Field Communications
Objectives
Upon completion of this course the student will have a good working
knowledge of the following:
– Types of communications methods of field communications.
– Types of communications nets
– Operating characteristics of the five common field radios.
– Proper radio procedure
– Net security procedures
Introduction
• Without an effective communication system, any combat,
logistics, support or training mission will suffer due to the
lack of coordination and flow of timely information.
• It is the radio operators/supervisors responsibility to
ensure that your site has operational radios and that they
are familiar with their operation. If any problems exists it
is imperative that the radio operator/supervisor contact
the supporting SLIC unit for repairs.
Definitions
• Transmission – A communication sent by one station and intended
for reception by another station or stations.
• Answer – A transmission made by a station called in response to a
call received.
• Receipt – A communication sent by the received operator indicating
that the message or transmission has been satisfactorily received.
• Acknowledgment – A separate message originated by the
addressee that will inform the originator that the message has been
received and is understood.
• Net – An abbreviation for network. In reference to communications,
it normally means a group of stations or radio operators on the same
frequency.
Fundamental Requirements Of An
Effective Communications System
• The following are fundamentals of effective communications
systems without which the system will degrade command and
control:
– Reliability – The use of proven communications techniques and
equipment by Trained operators.
– Security – Protection of information passed over a communications
network.
– Speed – The time it takes the message to get from the writer to the
intended receiver.
– Flexibility – The ability to support a wide dispersion of units under
adverse and varying conditions.
Types of Communications
• Communication methods vary from sending a runner to the most
sophisticated satellite communications
• Messenger – The most secure method of relaying communications.
• Telephone – Normally non-secure, available for unclassified
communications. During training exercises is available for actual
emergencies.
• Hand-held Radios – Used for shipboard communications and
normally limited to short-range communications. Classified
transmissions are not authorized.
Types of Communications
(cont.)
• Hand-held Radios (Cont.)
– There are two basic configurations
• Hazardous Electromagnetic Radiological Ordnance (HERO) Safe – A
green dot will appear on the radio and the battery indicating they are
HERO safe. If either the radio or the attached battery does not display
a green dot, the radio is not HERO safe. It is the only radio authorized
for use while operating around or near ammunition.
• Standard (Non-HERO Safe) – A red dot will appear on the radio and on
the battery indicating they are not HERO safe. These radios are not
authorized for use around or near ammunition.
– Radios with no marking or a mixture of red and green markings are
considered Non-HERO safe.
• Field Radios – Portable, heavy duty two way radios used for
communication in the field. Field radios vary with branch of service
and selected use.
Hand-Held Radio Uses
• There are only two hand-held radios used for cargo handling:
– Motorola XTS5000R
• UHF or VHF Frequency Ranges – Dependent on factory configuration.
• Secure or Non-Secure
– The Non-Secure model is the primary version used by Cargo Handling units.
– Secure models are identified by the CCI marking located on the bottom of the
radio.
– AN/PRC-148 (MBITR/JEMS)
• Primarily used for tactical communications for short range communications.
• Not commonly used for shipboard operations due to the need of an auxiliary
headset device to allow user to hear communications.
• Compatible with Marine Band Radios.
• UHF Satellite voice communications capable.
General Field Radio Uses
• AN/PRC-119 (RT-1523)
– Line-of-Sight (LOS) VHF voice communications.
– SINCGARS (Single Channel Ground Airborne Radio System)
capable.
• AN/PRC-150 (RT-1694)
– Beyond Line-of-Sight (BLOS) voice and data communications.
– HF and VHF (Low) Frequency Range.
• AN/PRC-117 (RT-1796)
– Line-of-Sight (LOS) VHF and UHF voice and data
communications.
– SINCGARS (Single Channel Ground Airborne Radio System)
capable.
– UHF Satellite voice and data communications.
AN/PRC-119 General Characteristics
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Single Channel (SC) or Frequency Hopping modes of operation.
System Presets:
– 8 in Single Channel (SC) mode
– 6 in Frequency Hopping (FH or FHM) mode
• ECCM – Electronic Counter Countermeasures
– 6 COMSEC storage positions.
VHF Line Of Sight (LOS) radio operates in frequency range of 30.000 87.975 MHz (note: Frequencies must in in 25 KHz increments).
Embedded Type-1 COMSEC
Can be carried in a Manpack or installed in a Vehicle or Basestation
mounts.
Average battery life 16-18 hours using re-chargeable battery.
Can be used for stationary operation using an external power supply.
AN/PRC-150 General Characteristics
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Two radios in one box
– HF-SSB (USB) Radio for Beyond Line-of-Sight (BLOS)
– VHF-FM for Line-of-Sight (LOS)
Frequency Range: 1.6 - 59.9999 MHz
Four Basic Modes of Operation:
– FIX
– HOP (Not Used)
– ALE (Automatic Link Establishment)
– 3G (3rd Generation ALE)
Embedded Type-1 COMSEC
Automatic Tuning Coupler
Analog or Digital Voice and Data
Remote programmable through Remote Programming Application (RPA)
software. COMSEC must be loaded separately.
