Radio operators handbook usmc

Wet cell batteries do not hold their charge efficiently in intense. Electrolyte evaporates rapidly and should be checked weekly more often, if warranted. Add distilled water as needed. Extra containers of distilled water should be carried in the vehicle.

Maintenance of vehicle batteries, beyond adding water, must be done only by authorized motor-transport personnel according to applicable Marine Corps Orders and SOPs. Dry battery supplies must be increased, since hot weather causes batteries to fail more rapidly. Wind-blown sand and grit will damage electrical wire insulation over a period of time. All cables that are likely to be damaged should be protected with tape before insulation becomes worn.

Carry a brush, such as an old toothbrush, and use it to clean such items before they are joined. Electrical Insulation. In deserts with relatively high dew levels and high humidity, overnight condensation can occur wherever surfaces such as metals exposed to air are cooler than the air temperature. This condensation can affect electrical plugs, jacks, and connectors.

All connectors likely to be affected by condensation should be taped to prevent moisture from contaminating the contacts. Plugs should be dried before inserting them into equipment jacks. Excessive moisture or dew should be dried from antenna connectors to prevent arcing. Static Electricity. Static electricity is prevalent in the desert. It is caused by many factors, e. Extremely low humidity contributes to static discharges between charged particles. Poor grounding conditions exacerbate the problem.

Be sure to tape all sharp edges tips of antennas to cut down on wind-caused static discharges and the accompanying noise. If you are operating from a fixed position,.

Since static-caused noise diminishes with an increase in frequency, use the highest frequencies that are available and authorized. Maintenance Improvement In desert areas, the maintenance of SCRs becomes more difficult because of the large amounts of sand, dust, or dirt that enter the equipment. Radios equipped with servomechanisms are particularly affected.

To reduce maintenance downtime, keep the radios in dustproof containers as much as possible. It is also important to keep air vent filters clean to allow cool air to circulate to prevent overheating.

Preventive maintenance checks should be made frequently. Also, keep a close check on lubricated parts of the equipment. If dust and dirt mix with the lubricants, moving parts may be damaged. However, since SCR can be deployed in many configurations, especially manpacked, it is a valuable communications asset. Mobility is also an advantage of SCR. The capabilities and limitations of SCR must be carefully considered when used by forces in a jungle environment.

Climate and density of jungle growth limits SCR communications in jungle areas. The hot and humid climate increases the maintenance problems of keeping equipment operable. Thick jungle growth acts as a vertically polarized absorbing screen for RF energy that reduces transmission range. Therefore, increased emphasis on maintenance and antenna siting is necessary when operating in jungle areas. Techniques for Operations The main problem in establishing SCR communications in jungle areas is the siting of the antenna.

Antennas should be located in clearings on the edge farthest from the distant station and as high as possible. Antenna cables and connectors should be kept off the ground to lessen the effects of moisture, fungus, and insects. This also applies to all power and telephone cables. Complete antenna systems, such as ground planes and dipoles, are more effective than fractional wavelength whip antennas.

Vegetation must be cleared from antenna sites. If an antenna touches any foliage, especially wet foliage, the signal will be grounded. Vegetation, particularly when wet, acts like a vertically polarized screen and absorbs much of a vertically polarized signal. Horizontally polarized antennas are preferred to vertically polarized antennas. Maintenance Improvement Because of moisture and fungus, the maintenance of SCR in tropical climates is more difficult than in temperate climates. The high relative humidity causes condensation to form on the equipment and encourages the growth of fungus.

Operators and maintenance personnel should check the appropriate TMs for any special maintenance requirements. Keep the equipment as dry as possible and in lighted areas to retard fungus growth. Keep all air vents clear of obstructions so air can circulate to cool and dry the equipment. Keep connectors, cables, and bare metal parts as free of fungus growth as possible.

Use moisture fungusproofing paint MFP to protect equipment after repairs are made or when equipment is damaged or scratched.

High Frequency Expedient Antennas Dismounted patrols and units of company size and below can greatly improve their ability to communicate in the jungle by using expedient antennas. While moving, they are generally restricted to using the short and long antennas which come with the radios. However, when they are not moving, these expedient antennas will allow them to broadcast farther and receive more clearly.

Whips are not as effective as a tuned doublet or tuned ground-plane, but the doublet or ground-plane must be tuned to the operating frequency. However, in spite of significant limitations, SCR is the normal means of communications in such areas. One of the most important capabilities of SCR in cold weather areas is its versatility. Vehicular-mounted radios can be moved relatively easily to almost any point where it is possible to install a command headquarters.

