Incorrect choice of antenna device for tactical radio series R-168 or Harris instantly leads to a critical drop in the communication range and desynchronization of the frequency plan in the field. The operational environment dictates strict requirements for standing wave ratio (SWR) and polarization radiation pattern, since errors during the deployment phase can cost the life of a unit. Military radios operate in hostile environments where standard civilian solutions are often ineffective due to lack of EMP protection and mechanical strength.
Unlike civilian equipment, where compactness is often a priority, antennas for military radio stations are designed taking into account the need for quick camouflage and work on the move. The design must withstand shock loads during landing, immersion in water and extreme temperature changes from -50 to +60 degrees Celsius. Development engineers pay special attention to broadband, which allows them to cover several ranges at once without physically rearranging the elements.
The effectiveness of combat use directly depends on the compliance of the antenna type with the terrain and the tactical task, be it covert communication in a forest or providing a channel on an open plain. The use of an inappropriate emitter leads to the appearance of “dead zones” and the possibility of the enemy’s direction finding of the location of the command post. Below is a detailed analysis of the main categories of antenna systems used in modern armed forces.
Whip antenna systems and their modifications
The most common type at the tactical control level are whip antennas installed directly on the radio body or on the side of an armored vehicle. Construction monopole emitter allows you to quickly deploy communication on the move, but requires careful adjustment of the length of the pin to the operating frequency to minimize SWR. Modern models are often made telescopic or made of flexible materials, which reduces the risk of breakage when branching in the forest.
- 📡 Antenna ASh-10 — a basic telescopic model for portable radio stations, providing a circular radiation pattern.
- 📡 Flexible pin ASH-2 — resistant to bending, used on moving objects and in densely built-up conditions.
- 📡 Short antenna — has a load coil to reduce dimensions while maintaining the resonant frequency.
⚠️ Attention: When installing a whip antenna on a metal board of equipment, it is necessary to use a dielectric gasket or a magnetic base with grounding, otherwise the directional pattern will be distorted and the efficiency will drop to 40%.
To increase efficiency in the VHF band, composite pin systems consisting of several segments are often used. An important parameter is the electrical strength of the insulator, which must withstand a voltage of several kilowatts when the transmitter is operating at maximum power. Critical monitor the condition of the contact group of the base, as oxidation leads to signal loss and overheating of the connector.
Wire other antenna devices
In stationary conditions or when organizing temporary command posts, the greatest communication range is provided by wire antennas raised on trees, masts or special supports. Dipole and inclined configurations allow the formation of a narrowly directed beam towards the correspondent, which increases the noise immunity of the channel. The length of the canvas is calculated strictly according to the half-wave or quarter-wave formula, taking into account the shortening coefficient.
Calculation of the length of a wire antenna
The formula for calculating the length L (meters) = 150 / f (MHz) for a half-wave dipole. For a single wire grounded antenna the length is 75/f. It is necessary to take into account the height of the suspension, which must be at least 0.1 wavelength for effective radiation.
The use of an antenna tuner (matching device) allows you to expand the operating range of the same wire system. The operator can change the frequency of the radio station, and the automation will adjust the reactive elements, minimizing the reflected power. This is especially true for radios like R-168-100KNoperating in a wide sector of the HF range.
- 🌲 Slant beam - simple installation between two supports, good range, requires high lifting of one end.
- 🌲 Dipole — a symmetrical system, requires balancing, provides stable parameters over a wide frequency band.
- 🌲 Loop vibrator - has a high input impedance and a wide bandwidth compared to a simple dipole.
The material for the blade is most often bimetallic wire (copper-coated steel) or phosphor bronze, which provides high mechanical tensile strength. During installation, it is necessary to use insulators made of polyethylene or fluoroplastic, resistant to ultraviolet radiation and moisture. The tension of the wire must be controlled so that gusts of wind do not cause the supports to break or fall.
Directional antennas for long-distance communications
To organize backbone communication channels over long distances, complex directional antenna systems are used, such as wave channels and log-periodic structures. Antenna type "Wave channel" (Yagi) consists of an active vibrator, a reflector and several directors, which allows for a high gain. Such systems are indispensable when working in conditions of strong natural and artificial interference.
Log periodic antennas (LPAs) are a set of vibrators of different lengths connected to the power line through cross connections. Their main advantage is broadband, allowing them to cover ten-day frequency ranges without tuning. In military applications, this allows one antenna post to serve several radio networks simultaneously or quickly change frequency to avoid jamming.
The main advantage of directional antennas is the ability to increase the communication range by 3-5 times without increasing the transmitter power due to the concentration of radiation energy in a narrow sector.
Installation of such systems requires precise orientation to the azimuth of the correspondent and the use of durable mast structures. The wind load on the antenna windage can be significant, so the calculation of the foundation or guy wires is carried out with a safety margin. For the HF range, loop antennas are often used, which, despite their small dimensions, have good efficiency and allow operation in confined spaces.
Airborne and hidden antenna systems
The specifics of military equipment require the integration of antenna devices into the body contours, which gives rise to a class of on-board and hidden antennas. Built-in antennas are installed directly into the armor of tanks and armored personnel carriers, providing reliable contact and protection from bullets and shrapnel. The design of such systems often involves working with artificial soil, the role of which is played by the massive metal body of the machine.
