possible in
        the developmental process.
     *  Marine Corps requirements for new acquisi-
        tions will be satisfied, whenever suitable
        and acceptable, through the programs of
        other services and governments agencies,
        or through joint development efforts.
     *  C4 system specifications will require that
        the equipment be designated to operate in
        any area of the world to which Fleet Marine
        Forces may be deployed.29
     The stated objective of Marine Corps communication is
an achievement of a fully digital communications environment
to exploit inherent advantages of digital switching and
transmission techniques.30  The radio development concept
associated with this objective calls for VHF radios based
on 25 KHz channel spacing and 16 Kbps data rates.  Such
equipment must be capable of both voice and data inputs.
From a tatical perspective, the 25 KHz channelization
permits usage with present single channel VHF radios and
permits a phasing in of the digital equipment.  Single
channel radios will continue to carry a heavy communications
load despite the doctrinal shift to multichannel radio
systems.  The radios will remain the mainstays of communi-
cations at the squadron and battalion levels.34  Additionally,
the SINCGARS-V and other single channel sets will be relied
upon extensively during the initial stages of amphibious
operations as well as those situations where terrain,
mobility, and other circumstances preclude the use of
     SINCGARS-V first appears in the Master Plan in the
LFICS projection for the period of 1987-1990.  In the pro-
jection, SINCGARS-V is to replace the AN/PRC-77, the AN/VRC-12
series and the AN/GRC-160.32  Most of the equipment to be
replaced is approximately 20 years old and features dated
technology.  The basic SINCGARS-V radio provides a capable
and attractive alternative to this outdated equipment.
     In addition to the single channel and ECCM roles,
SINCGARS-V will also provide a capable backup for data
transmission should multichannel communications become a 
casualty from either battle damage or ECM.  SINCGARS-V also
has the capability to transmit facsimile and teletype
traffic.  Its purported 16Kbps data transmission rate would
make it useful at all levels for data traffic.
     In reviewing the Master Plan's 1991 summary of telecom-
munications to support major command, control and supporting
systems data transfer, it becomes apparent that SINCGARS-V
will not only provide a backup for multichannel but will
also provide key transmission links for Digital Communi-
cations Terminal (CT), the Marine Intergrated Fire and Air
Support System (MIFASS) and the Tactical Combat Operations
(TCO) system.33  Not all of these applications have proven
successful to date, however, these apparent deficiencies
will be discussed later in this report.
     SINCGARS-V will not only be the primary means of
tactical voice, it permeates both voice and data systems
throught the Marine Amphibious Force (MAF) level.  At the
infantry battalion, artillery battalion, artillery battery
and squadron levels, the only ECCM-protected data trans-
mission capability will be provided by SINCGARS-V.  The
Master Plan reiterates that the employment of VHF multi-
channel or single channel radios for this purpose proves
unsatisfactory in terms of surviviability.
     The need to be constantly on the move makes time
consuming antenna remoting more difficult and increases the
probability of enemy intercept, jamming, and artillery
attack.  This concept is suspect as operational tests of
the SINCGARS-V have demonstrated a need to remote antennas
to avoid friendly interference.
     Distribution of SINCGARS-V to the Fleet Marine Forces
is a key issue.  Operationally, the employment of SINCGARS-V
as a replacement for the PRC-77, VRC-12 and GRC-160 poses
no significant difficulties.  There are some range limita-
tions with SINCGARS-V because it is a digital radio.  However,
it does provide greater channel selection with its 25KHz
channel spacing; it is close to the state-of-the-art; and,
when operated as a single channel tactical radio, it is
relatively easy to operate with self-diagnostics to assist
in trouble-shooting.  Although SINCGARS-V is a suitable
replacement radio, it is an extremely expensive replacement.
Cost estimates vary widely.  However, the minimum estimated
costs for SINCGARS-V are eight times the cost of the present
equipment.  The maximum estimates are approximately double
the minimum.
     Distribution of SINCGARS-V as a frequency hopping radio
with its ECCM capability is a complex business.  Because of
friendly interference generated by frequency hoppers,
restrictions on mobility because of required antenna remoting,
and its employment for data transmission, there are only
certain nets SINCGARS-V can be used for and only at certain
levels of command.  There is also a need to vary any employ-
ment matrix which could be developed to prevent creating a
very distinguishable electromagnetic signature.
     The integration of SINCGARS-V into LFICS poses other
deficiencies which require further study.  Operational
testing has demonstrated that the Digital Communications
Terminal will not interface with SINCGARS-V for data traffic.
Difficulties in resolving this problem suggest the SINCGARS-V
may not be able to perform its prime function in the LFICS
     Management of the electromagnetic spectrum is a global
concern.  The phenomenal spread of communications technology
and the demand for this technology by all other nations has
greatly increased competition for the limited radio fre-
quencies available.  Unrestricted use of the spectrum by
any country, corporation, or organization can severely
impact upon the ordered use of the spectrum of others.
Spectrum management cuts across commercial, governmental,
and military lines.  Even within the United States, there
is intense competition between these sectors. The balance
now existing is indeed fragile.
