In this article, we will review the capabilities of the Rufus program for creating ...
I was very surprised when my simple homemade detector-indicator went off scale next to a working microwave oven in our work canteen. It's all shielded, maybe some kind of malfunction? I decided to check my new oven, it was practically not used. The indicator also deviated to the full scale!
I assemble such a simple indicator in a short time every time I go to field tests of receiving and transmitting equipment. It helps a lot in work, you don’t have to carry a lot of devices with you, it’s always easy to check the transmitter’s performance with a simple homemade product (where the antenna connector is not completely turned on, or you forgot to turn on the power). Customers like this style of retro indicator very much, they have to leave it as a gift.
The advantage is the simplicity of design and lack of power. Eternal device.
It is easy to do, much simpler than exactly the same "Detector from a network extension cord and a bowl for jam" in the medium wave range. Instead of a network extension cord (inductor) - a piece of copper wire, by analogy, you can have several wires in parallel, it will not be worse. The wire itself in the form of a circle 17 cm long, at least 0.5 mm thick (for greater flexibility I use three such wires) is both an oscillatory circuit at the bottom and a loop antenna of the upper part of the range, which ranges from 900 to 2450 MHz (I did not check the performance above ). It is possible to apply a more complex directional antenna and input matching, but such a digression would not be consistent with the title of the topic. A variable, building or just a capacitor (aka a basin) is not needed, on the microwave - two connections are nearby, already a capacitor.
There is no need to look for a germanium diode, it will be replaced by a HSMP PIN diode: 3880, 3802, 3810, 3812, etc., or HSHS 2812, (I used it). If you want to go above the microwave oven frequency (2450 MHz), choose diodes with a lower capacitance (0.2 pF), HSMP -3860 - 3864 diodes may work. Do not overheat during installation. It is necessary to solder point-quickly, in 1 second.
Instead of high-impedance headphones, there is an arrow indicator. The magnetoelectric system has the advantage of inertia. The filter capacitor (0.1 uF) helps the needle move smoothly. The higher the resistance of the indicator, the more sensitive the field meter (the resistance of my indicators is from 0.5 to 1.75 kOhm). The information embedded in a deviating or twitching arrow acts magically on those present.
Such an indicator of the field, installed next to the head of a person talking on a mobile phone, will first cause amazement on the face, perhaps bring the person back to reality, and save him from possible diseases.
If you still have strength and health, be sure to click on one of these articles.
Instead of a pointer device, you can use a tester that will measure the DC voltage at the most sensitive limit.
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| Microwave indicator circuit with LED. |
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| Microwave indicator with LED. |
Tried LED as indicator. This design can be made in the form of a keychain using a flat 3-volt battery, or inserted into an empty mobile phone case. The standby current of the device is 0.25 mA, the operating current directly depends on the brightness of the LED and will be about 5 mA. The voltage rectified by the diode is amplified by the operational amplifier, accumulated on the capacitor and opens the switching device on the transistor, which turns on the LED.
If the pointer indicator without a battery deviated within a radius of 0.5 - 1 meter, then the color music on the diode moved away up to 5 meters, both from a cell phone and from a microwave oven. As for the color music, I was not mistaken, see for yourself that the maximum power will be only when talking on a mobile phone and with extraneous loud noise.
Adjustment.
I collected several of these indicators, and they started working right away. But still there are nuances. In the on state, at all pins of the microcircuit, except for the fifth one, the voltage should be equal to 0. If this condition is not met, connect the first pin of the microcircuit through a 39 kΩ resistor to minus (ground). It happens that the configuration of the microwave diodes in the assembly does not match the drawing, so you need to adhere to the electrical diagram, and before installing, I would advise you to ring the diodes for their compliance.
For ease of use, you can degrade the sensitivity by reducing the 1mΩ resistor, or reduce the length of the wire turn. With the above ratings, the microwave fields of base telephone stations feel within a radius of 50 - 100 m.
With this indicator, you can draw up an ecological map of your area and highlight places where you can’t hang out with strollers or sit up with children for a long time.
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Be under the base station antennas |
Analog level indicator.
I decided to try to complicate the microwave indicator a little, for which I added an analog level meter to it. For convenience, I used the same element base. The diagram shows three DC operational amplifiers with different gains. In the layout, I settled on 3 cascades, although you can also plan for the 4th using the LMV 824 chip (4th op amp in one package). Using power from 3, (3.7 telephone battery) and 4.5 volts, I came to the conclusion that it is possible to do without a key cascade on a transistor. Thus, we got one microcircuit, a microwave diode and 4 LEDs. Considering the conditions of strong electromagnetic fields in which the indicator will work, I used blocking and filtering capacitors for all inputs, for feedback circuits and for powering the op-amp.
Adjustment.
In the on state, at all pins of the microcircuit, except for the fifth one, the voltage should be equal to 0. If this condition is not met, connect the first pin of the microcircuit through a 39 kΩ resistor to minus (ground). It happens that the configuration of the microwave diodes in the assembly does not match the drawing, so you need to adhere to the electrical diagram, and before installing, I would advise you to ring the diodes for their compliance.
This design has already been tested.
The interval from 3 LEDs on to completely extinguished is about 20 dB.
Power supply from 3 to 4.5 volts. Standby current from 0.65 to 0.75 mA. The operating current when the 1st LED lights up is from 3 to 5 mA.
This microwave field indicator on a microcircuit with the 4th op-amp was assembled by Nikolai.
Here is his diagram.
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| Dimensions and marking of pins of the LMV824 chip. |
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| Mounting the microwave indicator on the LMV824 chip. |
Similar in parameters chip MC 33174D, which includes four operational amplifiers, made in a dip package, is larger, and therefore more convenient for amateur radio installation. The electrical configuration of the pins completely coincides with the L MV 824 microcircuit. On the MC 33174D microcircuit, I made a prototype of a microwave indicator for four LEDs. A 9.1 kΩ resistor is added between pins 6 and 7 of the microcircuit and a 0.1 uF capacitor is parallel to it. The seventh output of the microcircuit, through a 680 Ohm resistor, is connected to the 4th LED. Part size 06 03. Power supply of the layout from a lithium cell 3.3 - 4.2 volts.
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| Indicator on the MC33174 chip. |
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| Reverse side. |
The original design of the economical field indicator has a souvenir made in China. This inexpensive toy has: a radio, a clock with a date, a thermometer and, finally, a field indicator. A frameless, flooded microcircuit consumes negligibly little energy, since it works in a timing mode, it reacts to the inclusion of a mobile phone from a distance of 1 meter, simulating a few seconds with LED indication of an alarm with headlights. Such circuits are implemented on programmable microprocessors with a minimum number of parts.
Addition to comments.
Selective field meters for the amateur band 430 - 440 MHz
and for the PMR band (446 MHz).
Microwave field indicators for amateur bands from 430 to 446 MHz can be made selective by adding an additional circuit L to Sk, where L to is a coil of wire with a diameter of 0.5 mm and a length of 3 cm, and Sk is a tuning capacitor with a nominal value of 2 - 6 pF . The coil of wire itself, as an option, can be made in the form of a 3-turn coil, with a pitch wound on a mandrel with a diameter of 2 mm with the same wire. It is necessary to connect the antenna to the circuit in the form of a piece of wire 17 cm long through a 3.3 pF coupling capacitor.
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| Range 430 - 446 MHz. Instead of a coil, a coil with a step winding. |
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| Scheme for ranges 430 - 446 MHz. |
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| Mounting on the frequency range 430 - 446 MHz. |
By the way, if you are seriously engaged in microwave measurement of individual frequencies, then you can use SAW selective filters instead of a circuit. In the metropolitan radio stores, their range is currently more than sufficient. It will be necessary to add an RF transformer to the circuit after the filter.
But that's another topic that doesn't fit the title of the post.
Are you tired of the neighbors' too loud music or just want to make some interesting electrical device yourself? Then you can try to build a simple and compact electromagnetic pulse generator that can disable electronic devices nearby.
An EMP generator is a device capable of generating a short-term electromagnetic disturbance that radiates outward from its epicenter, disrupting the operation of electronic devices. Some bursts of EMP occur naturally, such as in the form of an electrostatic discharge. There are also artificial EMP bursts, such as a nuclear electromagnetic pulse.
This tutorial will show you how to assemble an elementary EMP generator using commonly available items: a soldering iron, solder, a disposable camera, a push button switch, insulated thick copper cable, enameled wire, and a high current lockable switch. The presented generator will not be too strong in power, so it may not be able to disable serious equipment, but it can affect simple electrical appliances, so this project should be considered as a training project for beginners in electrical engineering.
So, first, you need to take a disposable camera, for example, Kodak. Next, you need to open it. Open the case and find a large electrolytic capacitor. Do this with rubber dielectric gloves so as not to get an electric shock when the capacitor is discharged. When fully charged, it can be up to 330 V. Check the voltage on it with a voltmeter. If there is still a charge, then remove it by closing the capacitor leads with a screwdriver. Be careful, when closing, a flash will appear with a characteristic pop. After discharging the capacitor, pull out the circuit board on which it is installed and find the small on/off button. Unsolder it, and solder your switch button in its place.