Smaller, manpacked radios can be carried to any point accessible by foot or aircraft. A limitation on radio communications that radio operators must expect in extremely cold areas is interference by ionospheric disturbances. These disturbances, known as ionospheric storms, have a definite degrading effect on sky wave propagation.

Moreover, either the storms or the auroral e. Some frequencies may be blocked out completely by static for extended periods of time during storm activity. Fading, caused by changes in the density and height of the ionosphere, can also occur and may last from minutes to weeks. The occurrence of these disturbances is difficult to predict. When they occur, the use of alternate frequencies and a greater reliance on FM or other means of communications are required. Techniques for Operations Whenever possible, SCR for tactical operations in cold weather areas should be installed in vehicles to reduce the problem of transportation and shelter for operators.

This will also help solve some of the grounding and antenna installation problems caused by the climate. Because of permafrost and deep snow, it is difficult to establish good electrical grounding in extremely cold areas. The conductivity of frozen ground is often too low to provide good ground wave propagation. To improve ground wave operation, use a counterpoise to offset the degrading effects of poor electrical ground conductivity. Remember to install a counterpoise high enough above the ground so that it will not be covered by snow.

In general, antenna installation in arcticlike areas presents no serious difficulties. However, installing some antennas may take longer because of adverse working conditions. Mast sections and antenna cables must be handled carefully since they become brittle in very low temperatures. Antenna cables should be constructed overhead to prevent damage from heavy snow and frost, whenever possible.

Nylon rope guys, if available, should be used in preference to cotton or hemp because nylon ropes do not readily absorb moisture and are less likely to freeze and break. Antennas should have extra guy wires, supports, and anchor stakes to withstand heavy ice and wind loading. Some Marine Corps radios that are adjusted to a particular frequency in a relatively warm place may drift off frequency when exposed to. Low battery voltage can also cause frequency drift. When possible, allow a radio to warm up several minutes before placing it into operation.

Since extreme cold tends to lower output voltage of a dry battery, try warming the battery with body heat before operating the radio set. This minimizes frequency drift.

Flakes or pellets of highly electrically charged snow are sometimes experienced in northern regions. When these particles strike the antenna, the resulting electrical discharge causes a high-pitched static roar that can blanket all frequencies. To overcome this static, antenna elements can be covered with polystyrene tape and shellac. Radios must be protected from blowing snow, since snow will freeze to dials and knobs and blow into the wiring to cause shorts and grounds.

Cords and cables must be handled carefully since they may lose their flexibility in extreme cold. All radio equipment and power units must be properly winterized. Check the appropriate technical manual TM for winterization procedures.

A few tips for maintenance in arctic areas are discussed in the following paragraphs. Power Units. As the temperature goes down, it becomes increasingly dif-. They should be protected as much as possible from the weather.

The effect of cold weather on wet and dry cell batteries depends upon the type and kind of battery, the load on the battery, the particular use of the battery, and the degree of exposure to cold temperatures. Damage may occur to vehicular SCR by the jolting of the vehicle. Most synthetic rubber shock mounts become stiff and brittle in extreme cold and fail to cushion equipment.

Check the shock mounts frequently and change them, as required. Shock Damage. Check the TMs for the SCR and power source to see if there are special precautions for operation in extremely cold climates. For example, normal lubricants may solidify and permit damage or malfunctions. They must be replaced with the recommended arctic lubricants. Moisture from your breath may freeze on the perforated cover plate of your microphone.

Use standard microphone covers to prevent this. If standard covers are not available, improvise a suitable cover from rubber or cellophane membranes or from rayon or nylon cloth. A SCR generates heat when it is operated. When it is turned off, the air inside cools and contracts and draws cold air into the set from the outside.

This is called breathing. When a radio breathes, and the still-hot parts come in contact with subzero air, the glass, plastic, and ceramic parts of the set may cool too rapidly and break. Breathing and Sweating. When cold equipment is brought suddenly into contact with warm air, moisture will condense on the equipment parts. This is called sweating.

Before cold equipment is brought into a heated area, it should be wrapped in a blanket or parka to ensure that it will warm gradually to reduce sweating. Equipment must be thoroughly dry before it is taken back out into the cold air or the moisture will freeze. Vehicular-Mounted Radios. These radios present special problems during.