    Military communications constitute only a portion of
a much broader international communications scheme.  Under
peacetime conditions, the use of the electromagnetic
spectrum is somewhat controlled.  The military employs only
a portion of the spectrum for operations and training.
There is a great deal of speculation regarding military use
of the spectrum during general or limited warfare.  When
comtemplating this issue, it is necessary to recognize
that, despite the intensity of military operations, there
is still a requirement for non-military communications.
     Another factor to consider is competition within
military forces for the portion of the spectrum allotted
to such.  This is particularly true within the United States
Armed Forces.  All branches of the military require radio
frequencies to exercise command and control.  There is  a
common technology producing service interference.  An
example of this would be the doctrinal use of VHF/FM radios
for tactical ground communications by both the Army and the
Marine Corps.  To take this a bit further, there is poten-
tial saturation of the spectrum by a given service on any
battlefield.  This potential exists because of the prolif-
eration of command, control and communications systems.
The intentional saturation of the spectrum or a portion of 
the spectrum by the use of Electonic Warfare greatly com-
plicates modern battlefield communications.
     To summarize, frequency management on the modern
battlefield cannot be done in a vacuum.  A frequency manager
must consider potential interference created by organic
equipment, interference from a commercial or governmental
use of the specturm, as well as the reverse; and the impact
that communications operation may have on host country or
international communications.
     SINCGARS-V and, in fact, all frequency hopping radios 
add a new dimension to frequency management.  Operations in
frequency hopping modes defies the relatively organized
idea of frequency management.  Because frequency hoppers
operate on a number of frequencies in a random pattern with
respect to time, it has become virtually impossible to
"neatly organize" the frequency scheme.  SINCGARS-V when
operating in the frequency hopping mode, can use up to 2,320
channels.34  The enormous number of variables introduced to
frequency management by the employment of such radios on
an already congested battlefield spectrum necessitated
further study.
     The U.S. Army, agent for the SINCGARS-V Program,
requested that the Electromagnetic Compatability Analysis
Center (ECAC) assist in the development of procedures to
reflect the frequency management requirements for the
SINCGARS-V radio.35  The results of the ECAC study were
published in a report entitled DRAFT SINCGARS FREQUENCY
MANAGEMENT PROCEDURES which was published in October of 1984.
The approach of the ECAC report was centered around the
unique requirements of SINCGARS-V and were summarized as
	  Significant changes will be the management
	  of multiple frequencies in one radio versus
	  the current management of only a single
	  frequency in a radio, as well as the auto-
	  matic loading of multiple frequencies and
  	  variables into the radio through the use
	  of computers...a method that cannot be
  	  accomplished by the operator manually.  The
	  total number of variables used for secure
	  operation of the radio nets across the
  	  entire battlefield poses unique distribution
	  problems for the battlefield spectrum
     The addition of the frequency hopping radio adds a
requirement for an automated or computerized system to sort
out communications variables; to ensure electromagnetic
compatability; and to reduce self-generated interference. 
The U.S. Army produced a Required Operational Capability for
what is now referred to as the Battlefield Electronics
Communications - Electronics Operating Instructions system
(BECS).  In addition to handling the SINCGARS-V unique
requirements, BECS was to be capable of generating, process-
ing, displaying, printing, and storing information for HF,
VHF/FM and UHF radio bands.
       The BECS functions regarding SINCGARS-V were directed
toward frequency resource files, Communications-Electronics
Operating Instructions (CEOI) information, frequency assign-
ments, transmission security (TRANSEC) keys, and hopset
data.  The BECS provided a means to electronically distribute
this information from the planners down to the SINCGARS-V
     To plan the frequency management procedures to
support SINCGARS-V, ECAC began by analyzing the number of
frequencies available for inclusion in the hopset of the
radio.  It is recognized that in the operating band of
SINCGARS-V (30-87.975 MHz), there is competition for the
spectrum from commercial radio sources.  In view of this, a
general assumption has been adopted to provide the commercial
operations protection.  The frequency resource within the
operating band  is decreased each time a protected frequency
is added.  The frequency resource then forms a pool from
which a hopset for SINCGARS-V can be extracted.  During the
development of SINCGARS-V, a decision was made to  employ
a universal hopset.  This means that under optimum conditions
all 2320 channels can be incorporated in the hopset.38  By
employing the universal hopset, it theoretically provides
the greatest ECM protection because the transmission can
vary over a wider range within the band.
     As stated earlier, there are some frequencies which
must be protected.  SINCGARS-V has the capability to delete
or lockout these frequencies from the universal hopset.
These lockouts are not necessarily limited to civilian
frequencies.  There are certain military frequencies which
require protection based on priority use, and possible
interference with adjacent or supporting units, or the type
of communications circuit involved.  The number of lockouts
has a direct effect on the ECCM effectiveness of SINCGARS-V.
Any reduction in the frequency resource produces a reduction
in the number of frequencies available for the hopset.  The
more limited the hopset, the greater the probability of
intercept and jamming.  Critics of SINCGARS-V cite this as
a significant deficiency.  The heavy world-wide use of the
electromagnetic spectrum in the VHF band produces many  
frequencies which fit the general criteria for a lockout.