Solder two insulated copper cables to the two pins of the capacitor. Connect one end of this cable to a high current switch. Leave the other end free for now.
Now you need to wind the load coil. Wrap the enameled wire 7 to 15 times around a 5 cm round object. Once the coil is formed, wrap it with duct tape for added security while using it, but leave two wires protruding to connect to the terminals. Use sandpaper or a sharp blade to remove the enamel coating from the ends of the wire. Connect one end to the capacitor terminal and the other end to a high current switch.
Now we can say that the simplest electromagnetic pulse generator is ready. To charge it, simply connect the battery to the appropriate pins on the PCB with the capacitor. Bring a portable electronic device that you don't mind near the coil and press the switch.
Remember not to hold down the charge button while generating EMP, otherwise you may damage the circuit.
A selection of schemes and designs of homemade bug detectors to search for radio bugs. Usually, radio eavesdropping circuits of radio bookmarks operate at a frequency in the range of 30 ... 500 MHz and have a very low transmitter power of about 5 mW. Sometimes, the bug works in standby mode and is activated only when there is noise in the monitored room.
This article discusses a bug detector scheme for finding eavesdropping devices. The bug detector circuit is usually a high frequency voltage bridge detector operating over a huge frequency range.
Bug detector. A simple voltage detector circuit |
This simple circuit catches radio bugs perfectly, but only in the frequency range up to 500 MHz, which is a significant disadvantage. The intensity detector antenna is made of a half-meter long pin with a diameter of not more than 5 mm and is insulated from the outside. Further, the signal is detected by a germanium diode VD1, and amplified by transistors VT1, VT2). The amplified UPT signal passes to the threshold device (DD1.1) and the sound generator made on the elements DD1.2 - DD1.4, which is loaded on the piezo emitter. As inductance L1, a low-frequency choke on a 2000NM ferrite ring is used, containing 200 turns of PEL 0.1 wire.
Another simple homemade device for searching for radio bookmarks is shown in the diagram in the figure just above. This is a broadband high-frequency voltage bridge detector operating in the range from 1...200 MHz and makes it possible to find "bugs" at a distance of 0.5 to 1 m.
To increase the sensitivity, a proven method of measuring small alternating voltages using a balanced diode-resistive bridge is used.
Diodes VD5, VD6 are designed to provide thermal stabilization of the circuit. Three-level comparators made on the elements D1.2 ... D1.4 and LEDs are connected to their outputs, which are used as an indicator. As a voltage regulator of 1.4 volts, diodes VD1, VD2 are used. Working with the device is not very easy and practical skills are required, since the circuit can react to some household appliances, televisions and computers.
In order to simplify the process of detecting radio bookmarks, you can use interchangeable antennas of different lengths, from which the sensitivity of the circuit will change
When you turn on the device for the first time, you need to use the resistor R2 to make the HL3 LED glow. This will be the initial sensitivity level relative to the background. Then, if we bring the antenna closer to the radio signal source, other LEDs should also light up, depending on the level of the radio signal amplitude.
Resistor R9 adjust the threshold sensitivity level of the comparators. The circuit is powered by a nine-volt battery until it is discharged to 6 volts.
Resistors R2 can be taken SPZ-36 or other multi-turn, R9 SPZ-19a, the rest are any; capacitors C1...C4 K10-17;.
LEDs can also be used any, but with low current consumption. The design of the circuit is only up to your imagination.
During operation, any radio bug emits radio waves, which are fixed by the detector antenna and enter the base of the first transistor through a high-frequency filter, which is made on capacitors C1, C2 and resistance R1.
The filtered signal is amplified by the bipolar transistor VT1 and goes through the capacitance C5 to the high-frequency first diode. Variable resistance R11 regulates the share of the signal on the diode coming to the operational amplifier DD1.3. It has a high gain which is set by C9, R13, R17.
If the signal from the radio bookmarks is not on the antenna, then the signal level at the first output of the OS DD1.3 tends to zero. When radio emission occurs, the amplified signal from this output will go to a voltage-controlled audio frequency generator assembled on elements DD1.2., DD1.4 of the MC3403P chip and the third transistor. From the output of the generator, the pulses are amplified by the second transistor and fed to the speaker.
Bug detector with 10 LEDs |
The basis of the electromagnetic field detector is the LM3914 chip, which has ten comparators in its internal composition and, accordingly, the same number of outputs for connecting LEDs. One of the outputs of each comparator is connected to the input through a signal amplifier, the other output is connected to a resistive divider at the point corresponding to the specified indication level.
The beginning and end of the resistive divider are connected to pins 4 and 6. The fourth is connected to the negative pole of the source in order to provide a voltage indication from zero. The sixth is connected to the 1.25 volt reference output. This connection indicates that the first LED will light at a voltage level of 1.25 volts. Thus, the step between the LEDs will be equal to 0.125.
The circuit operates in the “Point” mode, that is, a certain voltage level corresponds to the glow of one LED. If this contact is connected to the plus of the power source, then the indication will be carried out in the "Column" mode, the LED of the set level will light up and lower. By changing the value of R1, you can adjust the sensitivity of the detector. As an antenna, you can take a piece of copper wire.
Almost every novice radio amateur tried to assemble a radio bug. There are quite a few circuits on our site, many of which contain only one transistor, a coil and a strapping - several resistors and capacitors. But even such a simple circuit will not be easy to properly configure without special instruments. We will not talk about the wavemeter and the RF frequency counter - as a rule, novice radio amateurs have not yet acquired such complex and expensive devices, but it is not just necessary to assemble a simple RF detector, but it is a must.
Below are the details for it.
This detector allows you to determine whether there is a high frequency radiation, that is, whether the transmitter generates at least some kind of signal. Of course, it will not show the frequency, but for this you can use a regular FM radio.
The design of the RF detector can be any: surface mounting or a small plastic box where the dial indicator and other parts will fit, and we will bring the antenna (a piece of thick wire 5-10 cm) out. Capacitors can be used of any type, deviations in the ratings of parts within a very wide range are permissible.
RF Detector Details:
- Resistor 1-5 kiloohm;
- Capacitor 0.01-0.1 microfarads;
- Capacitor 30-100 picofarads;
- Diode D9, KD503 or GD504.
- Pointer microammeter for 50-100 microamperes.
The indicator itself can be anything, even if it is for a large current or voltage (voltmeter), just open the case and remove the shunt inside the device, turning it into a microammeter.
If you do not know the characteristics of the indicator, then in order to find out what current it is, simply connect it to an ohmmeter first to a known current (where the marking is indicated) and remember the percentage of scale deviation.
And then connect an unknown pointer device and by the deviation of the arrow it will become clear what current it is designed for. If the indicator at 50 µA gave a full deviation, and an unknown device at the same voltage - half, then it is 100 µA.
For clarity, I assembled an RF signal detector with a hinged mount and measured the radiation from a freshly assembled FM radio microphone.
When the transmitter circuit is powered from 2V (strongly shrunken crown), the detector needle deviates by 10% of the scale. And with a fresh 9V battery - almost half.
CONTENT:
In recent years (even, perhaps, already a dozen or two years), microwave radiation has become relevant. More precisely, this is electromagnetic radiation of ultrahigh frequencies (frequency, approximately, from 300 ... 400 MHz to 300 GHz, wavelength from 1 mm to 0.5 ... 1 m). There is currently a heated debate in the media about whether this radiation is harmful or not, whether it should be feared, whether it has a harmful effect or can be neglected.
We will not go deep here and engage in evidence or refutation, because the facts of the negative impact of this radiation are well known, proven by medical scientists (for example, Soviet scientists) back in the last century - the 60s. Numerous experiments were carried out on mice, rats (we don’t remember what about other animals). They were irradiated with centimeter, decimeter and other waves of various intensities ... On the basis of these studies, Soviet GOSTs for microwave radiation were born, which, by the way, were the most stringent in the world. It was precisely because of the harmfulness of microwave radiation identified by physicians that microwave ovens (for mass use) were banned in the USSR; and not due to, allegedly, the lack of the ability to arrange their large-scale production.
There are science articles, monographs. Anyone who wants to can see them on their own. Even in Ufa they can be found in the library named after N.K. Krupskaya (now it is called the library named after Zaki-Validi); well, in Moscow and other similar cities, I think, all the more problems with this. For those who have a desire, it is probably not difficult to spend a couple of days and read books with a title like “The Effect of EMP on Living Organisms”. How these same living organisms first blushed, then feverishly rushed through the cells, and then died as a result of exposure to high doses of microwaves. How long-term doses of even seemingly small levels of microwave radiation (below the thermal threshold) led to changes in metabolism (rats, mice), partly to infertility, etc. Therefore, disputes here, apparently, are inappropriate. Unless, of course, one does not pretend that these studies are “wrong”, “no one knows for sure whether it is harmful or not”, etc. - only such, if I may say so, "arguments" are usually available to those who wish to dispute this.
