18
Radio Sets, Procedures, and Field Antennas
Radios, the most common means of military communication, are particularly suited for use when you are on the move. Small handheld or backpack radios that communicate for only short distances are found at squad and platoon levels. As the need grows to talk over greater distances and to more units, the size and complexity of radios increase.
From brigade level to the squad level, the Army primarily uses FM (frequency modulating) single-channel radios as its primary means of communication. The FM radio has a range of approximately 35 to 40 kilometers, which covers a brigade/battalion maneuver area. FM radio transmissions are normally line-of-sight (LOS), so large terrain features can block transmission.
ENVIRONMENT
Factors that affect the range of radios are weather, terrain, power, antenna, and the location of the radio. Manmade objects such as bridges and buildings may affect radio transmission. Interference may also come from power lines, electrical generators, other radio stations, and enemy jamming. You can correct many of the causes of poor radio communications by using common sense. For example, make sure you are not trying to communicate from under a steel bridge.
RULES FOR RADIO USE
Observe the following rules for radio use:
•Listen before transmitting.
•Avoid excessive radio checks.
•Make messages clear and concise. If possible, write them out before transmitting.
•Speak clearly, slowly, and in natural phrases, enunciating each word. If the receiving operator must write, allow time for writing.
•Always assume the enemy is listening.
•If jammed, notify higher headquarters by established procedures.
•Maintain whip antennas in a vertical position.
•Make sure the radio is turned off before starting a vehicle.
PROWORDS
Common prowords are those words that are used on a regular basis while conducting radio operations. Prowords are not interchangeable, as the meanings are specific and clear to the receiver. An example is “Say again” versus “Repeat.” “Say again” means to repeat the last transmission, while “Repeat” means to fire the last artillery fire mission again. The following are frequently used prowords:
All after—I refer to the entire message that follows . . .
All before—I refer to the entire message that precedes . . .
Break—I now separate the text from other parts of the message.
Correction—There is an error in this transmission. Transmission will continue with the last word correctly transmitted.
Groups—This message contains the number of groups indicated by the numeral following.
I say again—I am repeating transmission or part indicated.
I spell—I shall spell the next word phonetically.
Message—A message that requires recording is about to follow (transmitted immediately after the call). Note: This proword is not used on nets primarily employed for conveying messages. It is intended for use when messages are passed on tactical or reporting net.
More to follow—Transmitting station has additional traffic for the receiving station.
Out—This is the end of my transmission to you and no answer is required or expected.
Over—This is the end of my transmission to you and a response is necessary. Go ahead: transmit.
Radio check—What is my signal strength and readability, i.e. how do you hear me?
Roger—I have received your last transmission satisfactorily, radio check is loud and clear.
Say again—Repeat all of your last transmission. Followed by identification data means “repeat—(portion indicated).”
This is—This transmission is from the station whose designator immediately follows.
Time—That which immediately follows is the time or date-time group of the message.
Wait—I must pause for a few seconds.
Wait-out—I must pause longer than a few seconds.
Wilco—I have received your transmission, understand it, and will comply, to be used only by the addressee. Note: Since the meaning of “Roger” is included in that of WILCO, the two prowords are never used together.
Word after—I refer to the word of the message that follows.
Word before—I refer to the word of the message that precedes.
SECURITY
Radio is one of the least secure means of communicating. Each time you talk, your voice travels in all directions. The enemy can listen to your transmissions to get information about you and your unit, or to locate your position to destroy you with artillery fire. Communications security keeps unauthorized persons from gaining information of value from radio and telephone transmissions. It includes the following:
•Using authentication to make sure that the other communicating station is a friendly one.
•Using only approved codes.
•Designating periods when all radios are turned off.
•Restricting the use of radio transmitters and monitoring radio receivers.
•Operating radios on low power.
•Enforcing net discipline and radiotelephone procedure (all stations must use authorized prosigns and prowords and must transmit official traffic only).
•Using radio sites with hills or other shields between them and the enemy.
•Using directional antennas when feasible.
RADIO SETS AND RECEIVER-TRANSMITTERS
SINCGARS Ground Combat Net Radio
The bulk of US Army Active and Reserve Component forces are likely to be supplied with one or more versions of the single-channel ground and airborne radio (SINCGARS). The older versions are the Receiver-Transmitter (RT) 1523A/B models. The newer versions are the SIP (Systems Improvement Program) ground combat radio RT-1523C/D models and the even newer SINCGARS ASIP (Advanced Systems Improvement Program) ground combat radio or RT-1523E model. These RT-1523A–D radio systems look very much alike, but the newer version has better technology for electronic warfare and better data transfer rates.
The newer SINCGARS ASIP is a user-owned-and-operated solid-state frequency modulated (FM) combat net radio (CNR). It operates in the 30.000 to 87.975 MHz frequency range in the single-channel (SC) or frequency-hopping (FH) mode. The ASIP replaces the RT-1523A and RT-1523B model SINCGARS. The ASIP is compatible with the older SINCGARS and with NATO forces in SC, squelch-off mode. It provides electronic warfare (EW) protection and a reduced electromagnetic signature in the FH mode. Maintenance procedures are the same for the older SINCGARS radio. The SINCGARS has eight preset channels in SC mode and six for FH mode. The cue and manual frequencies are included in the eight single-channel frequencies. It is designed for secure voice and data communications and is an antijam radio. The individual components are interchangeable from one radio to the next.
As mentioned above, the primary component of the SINCGARS is the receiver-transmitter or RT-1523 Series A through E. The RT-1523 series and necessary additional components make up either a dismounted or a mounted configuration. The radio appearance of the RT-1523 Series A–D is basically the same (see figure). The front panels and keyboards for the RT-1523 Series differ depending on the versions (see figures).