The continued growth of national and international communi-
cations circuits as well as the military's increasing sat-
uration of the band will bring about even more restrictions
on the universal hopset.  Conceptually, this restriction
would also increase the probability of interference between
SINCGARS-V radios.
     Interference, whether generated by friendly equipment
or enemy ECM activity, has the same detrimental effect.
Critics of SINCGARS-V have concluded that realistic lock-
outs on the universal hopset could narrow the hopset to
such a degree that the radio would be very vulnerable to
a narrowband jammer.  Peacetime restrictions on the hopset
may also effectively preclude realistic operator training.
     Proponents of SINCGARS-V predict many of the restric-
tions on the universal hopset may be lifted when hostilities
commence.  Should this not occur, there are other alterna-
tives such as reducing transmitter power output, the use
of directional antennas, and the limiting of the use of the
universal hopset to a selected number of high priority
     The October 1984 ECAC report highlighted two other
areas of practical significance.  These areas are cosite
interference and retransmission.39  To begin, cosite
interference is electomagnetic interference produced by
radios operating in proximity to each other, as would be
the case in a command vehicle or command post.  Because of
the broad utilization of the VHF band by SINCGARS-V, there
is the possibility that potentially severe electromagnetic
interference may develop as the density of such radios at
a site increases.40  Cosite interference adds a new dimen-
sion to communications planning.  Under combat conditions
it may take considerably longer to determine if enemy
jamming is occurring.  In fact, jamming may be the least
difficult to solve when compared to having to analyze
which of several radios that are using hundreds of fre-
quencies may be producing the particular interference.
     To solve the cosite interference problem, ECAC recom-
mended use of minimum radio output power; physical separa-
tion of the antennas; and antenna remoting.41  Each of
these recommended courses has an impact on battlefield
tactics.  The use of reduced power output brings with it
a corresponding reduction in the range of the radio.
Decreases in range necessitate moving tactical headquarters
closer together or employing longer ranges, yielding less
ECM resistant forms of communications.
     Remoting is employed with present single channel
equipment to reduce interference and to change the electro-
magnetic signature of headquarters.  Remoting is a sound
communications practice.  However, it is not without draw-
backs.  Remoting takes time; decreases a unit's ability to
displace; and expands the security perimeter of a head-
quarters.  Central to this issue is how far the antennas
of frequency hoppers must be separated to reduce interference.
The potential exists that the use of SINCGARS-V may neces-
sitate the expansion of the headquarters area with the
resultant expansion of the security perimeter.  At the
same time, headquarters must be brought closer together
because of the range restrictions produced by low power
      Cositing interference also affects the use of SINCGARS-V
radios at a retransmission site.  The interference problems
are identical to those just discussed, however, they are
intensified because of the physical and technical confines
of a retransmission site.  As force mobility is enhanced
so is the probability that rapidly advancing forces may
out-distance their own communications.  The speed of
helicopters (JVX) coupled with unfavorable terrain, force
some communications trade-offs.  These trade-offs are also
affected by the reduced range of the SINCGARS-V.  To
sustain communications with a quickly advancing unit, it
is necessary to employ retransmission sites or to use high
frequency communications.  HF communications do not provide
the ECCM protection or the flexibility of SINCGARS-V.
Using the frequency hopper as a single-channel retrans-
mission site to avoid cosite interference and operator
problems, also significantly reduces ECCM protection. Un-
favorable terrain may also preclude HF communications.
Because of the potenetially severe interference problems at
a frequency hopping retransmission site, ECAC has strongly
recommended further testing.42
     The Required Operational Capability statement regarding
SINCGARS-V contained a number of broad statements directed
at what the radio should be capable of doing.  Prominent
among these required capabilities were a need for more
usable channels; a reduction in the operator burden caused
by weight, size and operational complexity; and the capabil-
ity for secure voice/data operation in a manner which did
not discernibly degrade the communications capabilities of
the radio set or its electromagnetic environment.43  Also
included were reductions in maintenance requirements and
life cycle costs, and improved equipment reliability and
     The threat statement contained in the ROC did not
specifically address potential development of the transponder
jammer.  The Defense Intelligence Agency publications which
provided the basis for the threat description jammer.  The
threat statement changed substantially after the development
process had begun.
     The essential characteristics portion of the ROC
included sixteen general concerns with the most noteworthy
being the requirement for a ground and air retransmission/
repeater capability; an ECCM module which could defeat the
enemy's projected threat; and the compatability with other
systems under development.44  The ROC also included a
proposed distribution scheme however, that was also overcome
by events.
