Radio waves

Radio waves are widely used in radio communication, radio broadcasting, television, medicine, radiolocation, radio navigation, radio astronomy, nuclear physics, metallurgy industry (at welding, hardening, heat, weeding metal products, gluing plastic and wooden products, and so on).
Currently, adopted the following classification of radio frequencies (table. 1).

Table 1
Frequency High frequency (HF) Ultra-high frequency (UHF) Ultra high frequency (UHF)
  100 kHz - 30 MHz 30-300 MHz 300-300 000 MHz
Wavelengths Long Average Short Ultrashort Microwave
UHF centimeter mm
  3-1 km 1 km - 100 m 100-10 m 10-1 m 1 m-10 cm 10-1 cm 1 cm - 1 mm

Radio waves are used in medicine for therapeutic purposes in the form of sinusoidal modulated currents (5 kHz), therapy NATO national frequency (20 kHz), darsonvalization (110 kHz), diathermy (1,5 - 1,8 MHz), inductothermy (13.56MHz and 40,68 MHz), UHF-therapy (40,68 MHz), UHF therapy (460 MHz) and microwave therapy (2375 MHz) - see Darsonvalization, Diathermy, Pulse current, inductothermy, Microwave therapy, UHF-therapy.
Occupational hazards of radio waves. Artificial sources of electromagnetic fields of HF, UHF, SHF can be of different types of generators, inductors, blocks transmitters, feeder lines, capacitors, antenna systems and other Persons working with generators and the transmission system of electromagnetic waves of radio frequencies may be exposed to a variety of HF, UHF, SHF. When designing, testing, configuring, and operating plants, individual blocks that generate electromagnetic energy, perhaps, the radiation in the operating room. It is bad when the shielding blocks transmitters, waveguide channels, irrational location of antenna-feeder systems, etc., and also at infringement of safety. Sometimes it is possible irradiation of the personnel and population, which is not connected professionally with the radiating equipment, but fall under the influence of radio waves from the powerful antenna systems.
The intensity of the fields HF and UHF be estimated on the strength of the electric (E) and magnetic (And) components. For E intensity is expressed in volts per 1 meter (V/m)for I - amperes per 1 liter (a/m). In the microwave irradiation intensity is measured at the power flux density (MRP) and is expressed in watts per 1 cm2 (W/cm2), milliwatts (MW/cm2), microwatch (MCW/cm2).
Measurement of tension HF and UHF is a device IMP-1, in the range microwave flux density power - unit-1.
In order to prevent overexposure and health protection of workers in the USSR entered Sanitary standards and rules for working with sources of electromagnetic fields of high, ultra and ultra-high frequencies", which establishes maximum permissible levels (table. 2).

Table 2
Range Maximum permissible levels
E on N The power flux-density
Electrical component
100 kHz to 30 MHz (HF)
30-300 MHz (UHF)
On magnetic component
100 kHz to 1.5 MHz
On microwave
300-300 000 MHz
during the working day
within 2 hrs
for 15-20 minutes


for households and individuals not professionally connected with microwave irradiation

20 V/m
5/m

-


-
-
-



-

-
-

5 a/m


-
-
-



-

-
-

-


No more than 10 MW/cm2
Not more than 100 MW/cm2
Not more than 1000 MCW/cm2 with mandatory use of safety glasses

1 MCW/cm2

Systematic exposure to radio waves with levels above the acceptable, may lead to significant changes of some systems of the human body.
Notes the development of asthenic syndrome of various degrees of severity. Thus, the typical complaints of headaches, a loss of efficiency, sleep disturbances, irritability, increased sweating, the weakening of memory, sometimes decrease in sexual potency. Prolonged and frequent exposures exceed permissible levels can occur tremor century and fingers
the outstretched hands, increasing tendon reflexes, vegetative disorders (red persistent dermographism, acrocyanosis, rash and others), fear, hallucinations, fainting condition and other Results electroencephalogram indicate functional changes in the form of development of braking in the cortical cells.
From the side of cardiovascular system change often-type neurocirculatory dystonia with characteristic complaints: pain in the heart, shortness of breath, especially during exercise, feeling the heartbeat and "fading" of the heart. Objective: bradycardia, hypotension, muting the first heart sound, sometimes systolic murmur at the top, sinus arrhythmia, signs of myocardial hypoxia, and other rarely observed radiation, relative lymphocytosis, eosinophilia, increasing the number of red blood cells. However, changes of peripheral blood are not persistent, and sometimes by their performance contradictory.
There are tearing, pain in the eyes, feeling of "sand" for centuries conjunctivitis. For gross violations of safety when working with radiation sources, mainly microwave range can develop cataracts.
On the part of the endocrine system are marked strengthening the function of the pituitary and adrenal cortex, and the increased activity of the thyroid gland.
It must be borne in mind that the clinical picture when exposed to electromagnetic radiation of various ranges (HF, UHF, SHF) has its own characteristics and can greatly vary. All of these changes mostly reversible.
Prevention: the planning, siting, construction, acceptance and operation of all types of radio stations of the range to prevent overexposure people need to pay special attention to the shielding of the workplace or to provide remote control, rational accommodation blocks, two-way radio equipment, reducing time of stay of people in areas of likely exposure in accordance with the regulations, using if necessary personal protective equipment (overalls, goggles and other). Systematic measurement of the intensity of RF UHF and microwave fields.
When applying for a job are obligatory preliminary medical tests. Periodic medical examinations according to indications, but not less than 1 time a year. Persons with the presence of strong electromagnetic fields of radio frequencies, and General diseases, during which may worsen the conditions of chronic exposure to radio frequency, and women in the period of pregnancy and feeding are transferred to another job.
To work with the sources of electromagnetic fields only persons over 18 years of age. As medical means are used bracing, restorative and symptomatic drugs.