Then the market began in the USSR (that is, in the CIS). Along with the development of mobile communications. In order to somehow justify the presence of cell towers (and Internet providers), the state had to reduce the severity of GOSTs. As a result, the maximum allowable doses of radiation prescribed in GOSTs have increased. Once every 10. The level that was previously considered acceptable for employees of airfields, radar stations (such workers used to receive additional payments for harmfulness and were given a number of benefits) is now considered acceptable for the entire population.
Effect of microwave radiation on living organisms
So, what does science say about the effect of microwave radiation on the body? Let's take a look at some of the results. scientific studies conducted in the 60s-70s of the last century. Scroll scientific papers We will not cite publications here, but will confine ourselves to a brief review of some of them. As you can see, a considerable amount has been defended on this topic. dissertations, both candidate and doctoral, but most of them scientific results is probably unknown to the general public for obvious reasons. Scientists have proven that long-term systematic exposure of the body to electromagnetic fields, especially in the microwave (3×10 9 ... 3×10 10 Hz) and UHF (3×10 8 ... 3×10 9 Hz) ranges, at intensities above the maximum allowable, can lead to to some functional changes in it, primarily in the nervous system. Note: in those years, the following maximum permissible levels of exposure to microwave and UHF energy were established:
when irradiated throughout the working day - 10 μW / cm 2 (0.01 mW / cm 2)
when irradiated up to 2 hours per working day - 100 μW / cm 2 (0.1 mW / cm 2)
when irradiated for 15-20 min. For a working day - 1000 μW / cm 2 (1 mW / cm 2) with the obligatory use of goggles; during the rest of the day by more than 10 μW/cm 2 .
These changes, first of all, are manifested in headache, sleep disturbance, increased fatigue, irritability, etc. Microwave fields with intensities well below the thermal threshold can cause nervous system exhaustion. Functional changes caused by the biological effects of electromagnetic fields in the body can accumulate (accumulate), but are reversible if radiation is excluded or working conditions are improved.
Morphological changes are especially noted that can occur in the eyes and lead in severe cases to cataracts (clouding of the lens). These changes were found when exposed to radiation with different wavelengths - from 3 cm to 20 m. Changes occurred both during short-term exposure with a high thermogenic intensity (hundreds of mW/cm mW / cm 2, i.e. below the thermal threshold. Pulsed radiation (high intensity) is more dangerous to the eyes than continuous.
Morphological changes in the blood are expressed in changes in its composition and indicate the greatest impact of centimeter and decimeter waves (that is, the very waves that are used in cellular communications, microwave ovens, Wi-Fi, etc.).
Another type of change caused by exposure to electromagnetic fields are changes in the regulatory function of the nervous system, which is expressed in violation of:
A) Previously developed conditioned reflexes
B) The nature and intensity of physiological and biochemical processes in the body
C) Functions of various parts of the nervous system
D) Nervous regulation of the cardiovascular system
Table 1
Disorders of the function of the cardiovascular system in people exposed to systematic exposure to electromagnetic fields of different frequencies
| Field options | Percentage of cases with this disorder in the group of people studied | |||
| Frequency range | Intensity | Arterial hypotension | Bradycardia | Slow intraventricular conduction |
| Microwave (centimeter waves) (3×10 9 …3×10 10 Hz) | <1 мВт/см 2 | 28 | 48 | 25 |
| VHF (3×10 7 …3×10 8 Hz) | Below thermal threshold | 17 | 24 | 42 |
| RF (3×10 6 …3×10 7 Hz) | Tens-hundreds V/m | 3 | 36 | - |
| MF (3×10 5 …3×10 6 Hz) | Hundreds to 1000 V/m | 17 | 17 | - |
| In the absence of fields | 14 | 3 | 2 | |
Changes in the cardiovascular system are expressed in the form of hypotension, bradycardia and slowing of intragastric conduction mentioned above, as well as changes in blood composition, changes in the liver and spleen, all of which are more pronounced at higher frequencies. Table 2 presents the main types of disorders occurring under the influence of microwave radiation in a living organism.
table 2
The nature of changes in living organisms observed in chronic experiments on animals (A.N. Berezinskaya, Z.V. Gordon, I.N. Zenina, I.A. Kitsovskaya, E.A. Lobanova, S.V. Nikogosyan, M .S. Tolgskaya, P.P. Fukalova)
| Researched Features | The nature of the changes |
| Histamine | Increase in blood levels, undulating nature of changes |
| Vascular tone | Hypotensive effect |
| peripheral blood | Tendency to leukopenia, change in white sprout (decrease in segmented neutrophils) |
| Sexual function, ovarian function | Violation of the course of the estrous cycle |
| Fertility | Decrease in irradiated females, tendency to overmaturity, stillbirth |
| Offspring | Developmental delay, high postnatal death |
| Eyes | Retinal angiopathy, cataract |
The biological action of different ranges of radio frequencies in the general case has the same direction. However, there are some features of biological effects for individual wavelengths.
Table 3
| Wave range | Irradiation intensity | Animal death time in minutes and % | |
| 50% | 100% | ||
| Medium (500 kHz) | 8000 V/m | Not | |
| Short | 5000 V/m | 100 | |
| 14.88 MHz | 9000 V/m | 10 | |
| Ultrashort | 5000 V/m | ||
| 69.7 MHz | 2000 V/m | 1000-120 | 130-200 |
| 155 | 700 V/m | 100-120 | 130-200 |
| 191 | 350 V/m | 100-150 | 160-200 |
| Microwave | |||
| decimeter | 100 mW / cm 2 | 60 | |
| centimeter | |||
| 10 cm | 100 mW / cm 2 | 15 | 60 |
| 3 cm | 100 mW / cm 2 | 110 | |
| Millimeter | 100 mW / cm 2 | 180 | |
Table 4
Survival rate of animals exposed to different wavelengths
| Wave range | Duration of exposure that does not cause death of animals | ||
| 100 mW / cm 2 | 40 mW / cm 2 | 10 mW / cm 2 | |
| decimeter | 30 minutes | >120 min | > 5 hours |
| 10 cm | 5 minutes | 30 minutes | > 5 hours |
| 3 cm | 80 min | >180 min | > 5 hours |
| Millimeter | 120 min | >180 min | > 5 hours |
Note: 1 mW / cm 2 \u003d 1000 μW / cm 2
Table 5
Animal lifespan
| Irradiation intensity, mW / cm 2 | Minimum lethal exposure, min | Dose, mW / cm 2 / h |
| 150 | 35 | 87 |
| 97 | 45 | 73 |
| 78 | 56 | 73 |
| 57 | 80 | 76 |
| 45 | 91 | 68 |
Scientific research were carried out by scientists on 493 adult male animals: 213 white rats weighing 150-160 g and 280 white mice weighing 18-22 g, which in different groups were exposed to 3-, 10-cm and decimeter waves with an intensity of 10 mW / cm 2. Animals were exposed to daily irradiation for 6...8 months. The duration of each irradiation session was 60 min. Table 6 provides data on the weight gain of irradiated and control animals.
Under the influence of irradiation, certain histological changes occur in the organs and tissues of animals. Histological studies show degenerative changes in parenchymal organs and the nervous system, which are always combined with proliferative changes. At the same time, animals almost always remain relatively healthy, giving certain indicators of weight gain.
Interestingly, low doses of radiation (5-15 min) are stimulating in nature: they cause a slightly greater weight gain in the animals of the experimental group compared to the control group. Apparently, this is the influence of the compensatory reaction of the body. Here, in our opinion, we can draw a (very rough) analogy with swimming in ice water: if you swim in ice water sometimes for a short time, then this can contribute to the healing of the body; while PERMANENT stay in it, of course, will lead to its death (unless it is the body of a seal, walrus, etc.). True, there is one BUT. The fact is that after all, water is a natural, NATURAL environment for living organisms, in particular, for humans (like air, for example). Whereas microwave waves are practically absent in nature (if we do not take into account any distant, with the exception of the sun (the level of microwave radiation from which is very, very low), located in other galaxies, various kinds of quasars and some other space objects that are sources Microwave Of course, many living organisms also emit microwaves to some extent, but the intensity is so low (less than 10 -12 W / cm 2) that it can be considered absent.
Table 6
Change in the weight of animals under the influence of microwave radiation
| Waveband (animal) | Irradiation intensity, mW / cm 2 | Beginning of change, months | Weight gain, g (average data) | |
| irradiated | Control (not irradiated) | |||
| Decimeter (rats) | 10 | 2 | 95 | 120 |
| 10 cm (rats) | 10 | 1,5 | 25 | 70 |
| 10 cm (mice) | 10 | 1 | 0,5 | 2,9 |
| 3 cm (higher) | 10 | 1 | 42 | 70 |
| Millimeter (rats) | 10 | 3 | 65 | 75 |
Thus, in the entire range of microwave waves, the intensities (up to 10 mW/cm 2 = 10,000 μW/cm 2) cause, after 1...2 months, the weight of the irradiated animals to lag behind the weight of the control animals that were not exposed to radiation.
Thus, based on the results of studies of the impact of high-frequency electromagnetic fields of various ranges, the degree of danger of fields of various ranges was revealed, a quantitative relationship was established between this interaction and such field parameters as intensity or power flux density, as well as the duration of exposure.