     Between 1975, when the ROC was generated, and 1984,
when the ECAC testing was accomplished, the capabilities of
the radio were extensively refined.  The SINCGARS-V now
provides the following capabilities:
     1.   Voice
     2.   Data
     3.   Communications security (COMSEC) compatible
     4.   ECCM (frequency hopping) operation
     5.   Single channel operation
     6.   2320 channels (25KHz channelization)
     7.   Remotable
     8.   Interoperates with current series of VHF-FM
          radios on 50KHz channels
     9.   Six channel presets plus cueing frequency
    10.   Built in test (BIT) - self diagnostic
    11.   Channel scanning (single channel only)
    12.   Frequency offsetting (single channel only)45
     The original design concept for SINCGARS-V differed
from previous radio procurement programs.  SINCGARS-V
included the development of the basic radio, its communica-
tions security device, and its electronic counter-counter-
measures device.  This program attempted to integrate
development in all three areas from the inception.  Pre-
viously, such devices were developed separately, normally
by different contractors.
     Commercial literature prepared by the Aerospace/
Optical Division of ITT (SINCGARS-V contractor) highlights
a number of areas which the contractor endorses as user
benefits.46  Operational simplicity was a requirement stated
directly in the ROC.  ITT feels it has satisfied this
requirement in a number of ways.  To begin, SINCGARS-V is
a very flexible radio system.  It can be employed for voice
or data, unencrypted and encrypted text, and it can be
remoted.47  Further flexibility is added by its capability
to handle facsimile, teletype, and digital message devices.
There are also features designed to simplify the operator's
     Switching from the single channel mode to ECCM fre-
quency hopping mode is done with a single switch.  All of
the communications variables can be established in all
radios in a given net via a radio frequency link to all
stations on the net.  This eliminates the need to physically
transport and load these variables to establish reliable
communications.  The keyboard located on the transceiver
pemits the operator to check the status of the ECCM module,
the data module, the battery status, and other technical
performance factors.  The built in test (BIT) provides
fault isolation to subsystem component level.48
     The operation of frequency hopping radios requires
that they remain synchronized with other stations on the
net.  To ensure that all stations maintain the correct
Mission Day (MD) (calendar day) and Time of Day (TOD), the
Net Control station coordinates the first installation.
However, from then on this information is updated electron-
ically every time the Net Control Station communicates with
another net station.  In this manner, synchronized is
     As discussed previously, SINCGARS-V and its primary
ancillary devices were developed together.  Because of this
modular approach, it is much simpler to tailor the radio
set to best suit its mode of operation.  The compactness
of the radio set is also perserved.
     ITT's frequency hopping scheme in the SINCGARS-V
utilizes full band hopping.  In this matter, 2320 separate
channels are created using 25 KHz channels.  By employing
the full band, it becomes considerably more difficult for
an enemy to successfully defeat SINCGARS-V using a wide-
band or narrow-band jammer.  The contractor also contends
that full band hopping simplifies frequency management and
permits positive control over electromagnetic interference.
     It is necessary to analyze the capabilities and
performance of a new system of technology in an objective,
systematic manner.  The systems acquisition process of
the Department of Defense provides such a screening process.
Beginning with the submission of a Required Operational
Capability statement, a new requirement is scrutinized to
determine its validity.  The mechanism to accomplish
systems validation within the Department of Defense, is the
Defense systems Acquisition Review Council. The Marine Corps
has established an internal review process culminating in
a Required Operational Capability approved or disapproved
by the Marine Corps systems Acquisition Review Committee.
      The operational deficiency, operational concept,
essential characteristics, technical assessment and cost
assessment sections of the Required Operational Capability
provide the acquiring agent and the defense industry with
specific guidance.  Acquiring agent for SINCGARS-V is the
U.S. Army.  Marine Corps interest in the project is rep-
resented by project officers at Headquarters, United States
Marine Corps and at the Development Center, Marine Corps
Development and Education Center, Quantico, Virginia.
     During  the course of preparing research for this
report, a number of individuals now associated with, or
previously associated with SINCGARS-V were interviewed.
These interviews produced information favorable to SINCGARS-V,
as well as a great deal of criticism about the system and
its procurement history.  Having discussed capabilities
of SINCGARS-V is the previous chapter, it is appropriate
to take a critical look at the radio.
     The primary concern in evaluating any tactical system
is performance against threat.  An ancillary factor is what
the future threat will be.  The threat likely to exist
during the life cycle of a new system must be explored.
Comparison against the present threat is a finite matter.
However, the future threat is not easily determined.  In
evaluating SINCGARS-V, this issue becomes even more complex
because there are significant factors affecting performance
against both the present and future threats.
    There is a consensus among those interviewed and the 
technical journals that the future threat to frequency
hopping tactical radio nets is the transponder jammer.
There is disagreement regarding  just when the Soviet Union
will become capable of developing such equipment.  Beyond
this, there is considerable contractor squabbling regarding
just when the Soviets will perfect a transponder to effectively
target emerging radio systems.  Regardless, most sources are
highly confident that the transponder jammer will be
fielded during the operational life of SINCGARS-V.
