Encyclopedia of radio electronics and electrical engineering / Civil radio communications

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It is known that the electromagnetic field of artificial origin is a biologically active physical factor. It can have adverse effects on the human body and the environment. For this reason, it is necessary to carefully consider and solve the problems of "electromagnetic pollution" of the environment and ensure the protection of people from the possible harmful consequences of exposure to electromagnetic fields. By the way, the problems of electromagnetic ecology [1] can, in particular, arise during the operation of amateur radio stations in the KB range. And

The source of possible harmful effects can be both the transmitter of an operating radio station, irradiating the operator, and the exposure of the population to the radiation of the transmitting antenna. This article is devoted to the last problem. In general, to successfully solve the problem of "electromagnetic pollution" one must have:

• regulatory documents that determine the maximum permissible levels of exposure to electromagnetic fields;
• methodological documents that allow assessing the real levels of radiated electromagnetic fields (calculate and measure their parameters);
• systems of technical, organizational and biomedical measures aimed at preventing or minimizing the harmful effects of exposure.

The regulatory document that establishes the maximum permissible levels of exposure to electromagnetic fields are the sanitary rules and regulations "Electromagnetic radiation of the radio frequency range (EMR RF)" [2]. This document also determines that the placement and commissioning of transmitting radio engineering facilities designed to radiate electromagnetic energy into the surrounding space is allowed only with the permission of the relevant state sanitary and epidemiological center (TsGESN) in the republic, territory, region, cities of Moscow and Sankht-Petersburg. At the same time, only transmitting devices operating in the frequency band of 3 ... 30 MHz (amateur KB bands fall into it) with a power of up to 20 W and having antennas with a directivity of no more than 5 are not subject to agreement with the bodies of the State Sanitary and Epidemiological Supervision.

In accordance with the instructions of the Ministry of Communications "On the procedure for registration and operation of amateur transceiver radio stations for individual and collective use", a certain part of radio amateurs are allowed to use radio stations with a power of up to 200 W in the above frequency band without restriction on the value of the antenna directivity.

Thus, the owners of a part of amateur radio stations in Russia must obtain permission from the Central State Sanitary and Epidemiological Commission to operate on the air. This is done through the development of a sanitary passport of the transmitting radio engineering facility (PRTO) and its approval by the Central State Sanitary and Epidemiological Service. The development of such a passport in the full scope of the requirements [2] for radio amateurs, of course, presents certain difficulties.

Of course, sanitary standards are not directed against radio amateurs. Their implementation is aimed at controlling EMP sources. At the same time, it is simply impossible to turn a blind eye to the existence of amateur radio stations in the KB range as sources of EMP from the standpoint of ensuring human electromagnetic safety. The right of Russian citizens to maintain health is enshrined in the Laws of the Russian Federation "On the sanitary and epidemiological well-being of the population", "On environmental protection", which require the implementation of the current Federal sanitary norms and rules, including RF EMR.

In order to link the requirements of [2] and the above Instructions for solving the problems faced by radio amateurs related to coordinating the placement of radio stations with the centers of the GSEN, the lead institute for electromagnetic safety problems, the Samara Branch Research Institute of Radio (SONIIR), was tasked by the Ministry of Communications of the Russian Federation by assessing the levels of electromagnetic fields (EMF) near HF amateur radio stations.

It should be noted that the structure of the electromagnetic field in the vicinity of HF antennas is extremely complex and depends on many factors: the type of antennas, operating frequencies, the level of radiated power, the polarization of the radiated field, the electrical parameters of the underlying surface, the nature and degree of building, the mutual influence of antennas. A feature of electromagnetic prediction (calculation of EMF levels) in the KB range is that the field must be determined at distances commensurate with the geometric dimensions of the antennas and the wavelength. At the same time, it is clear that it makes no sense to talk about the value of the antenna directivity coefficient. The boundaries of sanitary zones can fall both in the near and intermediate zones of the antennas, and in the far zone. In addition, in the KB range, the characteristics of the radiation and the structure of the fields near the antennas largely depend on the electrical properties of the underlying surface. Antennas that create fields of predominantly one polarization (horizontal or vertical) in the wave zone, create fields of other polarizations in the near zone, and their levels are comparable, and sometimes exceed the levels of the main polarization.