Proper starting procedures must be observed. If the radio is cold soaked from prolonged shutdown, frost may have collected inside the radio and could cause circuit arcing. Hence, time should be allowed for the vehicle heater to warm the radio sufficiently that any frost collected within the radio has a chance to thaw.

This may take up to an hour. Once the radio has been turned on, it should warm up for approximately 15 minutes before transmitting or changing frequencies. This allows components to stabilize. If a vehicle is operated at a low idle with radios, heater, and lights on, the batteries may run down.

Before increasing engine revolutions per minute to charge the batteries, radios should be turned off to avoid an excessive power surge. A light coat of silicon compound on. Also, the mountainous terrain makes the selection of transmission sites a critical task.

In addition, the terrain restrictions encountered frequently make radio relay stations necessary for good communications. Maintenance Improvement Because of terrain obstacles, SCR transmissions will frequently have to be by line of sight. Also, the ground in mountainous areas is often a poor electrical conductor.

Thus, a complete antenna system, such as a dipole or ground-plane antenna with a counterpoise, should be used. The maintenance procedures required in mountainous areas are very often the same as maintenance in northern or cold weather areas. The varied or seasonal temperature and climatic conditions in mountainous areas make flexible maintenance planning a necessity.

Some problems are similar to those encountered in mountainous areas. There are problems of obstacles blocking transmission paths. There is the problem of poor electrical conductivity because of pavement surfaces.

There is also the problem of commercial power-line interference. VHF radios are not as effective in urbanized terrain as they are in some other areas.

The power output and operating frequencies of these VHF radios require a line of sight between antennas. Line of sight at street level is not always possible in built-up areas. HF radios do not require or rely on line of sight as much as VHF radios because operating frequencies are lower, and power output is greater. The problem is that HF radios are not organic to small units. To overcome this, the VHF signals must be retransmitted. Retransmission stations in aerial platforms can provide the most effective means if they are available.

Organic retransmission is more likely to be used. The antenna should be hidden or blended in with surroundings. Antennas can be concealed by water towers, existing civilian antennas, or steeples. The following steps should also be taken within urbanized terrain: l. Park radio-equipped vehicles inside buildings for cover and concealment.

Dismount radio equipment and install it inside buildings in basement, if available. Place generators against buildings or under sheds to decrease noise and provide concealment adequate ventilation must be provided to prevent heat buildup and subsequent failure of generator. Nuclear, Biological, and Chemical Environment One of the realities of fighting on the modern battlefield is the presence of nuclear weapons.

The explosion of a nuclear weapon causes a tremendous blast, followed by intense heat and strong radiation. The ionization of the atmosphere by a nuclear explosion will have degrading effects on communications because of static and the disruption of the ionosphere. Another effect of a nuclear explosion that is an even greater danger to radio communications is the electromagnetic pulse EMP.

EMP is a strong pulse of electromagnetic radiation, many times stronger than the static pulse generated by lightning. This pulse can enter the radio through the antenna system, power connections, and signal input connections. In the equipment, the pulse can break down circuit components such as transistors, diodes, and integrated circuits. It can melt capacitors, inductors, and transformers. EMP can destroy a radio.

Defensive measures against EMP call for proper maintenance, particularly the shielding of equipment. When the equipment is not in use, all antennas and cables should be removed to decrease the effect of EMP on the equipment. Effective grounding is necessary to reduce effect of EMP. Contamination from any portion of the nuclear, biological, and chemical NBC environment has adverse effects on both equipment and personnel.

Electronic Warfare Electronic warfare EW is the military action involving the use of electromagnetic energy i. EP represents actions taken to protect personnel, facilities, and equipment from any effects of friendly or enemy employment of electronic warfare that degrade, neutralize, or destroy friendly combat capability.

ES involves actions taken by, or under direct control of, an operational commander to search for, intercept, identify, and locate sources of intentional or unintentional radiated electromagnetic energy for the purpose of immediate threat recognition. Each radio operator must be aware of what the enemy will try to do. When the enemy locates sites that the enemy cannot or does not want to destroy, these sites become prime targets for imitative electronic deception IED or jamming.

The enemy IED experts are very good at their jobs. If they are permitted to enter into a net, they will create much confusion for friendly forces. Jamming is an effective way to disrupt control of the battle. All it takes is a transmitter, tuned to your frequency, with the same type of modulation and with enough power output to override the signal at your receiver. There are many types of jamming signals that may be used against a radio operator.