     At issue is not only the performance of the slow-
hopping SINCGARS-V, but frequency hopping in general as an
effective Electronic Counter-Countermeasure.  Assuming that
the Soviets would target the SINCGARS-V initially, it is
also reasonable to assume that they could quickly expand
such technology to target fast hopping radio systems.  This
raises a broader question concerning whether the increased
costs and complexity associated with the frequency hopping
technology provide an acceptable trade-off for limited
protection against the threat.  Aside from the Rockwell-
Collins article discussed earlier in this report, almost
all of the limitations associated with SINCGARS-V apply to
frequency hopping radios in general, regardless of the
hoprate.  Because of the probable development of the trans-
ponder jammer, SINCGARS-V performance as an ECCM resistant
systemis questionable.  It is necessary to remember that
SINCGARS-V was developed to satisfy a number of needs
just one of which was the ability to withstand the degrada-
tion produced by enemy Electronic Warfare operations.
     A related problem is the performance of SINCGARS-V
against the current Soviet wide band and narrow band
jammers.  There is a basic issue invloved in this matter.
At present, there is no universally accepted plan for the
use of the electromagnetic spectrum under wartime conditions.
This situation exists because the electromagnetic spectrum
will become a part of the battlefield of the future.
Nonetheless, the most efficient way to begin examining such
a conflict is to start with the constraints imposed on the
battlefield by our own systems and doctrine.  As it is
unlikely that United States involvement in a conflict will
be unilateral, it is also necessary to consider the re-
quirements of allied military forces and government
     The VHF-FM band is heavily congested across the globe.
This situation is likely to become worse as command and
control systems proliferate in both military and civilian
sectors.  Other considerations are the intensity of the
conflict and the battle geography.  In a low intensity
conflict or insurgency, the United States, as well as our
allies may very much want to preserve and not interfere with
the existent national communications system.  In such a
conflict, the use of means of communications for other than
military purposes may, in fact, promote or expedite the
successful conclusion of hostilities.
     In high intensity conflict, particularly with the
Soviet Union, any attempt to control the electromagnetic.
spectrum may prove unsuccessful.  Reliance on very inflex-
bile doctrine and the very high probability means they will
seize the initiative and commence hostilities under condi-
tions which are favorable to them and provide them with
the opportunity to prepare detailed plans to defeat or
degrade any Western capability.  The Soviets can develop
tactical schemes which do not require the complex command
and control that is so vital to American and Western forces.
There is a very real possibility that barrage wide-band
jamming will be employed in any direct conflict with the
Soviet Union.  Under such conditions, the cost effective
Electronic Counter-Countermeasure  available may be an
aircraft with anti-radiation missiles or an artillery
barrage.  Frequency hopping is not a defense against barrage
    Despite claims to the contrary, SINCGARS-V is probably
the most complex tactical radio yet developed.  In all
fairness to the Army and the International Telephone and
Telegraph Company, who would both dispute this statement, 
the following justification is provided.
     There is some conditional validity to the contractor
claim that SINCGARS-V is a simple radio to operate.  The
conditions required to make this true are that all functions
on all SINCGARS-V net stations are fully operable, that Net
Control Station operators are thoroughly aware of radio
capabilities and that imaginative frequency management has
produced very little electromagnetic interference.
     The Net Control Station operator is the vital link in
the SINCGARS-V tactical radio plan.  His or her tasking
includes the responsibility for establishing, maintaining,
and controlling the radio net in a potentially hostile
Electronic Warfare environment.49  The Electromagnetic
Compatibility Center's study regarding draft SINCGARS-V
procedures included the following statement regarding the 
Net Control Station operator:
          Because of the inherent complexity of the
          frequency hopping radios, additional
          operational and management responsibilities
          have been delegated to the NCS operator.
          As a result of increased demands placed on
          the SINCGARS-V NCS operator, additional
          training and additional qualifications
          will be required.50
     The Net Control Station operator on a Marine tactical
radio net would typically be a Corporal or a Lance Corporal.
To better match the Marine and his responsibilities, it is
necessary to identify his functions on a SINCGARS-V net.
These responsibilities would include:
     *  insuring effective utilization of the
        frequency resource provided for net operation
        in accordance with the unit standing opera-
        ting procedure (SOP)
     *  net controlling   
     *  directing net start-up using Electronic Remote
        Fill procedures
     *  using only the minimum power required to
     *  answering cues
     *  maintaining communications discipline
     *  directing single-channel operations
     *  controlling late net entry requests
     *  insuring that net members have the correct
        CEOI/SINCGARS-V variables in their Electronic
     *  establishing and maintaining the net TOD51
     The management of Communications Electronic Operating
Instructions and SINCGARS-V variables includes the correct
usage of the net transmission security key, the hopset,
the net identification, the Electronic Remote Fill Frequency,
the cueing frequency and finally, the Mission Day/Time of
     The typical net station radio operator within a Marine
tactical radio net is a Private First Class.  Depending
upon the tactical situation and unit involved, the
radio operator may or may not be a communicator by occupa-
tional speciality.  The SINCGARS-V radio operator does not
have as many management responsibilities as the Net Control
Station operator, however, he is directly responsible for
properly using the SINCGARS-V variables, being aware of the
net identification assignments and following the instructions
of the Net Control Station.53
     From a practical standpoint, radio operators employing
SINCGARS-V will be responsible for many more functions than
with present equipment.  The brief descriptions just provided
do not encompass the operating responsibilities and trouble-
shooting procedures required in the event SINCGARS-V is
used as a transmission means with another C4 systems such as 
the Digital Communications Terminal.