Theoretical studies have shown that due to the complex dependence of the field on certain parameters, it is impossible to obtain simple relationships or universal curves. For the practical implementation of electromagnetic forecasting, it is necessary to know the real behavior of each polarization component at various distances and observation heights, which can only be described within the framework of rigorous solutions.

In accordance with the foregoing, SONIR developed a method for predicting EMF levels near the antennas of amateur HF radio stations, based on rigorous solutions of the corresponding electrodynamic problems of thin-wire structures with known distribution functions of currents over radiators, which are determined on the basis of numerical solutions of integral equations.

The field of complex antennas is determined by integrating the fields of the corresponding elementary electric vibrators over the linear dimensions of these antennas. In this case, a number of specific problems of antenna theory are solved, which allow more accurate calculation of near fields (taking into account the mutual influence of antenna elements and real distributions of currents over radiators).

Based on the developed software for calculating the EMF of amateur radio stations in the KB band, an assessment of the field strength levels (calculations) was carried out for four amateur bands - 10, 15, 20 and 40 meters, as well as for the CB band (27 MHz) for dry soil: ε=3; σ=0.001 S/m (worst case underlying surface).

Calculations were carried out for common types of amateur radio antennas with a transmitter power of 200 W: Windom, W3DZZ, Zeppelin, Ground plane, half-wave horizontal vibrator (HVD), "long horizontal wire" [3]. When calculating the EMF of Windom, Ground Plane, and PHD antennas, the antenna dimensions were chosen in accordance with [3] for each of the above wavelength subbands (for PHD, the arm length is λ/4). For the Zeppelin antenna, the length of the antenna is 21,5 m, which is λ/2 for the range of 40 meters. In the ranges of 20, 15 and 10 meters, the antenna works like a long wire with a length that is a multiple of λ/2. The "Long Wire" antenna is a 50 m long wire for 10, 15, 20 meters and 100 m for 40 meters.

The results of calculations of the field strength levels show that for almost all types of antennas, the maximum permissible level (MPL) of the KB range of 10 V/m is exceeded [2]. The excess of the remote control is observed at distances up to 10 m from the antenna power connection point at a height between the plane of the antenna and the plane of the observation point of 4 meters, with the exception of the Long Wire antenna, where the remote control is exceeded along the wire along its entire length.

Based on the results of calculations of the field strength levels, in accordance with [2], diagrams of sanitary zones at the height of the antenna suspension were constructed (Fig. 1 - 6). In the figures, the radius indicates the distance in meters. For antennas of horizontal polarization, depicted in the plane of the limitation zones in the form of thick straight lines, an azimuthal dependence of the boundaries of the zones is visible, which in the general case repeats the pattern of current distribution over the antennas (Fig. 1, 2, Fig. 4-6). For a vertically polarized antenna ("Ground Plane"), no azimuthal dependence is observed - the zone is a circle (Fig. 3). It can be seen from the figures that the boundaries of the development restriction zones at the height of the antenna suspension do not extend more than 10 meters from any point of the antenna.

(click to enlarge)

To normalize the electromagnetic environment, it is necessary to present a number of requirements for antennas of amateur radio stations in the KB range (mainly in terms of their placement).

The analysis of the results of the assessment of the electromagnetic environment at the locations of antennas of amateur radio stations operating in the frequency band of 3 ... KB stations", which sets out the requirements for the placement of antennas.

Temporary guidelines were approved by the Deputy Chief State Sanitary Doctor of the Russian Federation and sent to the TsGSN.

The following are excerpts from these recommendations of interest to radio amateurs.

It should be specially emphasized that in case of non-compliance with the recommendations on the placement of antennas (for example, when installing antennas between houses), the owner of the radio station is obliged to develop and agree on the sanitary passport of the radio station in full compliance with the requirements of the mentioned sanitary norms and rules.

The authors of the article hope that the information provided will be useful to the numerous galaxy of shortwavers, to which they respect, in the preparation and coordination of sanitary passports of the amateur shortwave radio station with the bodies of the State Sanitary and Epidemiological Supervision. The authors also believe that the high intellectual level and civic consciousness of the short-wavers will allow them to correctly carry out this procedure and will not allow a negative reaction to the bodies of the State Sanitary and Epidemiological Supervision, since the Russian people are building a democratic legal state in which the rights and obligations of all citizens without exception must be respected.