For reference: modern Russian microwave standards (SanPiN 2.2.4 / 2.1.8.055-96, approved by the Decree of the State Committee for Sanitary and Epidemiological Surveillance of the Russian Federation dated May 8, 1996 No. 9) radiation (maximum permissible values of energy exposure per work shift) correspond to parameters given in tables 7, 8.
Table 7
Table 8
Maximum permissible levels of energy flux density in the frequency range of 300 MHz - 300 GHz, depending on the duration of exposure
Regardless of the duration of exposure, the intensity of exposure should not exceed the maximum value indicated in table 8 (1000 μW/cm2). It is characteristic that SanPiN, in contrast to the corresponding Soviet standards, does not mention the need to use goggles.
Table 9
Maximum permissible levels of RF EMR for the population, persons under 18 years of age, and women in a state of pregnancy
In addition to television stations and radar stations operating in a circular view or scanning mode;
++ - for cases of exposure from antennas operating in the circular view or scanning mode
Thus, the maximum allowable dose is only 10 times lower than that which, with systematic irradiation for 1 hour a day, after 1 ... 2 months, causes a slowdown in development in animals. Despite postulated by marketers and some authorities, and also condemned by their virtual continuation on the Internet - trolls, the alleged “harmlessness” of microwave radiation, nevertheless, for the categories of the population listed in Table 9, the maximum intensity of microwave radiation is an order of magnitude lower than for all the rest and is 10 μW/cm 2 . In the case of antennas operating in the circular view or scanning mode (that is, irradiating a person periodically) - 100 μW / cm 2. Thus, the norm, which was previously set for EVERYONE, is now valid only for pregnant women and minors. And everyone else will do the same. Well, that's understandable. Indeed, otherwise it would be necessary to completely change the concept and technology of cellular communications, as well as the Internet.
True, people stuffed with propaganda will immediately object: how, they say, so, there are no other technologies for communication now; do not return to wired communication lines. And, if you think about it, why not come back? Let's continue, however.
Characteristic is the paragraph 3.10 in the cited SanPiN, which states: “If the source of RF EMR is unknown, there is no information about the operating frequency range and operating modes, measurements of the RF EMR intensity are not carried out.”
Imagine what would happen if there was a similar rule in the Criminal Code: “if the person who committed the criminal act is unknown, there is no information about the means by which he carried out this act, a criminal case is not opened, no search is made for such a person”? It is clear that this paragraph legally establishes the impossibility (in case of an unknown source of microwave radiation) for citizens and other persons to apply to the Sanitary and Epidemiological Station and other bodies for the purpose of measuring the level of microwave radiation.
Indeed, evidence of the presence of a radiation source is, for example, the official address of a cell tower, an Internet provider, etc. If the address is unknown, as well as it is not known WHAT exactly is the source of radiation, its measurement, in accordance with paragraph 3.10, will not be carried out. Perhaps that is why its operators do not give accurate information about the location of their towers on the Iota helpline. So that, in which case, there was nothing to complain about.
Further, even if the address of a tower or another source of microwave radiation somehow became known, then again, it is necessary to find out the operating frequency range, as well as operating modes. All this is possible only with the use of special instruments - meters, which must have passed state verification. The list of such devices is kindly given in SanPiN (see table 10).
Table 10
The cost of such devices starts from $1000….2000. It is clear that not everyone can afford to buy such a device, and even periodically check it in the appropriate state body. The readings of various kinds of microwave field indicators, such as those that can be purchased, for example, in the Chip and Dip store (see below), of course, will not be taken into account. There is a lot of information about this on the Internet.
What can happen to a citizen (or the head of an organization - a legal entity), who, in the absence of data on the microwave source and frequency range, despite clause 3.10 of SanPiN, will persist and persistently convince the Sanitary and Epidemiological Station of the need for measurements? They can, of course, come and measure. Or they can tell the doctors. So that they take adequate, from their point of view, measures. By the way, a lot has been written about this on the Internet. By the way, it may be useful for someone (including some of our customers) as a means to eventually “mow down” from the army. But pleasant consequences, in any case, apparently, are few. On the other hand, there are also apparently a lot of people who have real mental problems and link these problems with microwave radiation, judging by some messages on the Internet. To protect against such, it is possible that clause 3.10 was introduced into SanPiN. So everyone thinks what he wants. Well, we will continue to talk about the results. scientific publications.
There are, of course (in the public domain), and the results of more modern scientific research. Let's say the group's research results Ukrainian researchers (dating back to 2010) who recorded the fact significant the influence of microwave radiation from a mobile phone and WiMAX at a flux density of more than 40 μW/cm 2 on human cells. Researchers have proven an increase in the CHG index, which indicates a decrease in the functional activity of cells and an increase in the likelihood of a mutation due to chromatin condensation in chromosomes.
The picture below is a copy of part of the first page of one of the scientific publications which discusses the results of this study. If you are interested, you can find and download this publication on the Internet or contact its authors directly.
There are others Scientific research, but, we repeat, here we do not aim to cover them even briefly, because this article does not at all pretend to scientific publication and is rather kind scientific council, no more. By the way, if you need help with preparing scientific publication you can contact us.
Therefore, in scientific(And, moreover, in a non-scientific) discussion, we do not intend to enter here. The article is intended only for those who already understand what's what in relation to microwave radiation. Forcibly (and even non-violently) to convince someone, you will agree, at least, is not serious. Then, if the overwhelming majority of citizens suddenly take it and understand how harmful what they sometimes use (eat, etc.) ... You understand what will happen then. And the state will have to harden the legislation, apply repressive measures (like those used in the United States, and in Europe too). Agree, why is this necessary? It is much easier to allow a situation where everyone will think what they want. The notorious "pluralism" of opinions is given to the people for a reason. There would be no need for it, and everyone would speak (more precisely, forgive me, almost everyone), as in distant times, in the same language.
So, in our article we will not talk about the harmful effects on the human body (for such an effect is obvious), but about how measure the level of microwave radiation.
The design of the microwave radiation meter
You can go two ways. The first, relatively simple, is to purchase a factory-made meter. However, the cost of a good meter at present (September 2014) is at least 10 ... 15 thousand rubles (or even more). If this is the simplest meter, like the one shown in the figure below. Link to store address:
The indicator, no doubt, is convenient and pleasant in appearance. But, unfortunately, the seller does not even give the frequency range of microwave radiation, which he is able to measure. In addition, the minimum level of microwave radiation that this indicator can measure is also unknown (in the operating instructions it is written that it is equal to 0. But zero is an extensible concept: is it 10 -10 μW / cm 2? Or at least 10 -2 mW / cm 2?) In addition, subsequently, such devices tend to change their readings uncontrollably. Finally, in order to measure microwave radiation from 5 GHz, as a rule, a device of a different price range is needed. Of course, it will be needed when the measurement results need to be proved. officially. In addition, the scale of such a meter in a given frequency range is, as a rule, proportional to the power measured by it. In addition, he measures the microwave not in “parrots” (as home-made), but, say, in μW / cm 2.
True, there is one drawback with factory meters: not all of them have good sensitivity, since they are designed to measure already SUCH levels that are considered dangerous (or harmful) contemporary official medicine. In addition, “inexpensive” meter models do not make it possible to set the direction of radiation.
If anyone wants to make a homemade meter, please, there is a very inexpensive constructor (containing ready-made parts and blocks that will only be soldered together) from Master Kit (more details can be found on the website http://www.masterkit.ru). However, it shows the level of microwave radiation only in two modes: “less than permissible” and “more than permissible” (in the latter case, the LED on the device case lights up). It is clear that such a primitive indication is hardly relevant.
Therefore, the second way is to make your own device, fortunately, this is not so difficult. The only thing that may be difficult is the microwave diode. This is a diode that is able to detect (rectify) a signal at a microwave frequency. With the exception, perhaps, of Moscow and a number of other cities, you won’t be able to buy such a diode in stores like “Electronics” (you can, of course, for fun, ask the sellers if they have at least an idea what kind of diode it is in general ... only do not confuse it with a magnetron from a microwave oven). And it will be possible to buy it, except by placing an order. Moreover, not every electronics store will undertake to fulfill it. So it is best to place an order either in an online store ... or go to Moscow, for example, to the Mitinsky radio market. There will definitely be no problems with this. The most inexpensive microwave diode suitable for a meter can cost from 20 rubles. (used, of course). But this is not very scary: as a rule, Soviet-made microwave diodes (D405 type) are fully operational even after they are disposed of due to the expiration of their service life (including by selling at a bargain price on the radio market). It should be noted that they used to belong to defense products (at present, there are more modern and functional analogues); their characteristic feature is that after a certain number of hours of operation they begin to lose their characteristics, therefore it is necessary to replace them periodically. In addition, it is highly undesirable to take them by the metal parts with your hands if the person is not grounded: the fact is that they are afraid of static electricity and the breakdown voltage in the opposite direction is only 15 ... 30 V.
The cost of a new diode will be from 100 rubles. It is better to buy several - different modifications and experiment which one is best for your device.