     Testing operating procedures such as those described
above in a test bed or controlled environment may, in fact,
demonstrate that radio operators of average capabilities
are capable of operating a SINCGARS-V radio net.  However,
employing the radio under field or tactical circumstances
may prove the opposite.  The following questions are certain
to arise:
     *  Is it prudent to assume that the operator
        has the ability to perform frequency
        management and to recognize and control
        electromagnetic interference?
     *  Is it reasonable to assume that the average
        radio operator can manage six communications
        variables under field or combat conditions?
     *  Should communications be disrupted, how
        long will it take a radio operator to
        troubleshoot and reestablish communications
        under tactical conditions?
     *  If interference is being generated by enemy
        Electronic Countermeasures, another 
        SINCGARS-V station, or other colocated
        equipment, will the radio operator be able
        to isolate the source?
    From a higher level perspective, another SINCGARS-V
variable has been added to the previous list:  operator
     There has been a great deal of testing done with the
SINCGARS-V radio system.  Appendix A of the October 1984
Electromagnetic Compatability Analysis Center report pro-
vides summaries of twenty-four projects and reports.54
These reports vary in their security classifications, many
of which could not be incorporated into this paper for
security reasons.  Informal, unofficial information con-
cerning the testing process was furnished by individuals
who are directly involved with SINCGARS-V development.
Several of these individuals expressed a concern that
sufficient testing would not be completed prior to testing the
radio.  This suspicion followed relatively poor performance
of the radio during manufacturer's demonstrations.  In
addition, the unusually long testing cycle had been stretched
to coincide with the fielding date of the equipment.  A
great deal of testing has been done on a theoretical level
without the use of an actual SINCGARS-V radio.
     Aside from the Electronic Counter-Countermeasures
capability provided by frequency hopping, the single most
significant operating feature is that is provides digital
communications.  This development adds unprecedented flex-
ibility to Marine Corps communications.  The conversion
from analog to digital was the predominant communications
objective contained in the Marine Coprs Command and Control
Master Plan.55  Paralleling the development of SINCGARS-V
are several other systems band technologies which will
fully exploit the speed, security, and flexibility of data
     The design objective data capacity for SINCGARS-V is
16 kilobits per second (Kbps).56  This standard assures a
minimum data transmission rate to provide interoperability
with other equipment developed under the TRI-TAC program.
Information was obtained from sources who have stated that
the manufacturer is having difficulty operating SINCGARS-V
with a data transmission rate in excess of 12 Kbps.
    Further difficulties have appeared during testing of
SINCGARS-V with the Digital Communications Terminal.  One
problem appears to involve hardware matching between the
SINCGARS-V and the Digital Communications Terminal precluding
employment in concert.  This situation is analogous to
other SINCGARS-V difficulties where the complexity of the
system defies timely fault isolation. This leads to con-
jecture that if at such a late stage in development engi-
neers and project officers are encountering difficulties,
what will be impact when the system is introduced to the
     All digital radio systems have limited range relative
to the older analog systems that they replace.  This is
produced by the greater sensitivity of digital radios to
signal strength and single-to-noise ratio.  Once again,
this is true of all digital radios, not just SINCGARS-V.
One of the operational trade-offs associated with the
employment of SINCGARS-V will be decreased distance between
operating stations if a net or data link is to function
successfully.  This has an enormous tactical impact not
only on smaller units, but also the positioning of higher
headquarters which will require extensive data communications.
     It has been recognized for quite some time that the
range of communications systems has not expanded to ade-
quately support mobile, fast-moving operations that are
rapidly becoming the rule, rather than the exception.
To assist SINCGARS-V in meeting this challenge, a power
amplifier has been incorporated into a long range version
of the radio.  It has been reported that the amplifier
has been unsuccessful to date in producing any significant
gains in system range.  Remember also the previous discus-
sions of the difficulties in cosite operation of high
power SINCGARS-V radios.  Range limitations also favor
present threat jammers and the future transponder jammer.
     The evolution to "over-the-horizon" amphibious oper-
ations will occur during the life cycle of the SINCGARS-V
system.  Given the range limitiations just discussed, one
can conclude that unforseen hazards await such operations
if they are, in fact, dependent on frequency hopping or 
digital communications.  Present communications doctrine
places heavy reliance on VHF-FM secure circuits to support
amphibious operations.  The Marine Corps Command and
Control Master Plan suggests the employment of SINCGARS-V
in the data mode to sustain ship-to-shore communications
until multi-channel can be established ashore.  This fact
spawns a number of acute problems.
     Electromagnetic interference is an enormous problem
aboard ship.  In addition to the very large number of
electronic emitters in the radio suite, every piece of
machinery aboard produces some sort of interference.