Literature

1. Buzov A. Ya., Romanov V. A. The problem of electromagnetic ecology. Aspects of metrological support. Peculiarities of rationing, forecasting and measurements of electromagnetic fields near technical facilities and telecommunication objects. - Metrology and measuring technique 8 communications. 1999. No. 5.
2. Electromagnetic radiation of the radio frequency range (EMR RF). Sanitary rules and regulations. SanPiN - 2.2.4/2.1.8.055-96. - M.; Goskomsanepidnadzor of Russia. 1996.
3. Rothammel K. Antennas. - M.; Energy, 1979. p. 320.

Excerpts from Temporary guidelines for the organization of control of amateur radio stations

1. Radio amateur radio stations operating in the shortwave frequency range (3-30 MHz) and radio stations operating in the "civilian" frequency range (26,5-27.5 MHz) (RRS and RGD) are objects of state sanitary and epidemiological supervision in accordance with requirements of sanitary rules and norms "Electromagnetic radiation of the radio frequency range (EMR RF)" SanPiN 2 2.4 / 2.1.8.055-96.

2. Under the supervision of the State Sanitary and Epidemiological Service, RRS and RGD should be taken, having a maximum power supplied to the antenna that exceeds the values ​​\u6.2b\u2.2.4bspecified in clause 2.1.8.055. SanPiN 96/20-5 (power over XNUMX W with antenna directivity over XNUMX).

3. When coordinating the placement of RRS and RGD, owned by individuals and having a power of 20-200 W supplied to the antenna, it must be ensured that people do not have access to the antenna installation area at a distance of at least 10 m from any of its points. When installed on the roof of a building, the antenna must be mounted at a height of at least 1,5 m above the roof, while ensuring a distance from any point of it to neighboring buildings of at least 10 m for any type of antenna and any direction of its radiation. In this case, the calculation of the sanitary protection zone and the development restriction zone is not required.

4. The control of the electric field strength during the commissioning of the RRS and RGD and subsequent supervision of its operation can be carried out at the discretion of the specialists of the center of the State Sanitary and Epidemiological Supervision.

5. In exceptional cases, when the placement of the antenna in compliance with the above requirements is impossible, when deciding on the coordination of the placement of the RRS and RGD, instrumental control of the intensity (according to the electrical component according to SanPiN 2.2.4 / 2.1.8.055-96) of electromagnetic radiation of the radio frequency range (EMR RF) when the radio transmitter is in operation is mandatory.

6. In this case, the sanitary passport of the transmitting radio engineering facility (PRTO) does not need to include antenna radiation patterns and materials for calculating the distribution of RF EMP intensity in the adjacent territory, as well as the results of measuring the intensity of RF EMP, if they were not made.

7. When agreeing on the placement of RRS and RGD belonging to legal entities, control measurements of the intensity of electromagnetic radiation in the radio frequency range are mandatory and the measurement protocol is attached to the sanitary passport of the PRTO.

V. When coordinating the placement of a collective RRS and RGD with a power supplied to the antenna of 200-1000 W, it must be ensured that there is no access for people and the absence of neighboring buildings at a distance of at least 25 m from any point of the antenna for any type of antenna and any direction of its radiation. When installed on the roof of a building, the antenna must be mounted at a height of at least 5 m above the roof, while ensuring a distance from neighboring buildings of at least 25 m. In this case, calculations of the sanitary protection zone and the development restriction zone are not required. Instrumental control of the intensity of RF EMR during the operation of the radio transmitter is mandatory. In this case, the PRTO sanitary passport does not need to include antenna patterns and materials for calculating the distribution of the intensity of electromagnetic radiation in the radio frequency range (EMR RF) in the adjacent territory.

9. The organization of control of the field strength levels is assigned to the owner of the PRTO.

10. When a radio transmitter is independently manufactured, its technical parameters entered in the sanitary passport must be confirmed by the bodies of the Glavgosvyaznadzor of Russia or other authorized bodies.

11. When staying in the area of ​​​​location of the RRS and RGD antennas of persons. not professionally involved in exposure to RF EMI, the transmitter must be turned off.

12. These temporary guidelines supplement the requirements of clause 6.2 of SanPiN 2.2.4 / 2.1.8.055-96 in terms of amateur shortwave radio stations in the 3-30 MHz range and radio stations operating in the "civilian" frequency range (26,5-27,5, 2.2.4 MHz), and are valid until the relevant changes are made to SanPiN 2.1.8.055 / 96-XNUMX when they are adjusted.

Authors: A.Buzov, Yu.Kolchugin, S.Mishenkov, V.Romanov

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