For special forces and reconnaissance, hidden antennas are critical, which can be sewn into clothing, disguised as items of equipment, or in the form of a thin wire stretched indoors. Strap antennas or lanyard antennas for portable radios allow you to maintain communication while remaining undetected by enemy visual observation.
- 🚙 Onboard pin - reinforced base, vibration protection, work on the go.
- 🚙 Hidden wire — camouflage as equipment, minimal visibility.
- 🚙 Parasitic emitter — use of metal structures of the object (cables, handrails) as part of the antenna.
The efficiency of hidden antennas is usually lower than that of full-size antennas, so they require more sensitive radio receiving paths. An important aspect is the coordination with the radio frequency cable, the losses in which, with low efficiency of the emitter, become critical. Special matching transformers built into the base of the antenna are often used.
Antenna masts and lifting devices
Antenna height is a key factor in determining radio range, especially in rough terrain. Military communications complexes are equipped with telescopic masts, which can be sliding, inflatable or composite. Pneumatic masts convenient for quick deployment, but vulnerable to mechanical damage, while metal telescopic systems provide greater rigidity.
For portable complexes, lightweight composite masts made of fiberglass or carbon fiber are used, which do not conduct current and do not distort the directional pattern. The height of such masts is usually from 4 to 11 meters, which allows you to raise the antenna above the crowns of bushes. The antenna mount at the top of the mast must provide reliable electrical contact and protection from atmospheric static discharges.
| Mast type | Height (m) | Installation time (min) | Wind load |
|---|---|---|---|
| Telescopic | 6-12 | 5-10 | High |
| Pneumatic | 4-9 | 2-5 | Average |
| Composite (knee) | 10-20 | 15-30 | High |
| Inflatable (soft) | 5-8 | 3-7 | Low |
Installation of the mast requires compliance with grounding rules, especially in lightning-prone areas. Static electricity accumulating on a long antenna can damage the input stages of an expensive radio station. Therefore, the design must include arresters or grounding switches.
Coordination and configuration of the antenna path
Even the most advanced antenna will not work effectively without proper coordination with the feeder and transmitter. Standing Wave Ratio (SWR) is the main indicator of the quality of the tuning: a value above 2.0 is considered unacceptable for long-term operation, as it leads to overheating of the transmitter output stage. Tuning is done using antenna tuners or changing the geometric dimensions of the emitter.
☑️ Checking the antenna path
In field conditions, the technique of tuning to the minimum noise or to the maximum volume of the control station signal is often used. However, a professional approach requires the use of measuring instruments such as SWR meters or network analyzers. The length of the feeder (cable) also plays a role: with a strong mismatch, the length of the cable can affect the readings of the SWR meter, although this has less effect on the radiation efficiency.
⚠️ Attention: It is strictly forbidden to turn on the transmitter at full power without a connected antenna or with an SWR > 3.0, as this is guaranteed to burn out the output transistors of the radio station.
For broadband systems, active antennas with built-in amplifiers are used, which compensate for losses in short radiators. Such amplifiers are often powered through the feeder itself, which simplifies installation.
Specifics of operation in various conditions
The performance of military radio antennas varies dramatically depending on the time of day and season. On the HF bands, higher frequencies propagate better during the day, and lower frequencies at night, which requires restructuring or changing the antenna for optimal communication. In winter, snow cover can change the dielectric constant of the soil, affecting the operation of grounded antennas.
To improve communication in the forest, raise the antenna above the treetops. If this is not possible, use horizontal polarization, which has less attenuation through foliage than vertical polarization.
In mountainous areas, deep fading zones often occur due to multipath signal propagation. Using diversity reception with two antennas located several wavelengths apart can smooth out these dips. Also in the mountains, directional antennas are effective, oriented through passes, bypassing shielding ridges.
When working in urban areas or among rocks, complex interference patterns arise. Here it is preferable to use antennas with a circular radiation pattern or adapt the system to a specific direction to the base. Mobility and survivability of the antenna system remains the number one priority to ensure continuous command and control of troops.
How often should I check the SWR of antennas in the field?
It is recommended to check the SWR each time you deploy to a new position, as well as after strong winds, thunderstorms or mechanical impacts on the antenna. In inpatient settings, preventive examinations are carried out weekly.
Can civilian antennas be used for military radios?
Technically possible if the impedance (50 or 75 Ohms) and frequency range match. However, civilian antennas often lack EMP protection, lack mechanical strength, and may not meet stealth and camouflage requirements.
What to do if the antenna breaks in the field?
It is necessary to use an emergency supply of wire. A temporary dipole or slant beam can be made by calculating the approximate length using the formula 150/f. It is important to ensure insulation of mounting points and reliable grounding.
Does the paint on the antenna affect its performance?
Ordinary oil or acrylic paints have virtually no effect on the operation of antennas. However, metallic paints or coatings with a high graphite content may shield the signal and interfere with tuning and should not be used.
Which polarization is better for communication in the forest?
In a dense forest, horizontal polarization is attenuated less than vertical polarization. However, handheld radios with whip antennas use vertical polarization, so operators often have to look for clearings or hills.