These two conditions combined, have made frequency manage-
ment very difficult under the best conditions.  Aboard an
ambhibious ship, the situation is aggravated by the large
number of ship-to-shore circuits required by the Landing
Force for Command and Control purposes.
     Under current frequency management procedures, obtain-
ing reliable communications is difficult and, often times,
impossible. The massive colocation interference aboard ship
makes trouble shooting an endless process.  Given the simp-
licity of the present single-channel concept of communications
and the difficulties involved, what will occur if complex
frequency hopping and data communications are added?  A
frequency hopping radio will add enormous complexity to the
already difficult shipboard frequency management picture.
     If SINCGARS-V is to be part of the ship-to-shore com-
munications scheme for over-the-horizon amphibious operations,
there are two other significant limitations.  First, the
range required for such operations clearly exceeds the cap-
ability of SONCGARS-V.  A retransmission capability is a
necessity.  The potentially severe eletromagnetic interfer-
ence problems associated with SINCGARS-V retransmission sites
were discussed earlier.  Because antennas cannot be remoted
in the amphibious environment, both the receive and transmit
antennas of a retransmission station must be located on a 
single airborne or seaborne plateform.  It is probable that
frequency hopping retransmission may prove impossible from
an airborne platform.  Electromagnetic interference
produced by the SINCGARS-V radios, an aircraft's single-
channel radios, and the addition of the aircraft's own
Have-Quick frequency hopper may preclude any successful
communications.  Retransmission through a dedicated
vehicle such as a Remotely Piloted Vehicle may prove im-
possible because the vehicle's small size would preclude
even minimal separation required for antenna systems.
Additionally, the control link for the vehicle itself may
not be able to withstand the electromagnetic interference
that is produced.  Retransmission from a seaborne platform
is susceptible to the same kinds of interference problems
discussed above.
       In examining the balance between the capabilities and
limitations of SINCGARS-V, it is evident that limitations
now overshadow capabilities with the radio system.  The
existence of such crucial deficiencies so late in the
development and procurement cycle should prompt a reeval-
uation of the program.  The Marine Corps should  review the
requirement which spawned the system, and act to ward off
the disaster materializing.
       The original Required Operational Capability generated
in 1975, identified a need to develop some replacement for
the aging AN/PRC-77 and AN/VRC-12 series tactical communi-
cations equipment.  That system was to provide more usable
channels as well as the ability to communicate by secure
voice and data without creating excessive electromagnetic
interference.  Further criteria included: that the new
system provide for retransmission; that the new radio be
relatively simple to operate; and finally, that the system
provide protection in the Electronic Warfare environment.
From the beginning, SINCGARS-V has evolved into a very
complex radio system.  To objectively evaluate the system,
it is reasonable to compare what the acquisition of
SINCGARS-V provides, relative to what it was supposed to
provide at its inception.
     As a replacement for aging equipment, SINCGARS-V is
considered a success.  SINCGARS-V provides an expanded
number of channels, a self-diagnostic system, and boasts a
more modern radio technology.  It does not, however, replace
some key capabilities of the older equipment.  It is
deficient in both operating range and retransmission capa-
     SINCGARS-V can successfully provide  secure voice
communications and yields, at present, a slightly degraded
data transmission capability.  Its success  in performing
these functions without producing excessive electromagnetic
interference is largely dependent upon its operation in a
single-channel mode.
       There are several problems associated with the operation
of SINCGARS-V as a frequency hopping system.  The perform-
ance of SINCGARS-V in this ECM resistant mode is adversely
affected by the potential development of a near term
threat transponder jammer; the limited frequency spectrum
which may be utilized; and the serious electromagnetic
interference generated by architecture limitations.
     The operational simplicity of SINCGARS-V is a moot
point.  Proponents of the system argue that simplicity
has been built into the system and that, to some degree,
the radio is easier to operate because of its self-diagnostic
device and its ability to use Electronic Remote Fill to 
electronically update variables in net station radios.
    Critics of the system contend that, given the numerous
other deficiencies of SINCGARS-V and the greatly expanded
number of variables required for operation, the radio
exceeds the operational and troubleshooting skills of an
average radio operator.
     There is a great deal of pessimism afoot.  SINCGARS-V
is not so hot.  The expressed frustration and doubt about
the radio wears the frown of fatalism.  Is the system
going to be force-fed regardless of the hazards forseen?
     While it is easy to generalize and categorically
recommend that SINCGARS-V not be procured,  it is obvious
that the situation is not that simple.  Instead of writing
doctrine to support equipment, there is a need to identify
a communication doctrine requirement and then develop
equipment to support it.  SINCGARS-V may in fact satisfy
some doctrinal requirements and not others.  A complete
reevaluation of the program is in the best interests of the
United States Marine Corps.
1.  P.E. Van, "New Concepts in Battlefield Communications
    Part 1 - fast frequency hopping",  International
    Defense Review, March 1982, p. 327.
2.  Ibid., p. 329.
3.  Ibid., p. 327.
4.  G.S. Sundaran, "New Concepts in Battlefield Communi-
    cations Part 2 - slow/medium frequency hopping",
    International Defense Review, May 1982, p. 562.