So, a decision was made - to solder a home-made microwave meter. According to what scheme? Let's just say that there are many such schemes on the Internet. Unfortunately, ALL (that we have seen) they are not suitable for the reason that they indicate only modulated changes the amplitude of the received microwave signal (sometimes referred to as beats), rather than the amplitude itself. And they are simply not working.
Plot of signal with constant amplitude
Graph of a signal with varying amplitude
In addition, these designs are often not very simple. Therefore, it is worth trying to make the scheme proposed below. Let's say right away that it does not pretend to be economical and compact. Electronics specialists, of course, will laugh at its primitiveness and underdevelopment ... But, there is only one most important advantage to it: it works and measures the amplitude of the microwave signal, and not just its modulated change. More precisely, it allows you to measure the relative magnitude of the voltage amplitude in the received microwave signal.
How is that relative? In other words, the device takes measurements in “parrots”; of course, it is difficult to talk about Volts per meter or μW / cm 2 here (although an attempt is made below). But graduation is an approximate, MINIMUM estimate of the actual level of radiation. Although, knowing a minimum is not bad. If, say, this "minimum" is 100...1000 μW/cm 2 , then it makes sense to comprehend the existing state of affairs. Although, we repeat, in a sense it is easier - to comprehend nothing at all and live like . In fact, problems with the health and well-being of a particular person are his and, basically, only his problems. True, there are still his relatives.
The fact is that for accurate graduation of the scale of this device, a calibrated generator of the appropriate frequency is required. Moreover, it will be necessary to calibrate not at one frequency, but at least several (5 ... 10). If there is no generator at hand or you do not want to deal with the laborious calibration process, then it is quite possible to use, for example, a cell phone operating in signal transmission mode (voice or data over the Internet) as a signal against which measurements will be carried out; radio Internet modem (for example, Beeline or Iota), a working Wi-Fi network. Having experimented with these sources of microwave radiation, it will then be easy for you to navigate with others, for example, passing (driving) past a cell tower or being somewhere in a metal-covered (quiet horror, by the way, sometimes !!) supermarket, subway, etc. .d. Then, just like a magic box, the reasons why it “suddenly”, “for no reason”, a breakdown appeared, became nauseated, a headache (this is, in part, signs of microwave radiation), etc. . However, we will talk about this a little later.
Caution: when soldering, do not bring this unit too CLOSE to a working microwave oven. For there is a danger of ruining the microwave diode. At least take care of the device (it seems that if a person does not care about his health, then it costs CHEAPER than the device), as soon as you spent time and energy on its creation.
So, first let's look at the electrical circuit diagram.
Structurally, the circuit consists of several blocks: a measuring head, power supplies, a microammeter block, as well as a board where the rest of the circuit is assembled.
The measuring head is a half-wave vibrator with D405 diodes attached to it (or similar in characteristics, which allows rectifying microwave currents), D7 diodes, and a 1000 pF capacitor. All this is mounted on a plate of thick non-foil textolite.
A half-wave vibrator is two pieces of a pipe with a diameter of 1 cm made of non-magnetic metal (for example, aluminum) 7 cm long. The minimum distance between the ends of the tubes is approximately 1 cm or even less (so that a VD7 diode fits between them). In extreme cases, if there are no such tubes, you can get by with a piece of thick (from 2 mm) copper wire. The maximum distance between the ends of the tubes is 15 cm, which corresponds to half the wavelength for a frequency of 1 GHz. Note that the larger the diameter of the tubes (or wires), the less the half-wave vibrator is affected by distortions in the magnitude of the received signal, depending on the change in its frequency.
The design of the half-wave vibrator can be any. It is only important that good electrical contact be maintained between the diode electrodes and the ends of the tubes. For this purpose, it is advisable to close the ends closest to each other with non-magnetic metal plugs by drilling holes in them with diameters of 8 mm and 3 mm, respectively, to a depth of 3 ... 5 mm. We used brass tips. But you can, for example, fill the ends of the tubes to a depth of 1 cm with tin or solder, then drill holes of the indicated sizes in it.
In our device, a VD7 diode of the D405 brand was used. The technical characteristics, as well as the dimensions of this diode, are given below (taken from the reference book “Semiconductor devices. High-frequency diodes, pulse diodes, optoelectronic devices: Handbook / A.B. Gitsevich, A.A. Zaitsev, V.V. Mokryakov, etc.; Under the editorship of A.V. Golomedov.-M.: Radio and communication, 1988.-592 p.”.
The operating frequency of this diode corresponds to a wavelength of 3.2 cm (frequency 9.4 GHz). However, it can also operate at lower frequencies: at least measurements at 400 MHz (75 cm wavelength) have shown its performance. The cutoff high frequency for this diode is approximately 10 GHz (length 3 cm). Thus, a meter using this diode can measure microwave radiation with frequencies of 400 MHz ... 10 GHz, which covers the range majority currently used household devices that emit microwaves: cell phones, blue-tooth, microwave ovens, Wi-Fi, routers, modems, etc. There are, of course, phones of the new standard (20…50 GHz). However, to measure radiation at such frequencies, firstly, another (higher frequency) diode is required, and, secondly, a different design of the measuring head (not in the form of a half-wave vibrator).
The diode is rather low-power, therefore, large fluxes of microwave radiation cannot be measured with it, otherwise it will simply burn out. Therefore, be more careful when measuring radiation from microwave ovens, as well as other powerful sources of microwave radiation! Those who voluntarily use the microwave oven for its intended purpose, of course, do not care about their health (this is their choice). But the device is at least worth saving.
Two D7 diodes in the measuring head, connected back to back, are designed to protect the VD7 diode from breakdown by static electricity (for example, if you accidentally touch the tubes of a half-wave vibrator with an electrified hand). Of course, these diodes will not withstand a high-power static discharge; for this purpose, either more powerful diodes or additional protection should be designed. However, when measuring at home, on the street, at work, with neighbors and acquaintances, this was not necessary. The main thing is to use the device carefully.
Current-voltage characteristics of diodes D7 are given below
Current-voltage characteristics of diodes D7
It can be seen that a small spread of parameters is observed from sample to sample. So, the I–V characteristics for different diodes D7 are shifted relative to each other by 0.04 V.
Thus, at a voltage not exceeding 0.5 V, both diodes will open, which will insure the VD7 diode from the critical (30 V) reverse voltage (when exposed to a microwave wave in a non-conductive period), caused, for example, by static electricity. On the other hand, even at an input voltage of 10 mV, the currents through the D7 diodes will not exceed a few tenths of a microampere. For a more accurate conclusion, the interpolation of the current-voltage characteristics of the diodes was carried out in the range of 0 ... 0.35 V. It turned out that for an input voltage of 10 mV, the current through the diode is no more than 7.4 nA. In this case, the input impedance of the meter (taking into account the fact that the input impedance of the selected operational preamplifier exceeds 50 MΩ) will be at least 10 * 10 -3 / (2 * 7.4 * 10 -9) = 576676 Ohm = 0.57 MΩ. The degree of accuracy (defined as the value of the coefficient of determination) of the interpolating trends for the used diodes D7 was less than R 2 =0.9995, i.e. almost equal to 100%.
Thus, the measuring head is an antenna (half-wave vibrator) and an amplitude detector based on an operational preamplifier. Moreover, the vibrator is loaded on a load with high resistance, significantly exceeding its wave resistance at frequencies of 300 MHz ... 3 GHz. It seems, as follows from the theory of antennas, this is wrong, because the power received by the antenna (vibrator) must be equal to the power that is absorbed in the load. However, this state of affairs is good when the task is to obtain the maximum efficiency of the radiation receiver. Our task is to realize, if possible, the independence of the meter readings from the magnitude of the impedance of the antenna (more precisely, the measuring head). And the efficiency, in principle, is completely unimportant. This is precisely what is provided if
Rin measuring head<< R нагрузки .
As a load, of course, we have an amplifier (input resistance of the K140UD13 microcircuit and two D7 diodes connected in parallel). That is why the first amplification stage is made on an operational amplifier, and, say, not on a bipolar transistor.
Capacitor C1 is designed to accumulate an electric charge when exposed to a microwave wave in a non-conducting period (this is a common element of detecting devices).
Thus, a rectified (relatively constant) voltage is obtained at the output of the measuring head.
The power sources are two sets of two Krona-type batteries, each with a voltage of 9 V (so that each set gives a voltage of 18 V).
Of course, one set of two batteries could have been dispensed with by decoupling the power supply (or even with one battery, by implementing a circuit that increases the voltage), but, to be honest, there was no desire to save money; the main goal was to quickly create working construction. If the device is not switched on for continuous operation, then during episodic measurements, the need to replace the batteries does not arise very often. For continuous operation, it is advisable to use a stationary power source.
The microammeter block is actually a microammeter and a variable resistor R9. It is necessary microammeter with scale up to 10 µA rather than a milliammeter. Although, of course, you can use microammeters with other scales, for example, up to 100 μA. If this is not available in a store in your city, then, again, you can order it via the Internet or go to a radio store in Moscow.