Uses connection via laptop computer to provide Outlook based message
capability using Wireless Messaging Terminal (WMT) software.
Text messaging capability using AMD (Automatic Message Display) feature in
ALE and 3G modes.
Can be carried in Manpack or used in either vehicle mount or basestation.
Can be connected to external GPS devices for time of day information.
AN/PRC-117 General Characteristics
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VHF/UHF Line-of-Sight voice and data communications.
UHF SATCOM Dedicated or DAMA Wideband and Narrowband voice and data.
Frequency Range: 30-512 MHz
SINCGARS (Single Channel Ground Airborne Radio System) capable.
HAVEQUICK capable.
Remote programmable through Remote Programming Application software or
radio cloning cable. COMSEC must be loaded separately.
Can be connected to external GPS devices for time of day information and
situational awareness information.
Embedded Type-1 COMSEC
Analog or Digital Voice
Voice and Data capable
Remote programmable through Remote Programming Application (RPA)
software. COMSEC must be loaded separately.
Uses connection via laptop computer to provide Outlook based message
capability using High Performance Waveform (HPW) software.
Can be carried in Manpack or used in either vehicle mount or basestation.
Field Radios
AN/PRC-119
AN/PRC-150
AN/PRC-117
Compatible Fill Devices
• AN/CYZ-10 Data Transfer Device (DTD)
• KYX-15
• KYK-13
• KOI-18
Prowords
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ALL AFTER – Used to request a repeat of a portion of a message that was missed
after a certain word or phrase.
ALL BEFORE – Used to request a repeat of a portion of a message that was missed
before a certain word or phrase.
BREAK – Indicates the separation of the text from other portions of the message and
when communicating to more than one site if there is a different message to transmit.
CORRECTION – An error has been made in the transmission. Continue with the last
word transmitted correctly.
I SAY AGAIN – I am repeating this transmission or portion indicated. Normally used
when very important information is being passed or communications are difficult.
I SPELL – Spell the next word phonetically. Used when communications are difficult.
OUT – This is the end of the transmission and no answer or reply is required or
expected.
OVER – This is the end of the transmission and a response is necessary.
WAIT – Indicates a pause for a few seconds.
WAIT OUT – Indicates a pause for longer than a few seconds.
ROGER – I have received the last transmission satisfactorily.
Phonetic Alphabet
A
B
C
D
E
F
G
H
I
Alpha
Bravo
Charlie
Delta
Echo
Foxtrot
Golf
Hotel
India
J Juliet
K Kilo
L Lima
M Mike
N November
O Oscar
P Papa
Q Quebec
R Romeo
S
T
U
V
W
X
Y
Z
Sierra
Tango
Uniform
Victor
Whiskey
X-Ray
Yankee
Zulu
Call Signs
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Call Signs – Words, combinations of words, or a combination of phonetic
alphabet letters intended to identify the command, unit, or authority of the
radio caller.
CALL SIGN USAGE:
Calling a single station – First, say the call sign (name) of the station you are
calling, then say the call sign (name) of your station (Station called, station
calling).
– Example – “Hotel Foxtrot, this is Mike Papa”
Collective Call Signs – A call sign designated to represent all stations on the
net. When a collective call sign is used, all stations on the net report back
in alphabetical order.
– Example – (Your call sign is GT - other stations AB, CG, and JU – collective call
sign is HN)
Transmission: “Hotel November, this is Golf Tango, radio check, over”
Replies:
“Alpha Bravo, Lima Charlie” “Charlie Golf, Lima Charlie”
“Juliet Uniform, Lima Charlie”
Types of Radio Nets
• There are two different types of radio nets:
– Free Net – The NECOS authorizes member stations to transmit
traffic to other stations without obtaining clearance from NECOS.
– Directed Net – Member stations must obtain permission from
NECOS before communicating with other stations.
• Net Control Station (NECOS) – The Net Control Station (NECOS)
is the radio station that has command responsibility for all
transmission taking place on a designated net.
• Frequencies – A minimum of three frequencies will be designated
by NECOS prior to bringing a net on-line. Due to the nature of HF
communications frequencies will be designated by the local area
commander, for your specific operating area. The Communications
Officer (N6) will determine any VHF or UHF frequencies to be used.
• Guard Shifts:
– A minimum of three frequencies, authentication tables, and call
signs are assigned per guard shift. A guard shift occurs when
NECOS notifies all stations on a net to change frequencies,
authentication tables, and call signs at a designated time, normally
once every 24 hours.
– Only NECOS may initiate a guard shift; however, any station may
execute a change in the call signs or frequencies with just cause
(suspicion of enemy activity on the net).