Some are very difficult to detect and some are impossible to detect. For this reason, an operator must always be alert to the probability of jamming and react accordingly when the radio has been silent for an inordinate amount of time. The radio operator should also be able to quickly identify the various types of jamming signals. Random noise. Random pulse. Stepped tones. Random keyed modulated continuous wave. Recorded Sounds.

Capture Effect and Jamming Techniques An inherent characteristic in FM communications is that a given station transmitting a signal will capture those receivers on the same frequency and in range for the receiver to detect the signal. This could be friendly interference or enemy interference.

Friendly interference is usually unintentional whereas enemy interference is usually intentional. Obvious Jamming Radio operators are mostly aware of obvious interference e.

The purpose of this type of jamming is to block out reception of friendly transmitted signals and to cause a nuisance to the receiving operator. An operator can usually detect when the enemy is using this type of jamming.

Subtle Jamming This type of jamming is not obvious at all. With subtle jamming, no sound is heard from the receiver. The radio does not receive incoming friendly signals, yet everything seems normal to the operator. Operator Actions Radio operators must be able to determine whether or not their radios are being jammed. This is not always easy. Threat jammers may employ obvious or subtle jamming techniques.

Unmodulated jamming signals are characterized by a lack of noise. Noise-modulated jamming signals are characterized by obvious interference noises. If radio operators suspect that their radios are the targets of threat jamming, the following procedures will help them to make this determination. Meaconing, Intrusion, Jamming, and Interference Report If the radio operator suspects jamming or enemy intrusion on the net, then the radio operator should report it immediately to higher headquarters.

Such information is vital for the protection and defense of radio communications. Field meaconing, intrusion, jamming, and interference MIJI reports serve two purposes. Second, complete and accurate followup reports ensure MIJI incidents are documented and evaluated on a. MIJI reports may be transmitted over nonsecure electronic means when secure communications are not available; however, the textual content of the MIJI report will be secured by an off-line i.

Reports will be prepared in the format outlined in the following paragraphs. Brevity numbers pertinent to specific line item information are provided for some items. These brevity numbers must be encoded in the numeral cipher or authentication system prior to transmission.

The two types of field MIJI reports are— l. MIJI 1—an abbreviated initial report containing only those items of information necessary to inform headquarters of the incident and enable them to initiate evaluatory or retaliatory actions as appropriate. MIJI 2—consists of 40 lines and is completed by higher headquarters. This report is forwarded through the chain of command to the combat operations center by the operator who is experiencing the MIJI incident.

A separate report is submitted for each MIJI incident. The MIJI report includes— l. Item 1—type report. When being transmitted over nonsecure communications means, the numerals are encrypted as Item 1 of the MIJI 1 report.

Item 2—type MIJI incident. When being transmitted over nonsecure communications means, the appropriate numeral preceding one of the items below is encrypted as Item 2 of the MIJI 1 report. When being transmitted over secure communications means, the appropriate term below is used as Item 2 of the MIJI 1 report. Item 3—type of equipment affected. When being transmitted over nonsecure communications means, the appropriate numeral preceding one of the terms below is encrypted as Item 3 of the MIJI 1 report.

When being transmitted over secure communications means, the appropriate term below is used as Item 3 of the MIJI 1 report. Item 4—Frequency or channel affected. Item 5—victim designation and call sign of affected station operator. The complete call sign of the affected station operator is Item 5 of the MIJI 1 report over both secure and nonsecure communications means.

Item 6—coordinates of the affected station. When being transmitted over nonsecure communications means, the complete grid coordinates of the affected station are encrypted as Item 6 of the MIJI 1 report. When being transmitted over secure communications means, the complete grid coordinates of the affected station are Item 6 of the MIJI 1 report.

This is a complete report containing all details of the MIJI incident. Due to the number of items which require encryption when the report is transmitted over a nonsecure circuit, it is recommended that the report be delivered by messenger whenever possible.

COMSEC is the protection resulting from all measures designed to deny unauthorized persons information of value that might be derived from the possession and study of telecommunications or to mislead unauthorized persons in their interpretation of the results of such possession and study.

The goal of COMSEC is to protect friendly communications from enemy exploitation while ensuring unimpeded use of the electromagnetic spectrum. The organization must be able to employ communications equipment effectively in the face of enemy efforts.