Current-voltage characteristic of a microammeter with a scale of up to 100 μA
Finally, consider the main block. It is a printed circuit board on which the actual circuit of the DC voltage amplifier received from the measuring head is assembled. The basis of the amplifier is a precision DC operational amplifier implemented on the K140UD13. This microcircuit is an operational DC preamplifier of the MDM type. This operational amplifier, one might say, stands apart from the vast majority of its “colleagues”. For they are intended, as a rule, to enhance variable voltage, and K140UD13 enhances constant (or slowly changing variable). The pin numbering of this chip is shown below:
Pin assignment K140UD13:
1 - common;
2 - inverting input;
3 - non-inverting input;
4 - supply voltage -Up;
5 - demodulator;
6 - exit;
7 - supply voltage + Up;
8 - generator capacity; 
The K140UD13 should be powered by voltages of +15 V and -15 V, respectively.
This operational amplifier allows you to measure currents from 0.5 nA, i.e. the sensitivity is very high.
Foreign analogue: µ A727M
It is the feature that this microcircuit enhances constant, but not variable current, and makes it possible to measure the value voltage amplitudes microwave radiation (rectified by the measuring head detector) as opposed to modulated voltage amplitude changes, as do the designs that can be found on the Internet. But there are cases when it is necessary to measure the unmodulated background of microwave radiation. So, microwave radiation from a cell phone, included in the mode of receiving and transmitting information, but in the absence of such a transmission (for example, if silence occurred during a conversation) will be much less modulated than if it was present.
At the inputs 2, 3 of the operational amplifier are the same diodes D7, connected in opposite directions. Their purpose is exactly the same as the diodes VD5, VD6. Why duplication?
The fact is that the measuring head is connected to the device by means of a flexible wire (for this purpose, we used a telephone twisted wire - in the form of a spiral). So, it may turn out that during the measurement process, when the measuring head is moved by the experimenter's hand (in order to determine the direction of its maximum sensitivity), the flexible wire is subject to bends. Gradually, he can break away from the device. At this point (because the sheath of the wire is made of an electrically non-conductive material), there is a high possibility of a discharge of static electricity between the flexible wire and one of the inputs of the operational amplifier, which will lead to its failure. After all, the maximum value of the input common-mode voltage of the K140UD13 circuit is only 1 V. We observed a similar case, so it was decided to make a second protection - already directly inside the device case, by soldering two back-to-back diodes closer to terminals 2, 3 of the operational amplifier.
By the way, it is also impossible to do without this protection alone (without one in the measuring head): if the flexible wire breaks, static electricity can damage, respectively, the VD7 diode. Therefore, double protection is necessary. If you do not make protection, then, most interestingly, the elements of the meter may not completely fail, but only partially. Those. the scheme will somehow work there. At the same time, if you continue to use the microwave meter for its intended purpose, you can get quite fantastic results. The funny thing is that in many of the schemes available today on the Internet, there is no protection at all.
On transistors VT1, VT2, reference voltage sources are assembled, giving +15 V and –15 V at the outputs, respectively. Of course, it was possible to get by with two microcircuits such as imported L7815, L7915 or Russian KR1158EN15 voltage stabilizers, but, again, the circuit was assembled quickly. Of course, using ready-made regulators, the circuit would be MUCH more economical than its actual version.
The resistances R2, R4 in the reference voltage sources are designed in case the zener diodes VD1, VD2 suddenly burn out so that the reference voltage does not exceed 16.5 V and the operational amplifier DD1 does not fail. Resistors R5, R6 also serve this purpose. The choice of the values of these resistances was carried out experimentally, by simulating the failure of the zener diodes VD1, VD2.
Details C2, C3, R5 are selected in accordance with the typical connection diagram. Capacitors C2, C3 are necessary to set the operating mode of the operational amplifier. Resistance R5 is necessary in case of a short circuit in the load of the operational amplifier: the fact is that the minimum allowable load resistance for it is 20 kOhm.
Capacitor C4 is designed to smooth out the ripples of the amplified voltage supplied from the output of the operational amplifier (so that the microammeter needle does not twitch when measuring a rapidly changing signal). Although, this capacitor is optional. Accordingly, the resistance R8 is designed to enable the discharge of this capacitor in the event that the microammeter block is disconnected from the main unit (board), for example, as a result of a break or poor contact of the connecting wires during subsequent inaccurate repairs or upgrades of the device.
Finally, the microammeter block consists of the microammeter itself and a variable resistor that regulates the voltage supply to the microammeter. The current-voltage characteristic (for example, a microammeter with a scale of 0 ... 100 μA is taken) is given above.
Regarding the assembly of the circuit. Since there are no particularly critical parts in the circuit, with the exception of VD7, an operational amplifier and a microammeter, it is assembled in the usual way. As for the VD7 microwave diode, it should be noted that it must be VERY carefully connected to the measuring head. First, it DOES NOT solder. You just need to ensure reliable tight contact with the vibrator tubes.
Secondly, when installed in a vibrator, it is advisable to short-circuit its electrodes, for example, with a piece of foil. And remove it only when the diode is fully installed in the holes drilled in the plugs of the vibrator tubes.
If you purchase a NEW D405 diode (or similar), then it will be in a special lead capsule, such as a cartridge case from a small-caliber rifle. This is done so that during transportation and storage (in the distribution network) the diode does not fail as a result of exposure to static electricity or powerful electromagnetic radiation. Therefore, it is necessary to take the diode out of the capsule when installing it in the measuring head very carefully, minimizing contact with its electrodes. Best of all, slightly removing it and pressing the electrode remaining in the sleeve, immediately connect the electrode that has appeared from the sleeve with the foil to the sleeve body itself. I hope it is clear that first the foil should be applied to the sleeve, and THEN to the electrode. Having removed the diode from the sleeve, it should immediately be connected (short-circuited) with the help of foil to its electrodes and only then installed. These precautions will help save it. By the way, the same applies to the operational amplifier. It is advisable to short-circuit all the electrodes before soldering it into the printed circuit board, which can be done, for example, by pressing a crumpled piece of foil between the electrodes; it is advisable to remove the foil only when the circuit on the printed circuit board is completely ready.
And further. microwave diodes by no means it is forbidden check for breakdown with a tester, ohmmeter, etc.! For such a “check”, most likely, will lead to a loss of the nominal performance of the diode. Moreover, the most interesting thing is that it may not completely lose its working capacity. However, the detection of a microwave signal will be much worse (an order of magnitude decrease in sensitivity is possible). According to the mind, of course, you should shoot the current-voltage characteristic of this diode in order to make sure that it is fully operational.
For the purpose of additional precautions, it is advisable to ground yourself during the assembly of the measuring head by putting on a special grounding bracelet on your leg and arm, as recommended by GOST when assembling electronic devices.
Remarks. As already mentioned, the K140UD13 scheme is preamplifier. Its amplification factor, according to the passport, is not less than 10, but in any case, not 100 and not 1000. Therefore, a significant increase in the signal received from the microwave measuring head cannot be expected. Therefore, by the way, a microammeter was used. If weaker signals need to be measured, then at least one more amplification stage should be added to the circuit. Since the K140UD13 is built using the MDM (modulator-demodulator) technology, its output is no longer a constant, but an alternating voltage. To smooth it, a C4-R7 filter is provided. Therefore, any other operational amplifier can be used to amplify the output voltage of a DC amplifier. So, if you remove the resistance R7 from the circuit by connecting the input of the next operational amplifier instead (for example, K140UD7), then you can get a significant gain. A device implemented in this way - a microwave meter can be used not only for direct measurements of (dangerous) levels of microwave radiation, but also for searching for weak microwave sources in the range of 400 MHz ... 10 GHz. True, in order to measure microwave radiation with frequencies above 4 ... 5 GHz, it is necessary to use a shorter wave vibrator. It is more efficient, of course, to manufacture a broadband directional microwave antenna of small dimensions, for example, a log-periodic one. When the desire arises, we will write about it.
A high gain will allow, for example, to detect hidden microwave devices (telephones, modems, various listening devices operating in real time). If there is a desire to use the meter for these purposes, it should be finalized. Firstly, for such purposes, a highly directional antenna, for example, a horn or log-periodic antenna, is most appropriate (in order to determine the direction of the microwave radiation source). Secondly, it would be advisable to take the logarithm of the output signal of the amplifier. If this is not done, then if someone nearby calls on a cell phone while searching for a source of a weak signal, the microammeter may fail (burn out).
For reference, we present the current-voltage characteristic of the considered device (microwave meter). 
The dependence was taken by applying a constant voltage in the range of 2.5 ... 10 mV to the input of the K140UD13 operational amplifier and taking microammeter readings. Due to the lack of a voltmeter of sufficient accuracy (load clamps MASTECH T M266F were used), it was not possible to measure the voltage at the input with a value lower than 2 ... 2.5 mV, so the current-voltage characteristic of the meter at lower input voltages was not taken.
It can be seen that in the range of 0 ... 3 mV it, oddly enough, is a little non-linear (although this may be the result of a systematic measurement error, because these clamps, of course, do not belong to the category of professional tools). The influence of a certain measurement error is also noticeable (its value is not reflected on the graph), which caused the deviation of the measured points from a straight line (trend) in the linear region (3...10 mV).