Communications Log (Comm Log)
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All stations on the net will keep an accurate Comm Log unless
otherwise directed. Comm Logs contain two main parts, the heading,
which contains all information pertaining to the net, and the body,
which contains information passed on the net.
– Heading – The information contained in the heading will include:
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Circuit – The designated net or circuit for which the log is being maintained.
Frequency – The designated Frequency on which the net is operating.
Operator – The name of the operator who maintains the comm log.
Supervisor – The name of the individual who is directly responsible during the watch.
Station Call – The station call sign for which the log is being maintained.
NECOS – The actual name of the station, not the call sign.
Net Call Sign – The collective call sign for the net.
Page – The page number of the log.
– Body – Contains a chronological log of all events that take place on the net.
• Every transmission heard by an operator on watch, regardless of source or
completeness, shall be recorded.
• The operator and supervisor at the end of each shift will sign the log.
• Log pages will be ended and a new page started after each frequency shift, call sign
shift, or authentication table shift.
Types of Interference
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Jamming:
– Jamming is an action taken to intentionally block or interfere with radio transmissions. The
enemy may jam radio signals by transmitting a stronger signal on the frequency, making it
difficult or impossible to hear the desired signal
– Unusual noises or strong interference on the receiver may be enemy jamming. This,
however, should not be confused with poorly transmitted signals from a friendly station, noise
from a local source, or a defective receiver.
– To determine if the interference is originating in the receiver, disconnect the antenna. If the
interference continues, the receiver is defective.
Anti-Jamming:
– When jamming of a channel is first noticed, notify the supervisor immediately and continue to
operate the equipment. To provide maximum clarity of jammed signals, perform the
following:
– Place the communications equipment so that nearby obstructions act as a screen in the
direction of probable sites of enemy jamming transmitters. This screening action may also
reduce transmitted signal strength toward the enemy and make it more difficult to intercept
signals.
• Vary the volume control. The level of the desired signal may be raised enough to be
distinguished from the jamming signal.
• Change to an alternate frequency.
• Change to an alternate call sign. Some stations may be closer than others therefore an
enemy may pick up one station prior to others.
Interference:
• Natural Interference: Atmospheric conditions that can interfere with radio transmissions
(i.e. sunspots, lightening, inclement weather).
• Man-made Interference: Mechanical or non-mechanical devices that due to operation
can cause interference with radio transmissions. Interference could range from light
static or low hum to a complete degradation of signal. Unlike jamming man-made
interference is not intentional and under most situations can be reduced or eliminated.
Security
Always assume that the enemy is listening and use correctly security procedures when
communicating classified information. Essential Elements Of Friendly Information (EEFI), includes
seemingly unimportant information that can be a valuable source of intelligence to the enemy.
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Radio Silence or Emergency Silence (Silence On The Net) - Any station having just cause can set
emergency radio silence. The unit or detachment Commanding Officer defines just cause.
– Normal reasons for radio silence include the compromise of classified information to the enemy, or the
endangerment of personnel or equipment.
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Beadwindow – Is a code that allows one station to notify another of a security breech that has occurred
over a circuit, and indicates to the transmitting station that he/she has violated security.
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Transmission - The proper procedure for calling a beadwindow is – “Beadwindow one (the
appropriate number), beadwindow one, beadwindow one”.
• If the appropriate beadwindow code is not known, beadwindow may be used by itself.
• If no response or the continued violation of a beadwindow exists continue to call a beadwindow
in an attempt to jam the circuit until the violation stops.
• The person transmitting can not hear the beadwindow being called unless a second handset or
an external speaker is installed; the handset only performs one function at a time.
Response – The only response to beadwindow is “Roger Out”.
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Beadwindow procedures are incorporated into a Communications Plan (COMM PLAN).
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Challenge and Reply: Used when enemy intrusion is suspected on the net. May also be used to confirm
friendly status of a calling station. Challenge and reply should conducted using authentication tables.
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Authentication Tables- Authentication tables are used to conduct challenge and reply validation of
friendly forces. Authentication tables should be changed daily and can be locally generated.
Beadwindow Table
00
01
02
The information requested, or about to be passed, will disclose an EEFI and
should be transmitted via secure means.
03
Movement, intent or location of any air, sea, or ground element, unit or force.
Example – Air squadron embarking/debarking a carrier.
04
05
06
07
08
09
11
Objectives or effectiveness of friendly or hostile deception or jamming.
Forewarning/foreknowledge of the time frame, participants or objectives of an
operation, mission, or exercise.
Capabilities, limitations of a force, ship, unit or special equipment.
Example – Unit or personnel casualty, amount of fuel/ammo on board.
Present or intended emission control (EMCON) plans or type of equipment
affected by a given EMCON condition.
Disclosure of enemy location or strengths.
Compromise of daily changing call signs.
Compromise of operations or numerical codes.
Plain language reference to frequency, or linkage of circuit designator with
either frequency or title.
VIP Movement during exercises or operations.