5.  Ibid., pp. 562-563.
6.  Van, "New Concepts in Battlefield Communications Part
    1 - fast frequency hopping," p. 328.
7.  United States Marine Corps Command and Control Master
    Plan, Headquarters U.S. Marine Corps, March 1983, p.5-3.
8.  Van, "New Concpets," p. 328.
9.  Ibid., p. 328.
10. Ibid., p. 328.
11. Ibid., p. 328.
12. Ibid., p. 328.
13. Ibid., p. 328.
14. Ibid., p. 328.
15. Ibid., p. 328.
16. Ibid., pp. 327-330.
17. Ibid., p. 329.
18. Ibid., p. 329.
19. Ibid., p. 329.
20. Ibid., p. 329.
21. Ibid., p. 329.
22. Ibid., p. 329.
23. Ibid., p. 330.
24. Ibid., p. 330.
25. Command and Control Master Plan
26. S.L. Pipho, point paper prepared for the USMC Development
    Center, September, 1984, "A Development Strategy  for a
    LFICS/C4I Architecture".
27. Joint Chiefs of Staff, memorandum to the Secretary of
    Defense, 26 March 1976,  "Joint Operational Requirement
    for a Family of VHF/Frequency Modulated Single Channel
    Tactical Radios, "  JCSM - 110-76.
28. Ibid.
29. United States Marine Corps Command and Control Master
    Plan, Headquarters U.S. Marine Corps, March 1983,
30. Ibid., p. 5-3.
31. Ibid., p. 5-2.
32. Ibid., Appendix D.
33. Ibid., Appendix D.
34. Electromagnetic Compatability Analysis Center, Draft
    SINCGARS-V Frequency Management Procedures, study prepared
    for the U.S. Army Signal Center by Troy N. Allen and
    Lawrence L. O'Neill, October  1984, p. 2-1.
35. Ibid., p.  1-1.
36. Ibid., p.  1-2.
37. Ibid., p.  2-4.
38. Ibid., p.  3-1.
39. Ibid., p.  6-2.
40. Ibid., p.  6-2.
41. Ibid., p.  6-1.
42. Ibid., p.  6-2.
43. Joint Chiefs of Staff, memorandum to the Secretary of
    Defense, 26 March 1976, "Joint Operational Requirement
    for a Family of VHF/Frequency Modulated single Channel
    Tactical Radios",  JCSM-110-76.
44. Ibid.
45. ITT Aerospace/Optical Division, commercial circular,
    "SINCGARS-V, the Voice of C3I".
46. Ibid.
47. Ibid.
48. Ibid.
49. Electromagnetic Compatability Analysis Center, Draft
    SINCGARS-V Frequency Management Procedures, study
    prepared for the U.S. Army Signal Center by Troy N.
    Allen and Lawrence L. O'Neill, October 1984, p. 2-1.
50. Ibid., p. 5-9.
51. Ibid., p. 5-10.
52. Ibid., p. 5-11.
53. Ibid., p. 5-13.
54. Ibid., Appendix A.
55. United States Marine Corps Command and Control Master
    Plan, Headquarters U.S. Marine Corps, March 1983, p.5-2.
56. Joint Chiefs of Staff, memorandum to the Secretary of
    Defense, 26 March 1976, "Joint Operational Requirement
    for a family of VHF/Frequency Modulated Single Channel
    Tactical Radios",  JCSM-110-76.
Adrian, Serge, and Rabian, Jacques, "Frequency Hopping for
    Tactical Radios:  the Thomson CSF Philosophy , Special
    Electronics, January 1984.
Electromagnetic Compatability Analysis Center, Draft SINCGARS--V
    Frequency Management Procedures, study prepared for the
    U.S. Army signal Center by Troy N. Allen and Lawrence L.
    O'Neill, October 1984.
Electromagnetic Compatability Analysis Center, EMC support
    for U.S. Marine Corps Communications Planning Concept,
    study prepared for USMC Development and Education
    Command by E.R. Velie, September 1984.
ITT Aerospace/Optical Division, commercial circular,
    "SINCGARS-V, The Voice of C3I".
Joint Chiefs of Staff, memorandum to the Secretary of Defense,
    26 March 1976, "Joint Operational Requirement for a
    family of VRF/Frequency Modulated Single Channel Tactical
    Radios," JCSM-110-76.
Pipho, S.L., point paper prepared for the USMC Development
    Center, September 1984, "A Development Strategy for a
    LFICS/C4I Architecture".
Sundaram, G.S., "Anti-Jam Communications: The Spread
    Spectrum Solution", International Defense Review, March
Sundaram, G.S., "New Concepts in Battlefield Communications
    Part 2 - slow/medium frequency hopping", International
    Defense Review, May 1982.
United States Marine Corps, Command and Control Master Plan,
    Headquarters United States Marine Corps, March 1983.
Van, P.E., "New Concepts in Battlefield Communications Part
    1 - fast frequency hopping", International Defense
    Review, March 1982.

Join the GlobalSecurity.org mailing list