Microwave radiation meter calibration
Is it possible to carry out at least an approximate calibration of this meter? The flux density of microwave energy incident on the antenna is calculated as follows: 
W is the power of the microwave radiation flux, W / m 2,
E - electric field strength at the vibrator,
U in - voltage between the far ends (length) of the vibrator, V,
L eff - effective length, depending on the geometry of the receiving antenna of the meter and the received frequency, m. 160 mm (0.16 m).
This formula is valid for a lossless antenna placed above a perfectly conductive ground and delivering all the received power to the load (receiver). However, as already noted, in our case, the power delivered to the load is minimal (since the efficiency is very low). Therefore, the density of the microwave radiation flux, determined from the readings of the meter's microammeter and recalculated according to this formula per μW/cm 2 , will be lower than the actual one. In addition, the real design of a half-wave vibrator cannot be called an ideal antenna, because the real design performs signal reception worse (i.e., the efficiency of a real antenna is below 100%). Thus, using this formula, we obtain the minimum estimate of the power of the microwave flux incident on the measuring head.
The function of the dependence of the meter readings on the input voltage (determined from the dependency graph, see figure):
I and \u003d 0.9023U in + 0.4135
I and - current (according to the microammeter of the meter), µA,
U in - input voltage at the input of the amplifier, mV
Consequently
U in \u003d (I and -0.4135) / 0.9023
The calculation results were as follows (see Table 11).
Table 11
Approximate correspondence of indications on the meter scale (in microamperes) to the values of radiation power in μW / cm 2
| U in, mV (for reference) | 0,65 | 1,76 | 2,87 | 3,97 | 5,08 | 6,19 | 7,30 | 8,41 | 9,52 | 10,62 |
| Meter readings, µA | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| W, μW / cm 2 | 4,4 | 32,0 | 85,1 | 163,7 | 267,7 | 397,2 | 552,1 | 732,5 | 938,3 | 1169,6 |
Thus, the deviation of the instrument needle by even 1 ... 2 divisions (microamperes) already indicates a dangerous level of microwave radiation. If the arrow deviates to the full scale (i.e. the device went off scale), then the radiation level is definitely VERY dangerous (exceeds 1000 μW / cm 2). Staying where such a level is present is permissible only for 15-20 minutes. By the way, in accordance with even modern sanitary standards (not to mention Soviet ones), the level of microwave radiation in a place where people are, even for a short time, should not exceed the specified (limiting) value.
Results of measurements of microwave radiation
Attention! The information below is given as if for thought and is in no way official and / or documentary. This information is absolutely unsubstantiated! Based on this information, no conclusions can be drawn regarding the background of microwave radiation! In order to obtain official information, interested persons should contact the Sanitary and Epidemiological Station. It has special devices that have passed state certification and verification - microwave meters and the readings of only such devices can be taken seriously by the relevant state authorities.
Now consider, perhaps the most interesting - the results of using this device. The measurements were taken in 2010-2012. The data will be given not in µW / cm 2, but in microamperes (µA) on the scale of the meter.
Appliances. All of the devices listed below were turned on for receiving and transmitting data (or conversation). The radiation level of a Nokia GSM cell phone when measured, when the distance between it and the VD7 diode located in the measuring head is 20-30 cm, is 1...3...5 µA. Note that the signal fluctuates significantly in magnitude; it is maximum in dialing mode. Approximately the same level (but slightly more) of radiation gives the Iota Internet modem; for a Hyndai Curitel phone of the CDMA 450 standard, the radiation is 1.5 ... 2 µA (because it has a lower operating frequency, respectively, a higher radiation power). A signal of 7…8 µA was also observed outside the city. More modern phones give a slightly lower level. But, not much smaller.
By the way, when a phone operating in the receive-transmit mode is brought close to the measuring head, a signal of 5 or more µA is periodically observed, sometimes reaching 10 µA. Whereas at a distance of 40 ... 50 cm the level of the measured signal decreases significantly and is no more than 0.2 ... connections). Apparently, the level of microwave radiation in the near zone decreases in proportion not to the square of the distance, but faster. Therefore, the solution for those who cannot give up a cell phone is to use the so-called hands-free. Measurements showed that no radiation is transmitted through the hands-free wire. The presence of this wire does not affect the readings of the microwave radiation meter. The results of measurements made with the hands-free earpiece near the measuring head are the same as without hands-free at all. Therefore, the common Internet arguments of various kinds of trolls ("radio engineers" and other marketers) that hands-free wires, as well as the telephone network, can transmit a microwave signal, do not correspond to reality and are gossip. The reason for this may be that these wires are very thin (so thin that it is sometimes difficult to even solder them) and therefore have a high ohmic resistance. In addition, in order to transmit a microwave signal, it is necessary, firstly, at first to accept, i.e. the hands-free wire should act as an antenna. However, the antenna from it turns out to be unimportant. For it, along with a small thickness, has a high length (exceeding several wavelengths of microwave radiation from a cell phone). In addition, such a wire is somewhat twisted during operation, which causes its considerable inductance, apparently sufficient to significantly reduce the level of the microwave signal received by it. Secondly, the signal received by such an "antenna" must still be able to (re)radiate. The reradiation from the hands-free wire will be even lower for the reasons just mentioned. Therefore, hands-free use protects against microwave radiation from a cell phone. Compared to the radiation experienced by the head of a doomed person who is talking on a cell phone, pressing it close to his head, his (radiation) level decreases 10 or more times when using hands-free - this is on the microwave meter scale. If we switch to units of μW/cm 2 , then the power level will decrease approximately by a factor of 100 or more. I think this is very significant.
Also gossip is the possibility of using telephone lines to transmit microwave radiation. Although, we note that such a transmission through electric wires is quite possible, because we observed at one time, however, only in ONE place, near one of the electric wires with a cross section of 2.5 mm 2, located at a height of 2.2 m from the floor, despite its significant length. Wherein periodically there was also a small background of microwave radiation in the living rooms, as well as from one of the computer monitors (the old model - the vacuum beam type), while it was turned on. Then such signals disappeared (well, after some expedient measures). Despite its great length, the electric wire could still act as a receiver - emitter of radiation.
Measurements in the apartment (located at a distance of 200 m from the nearest cell tower) of one of the acquaintances, made at his personal request, showed a generally funny picture. The apartment in some places turned out to be full of microwave radiation at a level of 1 ... 4 µA. Of course, there were also places where it was absent altogether. At some points in space, as if for no reason, antinodes of microwave waves were present. Oddly enough, one of them was ... in the area of \u200b\u200bhis bed, at a height of 20 ... 40 cm from the pillow). Apparently, this is caused by interference and the formation of standing microwave waves. Well, maybe there were other reasons, because an employee lived in the apartment. We do not know anything about this, and the acquaintance, in his words, was not aware of it.
A microwave oven (we don’t remember the brand, unfortunately) gave an average level of microwave radiation of 5 ... 6 µA at a distance of another 3 (!) m from it, and the signal continued to grow briskly when trying to get further closer (I didn’t want to get closer for two reasons : there was no desire to be irradiated, and there was a fear for the device). A further opportunity to be irradiated was soon and very kindly provided to the owners of this microwave oven. In fact, well, after all, someone has to MOVE the economy by acquiring microwave ovens too. Indeed, with each microwave oven purchased by a Russian citizen taxes are paid to the state budget(!), wages are paid sellers in stores, drivers (delivering these ovens), receives his money and advertising develops etc. And if a person has already acquired a microwave oven, then let him use it later. How else? It is illogical, after all, to acquire things only for the purpose of quickly getting rid of them.
When traveling in the city of Ufa. If you drive up to microwave towers, the signal level often increases sharply, then, at a distance of 300-400 meters from the tower, it drops (on average for the surveyed towers). For example, on st. Bakalinskaya, when moving down towards the street. Mendeleev there is a turn to the left. So, for 300-400 meters, while we are passing this turn, the level of microwave radiation was observed to be 7 ... 8 µA, sometimes the device even went off scale (with the resistance R7 brought to maximum sensitivity). It seems that, as we understand, somewhere there is a tower of the Iota provider. No matter how we tried to find out (orally) from the operators of its help desk, the Iota company did not give us exact information about the location of the towers. Apparently, this is a commercial, and even a state secret. True, the question remains: WHY conceal something? On the one hand, the vast majority of people don't care at all. People are used to it. Headache, loss of strength is much easier and more effective to treat with pills than by avoiding sources of microwave radiation. Modern medicine has already substantiated this, one might say. On the other hand, Iota's competitors (Internet providers, Beeline, MTS) apparently already know very well where its towers are located, if only because they have not only microwave radiation meters, but also spectrum analyzers, radio frequency scanners. Or, as it sometimes happens, is there somewhere, in one of the upper apartments of the nearby high-rise buildings, there is, under the guise of a private residence, an ILLEGAL office of an Internet provider? There is information on the Internet that such cases take place among Internet providers and mobile operators. In any case, such secrecy is alarming.