COMSEC requirements must be integrated into communications systems planning and must focus on providing secure communications without impairing reliability or responsiveness. Modern communications equipment includes features such as an integrated encryption capability and frequency hopping capability, which contribute to communications protection. However, the security of our communications depends on the proper operation of communications equipment and adherence to proper procedures.

The enemy hopes to learn essential elements of friendly information EEFI. Strength—number of personnel, size of unit. Equipment—type, quantity, condition. Logistics—procedure for resupply, depots.

Disposition—were, what positions, map coordinates. Organization—how, what, chain of command, forces structure. Movement and morale—where, how, when and good or bad. Units—type, designation. Personalities—who, where. When the radio must be used, keep transmission time to an absolute minimum 20 seconds absolute maximum: 15 seconds maximum preferred ; preplan your messages to avoid compromising any essential element of information.

If you must send EEFI items, use brevity lists, if possible, and also encrypt the message. These measures decrease your transmission, help prevent RDF, and deny the enemy valuable information.

Every radio operator must be aware of the dangers of and guard against IED. Well-trained operators thoroughly familiar with proper communications procedures and equipment operation. Avoidance of unauthorized transmission and testing and maximum use of data networks to minimize transmission time and opportunity for enemy direction finding. Use of transmitter, antenna, and power combinations that produce minimum wave propagation and emission intensity consistent with reliable communications.

All they had to do was aim for the antenna and they could wipe out anyone near the radio operator. As terrible as it sounds, this meant that the radio operator would sometimes move in isolation, away from the rest of the squad.

While many radio operators were fulfilling their MOS, others just had a radio strapped to them in times of need. One thing is for certain, though: Being a radio operator back in the Vietnam War puts you among the most badass troops the military has to offer. To hear one of these badasses explain what life was like in his own words, check out the video below.

Measure content performance. Develop and improve products. List of Partners vendors. Careers Marine Jobs. By Stewart Smith. Learn about our editorial policies. Your Privacy Rights. To change or withdraw your consent choices for TheBalanceCareers. When using a quarter-wave or whip antenna, ground the antenna to increase its effectiveness.

Using this characteristic of the ground, an antenna a quarter-wavelength long can be made into the equivalent of a half-wave antenna. If such an antenna is erected vertically and its lower end is grounded, the ground takes the place of the missing quarter-wavelength, and the reflections supply that part of the radiated energy normally supplied by the lower half of an ungrounded half-wave antenna.

The antenna is grounded by grounding the vehicle itself. Use a ground stake at least 4 feet long, a hammer, and a ground strap. You may substitute a steel reinforcing rod, a steel fence poet, or a metal water or gas pipe cut to the right length for the ground stake. Ensure paint and rust are removed from such items. Substitutes for the ground strap include battery cables or any heavy gauge wire.

Do not use Field Wire WD-1 because it does not provide a suitable ground. Drive the ground stake into the ground until the top of the stake is 2 to 4 inches above the ground. Attach one end of the ground strap to the stake and the other end to the vehicle body. Ensure all paint and rust are removed from connecting point of the vehicle body to allow a good metal-to-metal contact.

When a whip antenna is mounted on a vehicle, the metal of the vehicle will affect the operation of the antenna. As a result, the direction in which the vehicle is facing may also affect transmission and reception, particularly of distant or weak signals. A vehicle with a whip antenna mounted on its left rear side transmits its strongest signal in a line running diagonally from the antenna through the right front side of the vehicle.

Similarly, an antenna mounted on the right rear side of the vehicle radiates its strongest signal in a direction diagonally toward the left front side. In some cases, the best direction can be determined by driving the vehicle in a small circle until the best reception is obtained.

Antenna RC is used to extend the distance range of the old and new generation of FM field radio sets. The antenna consists of one vertical radiating element and three ground plane elements. The lengths of these elements are determined by the operating frequency of the radio set.

Refer to the antenna element selection chart at Table The antenna is elevated on a foot sectional mast which in turn is held erect by guy ropes and stakes. When the operating frequency is changed, check the antenna element selection chart.

If the new frequency requires a change in element length, lower the antenna and add or subtract the required number of elements. The antenna consists of three upward and three downward extended radials. These radials remain the same length for all frequencies from 30 to 88 MHz. The antenna is elevated on a foot sectional mast held erect with guy ropes and stakes.

NOTE: No change needs to be made in the number of radials when a change of frequency is necessary.