But, there are also towers from which the signal level decrease extends further. At the television center, for example, on Zaki-Validi street (at a distance of about 600 m from the television center tower), a level of 6 ... 10 µA was observed.
Interestingly, by the way, the situation is with the fences. Metal, of course, reflects all radiation from itself. Near such fences, results that are interesting, from the point of view of physics, were sometimes observed. So, as a result of (apparently) interference, the level of microwave radiation near the metal places of the fence increased significantly.
Wooden fences, for example, fences (seemingly - against all odds), are also sometimes effective reflectors of microwave radiation. Although, in theory, they should have passed it without much attenuation. Along them, microwave radiation, emanating, for example, from the nearest cell tower, seems to slide and somewhat concentrate, increasing in level. The maximum level of microwave radiation in this case is located at a distance of the surface, approximately equal to 15...50 cm (one or more wavelengths). By the way, at a height of 4 ... 5 m, microwave radiation is approximately 2 ... 3 times higher. What is caused, apparently, by its much lower absorption at such heights - compared with a height of 0.5 ... 1.5 m from the earth's surface. For at a height of 4 ... 5 m there are fewer building structures, fewer tree branches (by the way, trees are an EFFECTIVE barrier that absorbs and scatters microwaves, reducing its level; not shrubs, but, we emphasize, namely, tall trees with thick trunks), no cars, people, etc. So think carefully before cutting down a tree, even if it obscures the windows. Perhaps this is your savior from the microwave.
In supermarkets and shops in Ufa. Paradoxically, the situation is different. Somewhere - the level of microwave radiation is not weak (3 ... 4 µA constantly), and somewhere - almost calm. Where exactly, of course, we will not say. For the broad mass of our readers, it seems, is useless. In fact, EVERY person in the city cannot visit ALL supermarkets and shops, right?
When traveling in the city of Chishmy (Republic of Bashkortostan). There, of course, a true PARADISE - in comparison with Ufa (not to mention the villages ... though ...). We found only a few places in Chishmy, and even then, the radiation power near each is not as high as in Ufa. Maximum, a level of 4…5 µA was observed.
Well, in conclusion
In order not to end the article on technical features and microamps. Let's talk about life-affirming, bright and positive. Remember the poem by N.A. Nekrasov "Railway?" The poet, in the end, nevertheless showed a gratifying, LIGHT side, right? So, there is one friend, a very good person. Somehow a conversation with him came about microwave radiation, its effect on the body. So this man brought a life-affirming, "killer" argument: "yes, everything is nonsense; I served in the army in the signal troops. So there, by mistake of one of the repairmen, poor-quality shielding of one cable was made. As a result, in the barracks for more than than half a year, the level of microwave radiation exceeded the permissible norms by more than a hundred times. And, as you can see, nothing. I'm not impotent (I have two children), etc. What do I need this microwave oven and, moreover, a telephone ". The tragedy is that this man is only 52 years old, and he has already ... in recent years he has difficulty walking due to gradually developing necrosis of the hip joint, and in the future, as doctors say, it will be even worse; and the spine is clearly not in order. I’ll make it, he says, somehow until retirement, 3 years left ... And then they will cut off his leg, insert a titanium prosthesis there and sew it on again. So there are no hopeless situations!
And then ... probably, it's all a coincidence, apparently, he's right. Indeed, in fact, for example, when a person is shot at point-blank range with a pistol and then he (in the sense of a person, not a pistol) falls, then this can also be called a coincidence, looking from the side: the shot was fired by a pistol, and a man fell. These are completely different things. Well, the bullet has nothing to do with it at all. And really, what is there, some kind of small, unfortunate bullet, but can it really cause a fall of a person whose mass is 10,000 times higher? Now, if not a person fell, but pistol- then everything would be logical and explainable.
Yes, here, before I forget, is another example of such a coincidence. About 7-8 years ago (in the early 2000s), a Hyndai Curitel phone with an operating frequency of 450 MHz, CDMA standard (provider - our Ufa Sotel) was used as an Internet modem on a computer. The speed, of course, is VERY low, but the connection was absolutely stable and trouble-free, unlike the different Beeline and Megafon modems there (which were also in our operation and soon, after 3-4 months, were thrown into a landfill). By the way, if anyone wants, it is quite possible to test the quality of such modems. Well, then go troll on the Internet, pretending to talk about the quality of communication. By the way, if necessary, you can tentatively. But, the conversation is not about that.
And about the cat
Which, having sensed microwave radiation (it also gives heat to the body), began to periodically warm up at this phone when it was turned on for receiving / transmitting data. By the way, despite the fact that she was periodically driven away from the phone, she returned to it again (which, by the way, vividly reminded us of those people who, one might say, have grown together with a cell phone and even sleep, holding it in bed next to them) . By the way, the situation resembles one goat. They say that goats, and especially goats, are smart animals. So one of them, as soon as the welders started work, constantly came and literally stared at the welding with literally hatched eyes ... apparently, trying to understand for himself a new, hitherto unknown to him, natural phenomenon. Like some people, he was probably also a technology leader, a supporter of technical innovation. Well, from his own, goat's point of view, of course. The welders told the owner (he, of course, zero attention), drove away, kicked the goat - everything was useless. Every time, as they said, he will come, get up and look (from a distance of about a few meters). And soon his eyes popped out.
So, the phone was lying on a chair, being at a distance of 1 m from the computer (the network cable no longer allowed; now, after getting acquainted with the information about the effect of microwaves on living organisms, we do not operate modems at such low distances at all). So, the cat, having sensed heat (and, it must be said, that the heat, which is the action of a microwave, is felt as "penetrating", as embracing a warm stream - if the radiation has sufficient power, of course), lay down on a chair with visible pleasure, rubbed its head against phone, purred, lay down and belly. Then, when a way was found to move the phone away from the computer (on the street), the cat began to go there and again lay down next to it when it worked. It was like that for a year and a half. In direct contact with the phone, the cat's head or stomach received radiation corresponding to 5...10 µA (on the scale of the microwave meter discussed above). The radiation dose received per week was approximately 5 hours. During this period, kittens were often born dead, sick, with "oddities" (for example, with a wound in the stomach that did not want to heal for a long time). Moreover, the cat gave birth to them with difficulty, during the fights she screamed a lot, rushed around the apartment in different directions (although earlier the birth proceeded normally), as a result, the kittens lay scattered all over the house. There were few healthy kittens. Then they stopped using this phone, another Internet modem was used for the Internet, operating at a higher frequency. Yes, and the cat somehow lost interest in microwave radiation (apparently, it turned out to be more intelligent than a considerable part of citizens - people). After that, kittens began to be born, it seems, without any problems. There are far fewer dead and sick now. True ... she had one strange property. Sometimes she gives birth to kittens in different places. And she is in no hurry to go feed them if they are not in her place. Kittens can lie down for so long, meowing, to the point of death. But if you bring them to the cat, she, somehow with discontent, but nevertheless, feeds them, as if nothing had happened. Previously, she sometimes, of course, could also leave them in different places. But at least she came to feed, regardless of where they lay. And now it's not in a hurry.
Those. maternal instinct she got a failure; seems to be for the rest of your life. By the way, a similar failure is observed, for example, in chickens grown in an incubator. They can start hatching chickens, as if sitting on eggs. And then, all of a sudden, just stop doing it, forgetting about it. As a result, the embryos in the eggs are underdeveloped and die. Yes, and chickens raised in an incubator differ significantly in their activity from those hatched by a chicken: the latter were barely born - and you can hardly catch them. And the incubators - they are so meek ...
So allegations that supposedly cats do not like microwave radiation are nonsense. As it turned out, even as they love, even to the detriment of themselves and their offspring (an analogy with smoking and some other habits in humans suggests itself here). True, this applies to 450 MHz radiation, we do not know what about higher (more harmful) frequencies - up to 30 ... 100 GHz. Indeed, after all small doses of microwave radiation are used even in medicine. For it has been established that they contribute (at the initial stage) to the activation of vital processes in the body, can carry out effective heating of organs, etc. By the way, why did the cat like radiation from the phone? In our opinion, the point here is that any cell phone (operating in the mode of receiving and transmitting a signal) radiates not only its fundamental frequency (equal to 450 MHz - in this case), but also other so-called upper harmonics. The frequencies of some of these harmonics are in the terahertz (and possibly higher) range, i.e. close to the infrared region of the spectrum. It was these infrared harmonics, apparently, that attracted the cat - at first, because she did not immediately feel the harm from the microwave. Yes, by the way, to be precise, in medicine, i.e. in physiotherapy, not microwave radiation is used, but infrared, with frequencies above 300 GHz, which, unlike the range of 0.5 ... 50 GHz, can have a healing effect. True, with the low-frequency part of the infrared spectrum (up to 100 ... 200 THz) it is better not to experiment for a long time. During perestroika (more precisely, the destruction of the USSR), there were reports in the press that, for example, researchers made similar generators ... and then they themselves broke them - due to the development of diseases in those who were in close contact with them. Despite the seemingly not too high power of those generators. As for radiation with frequencies above 300 THz, this is already ordinary thermal radiation, visible light, etc. It's much safer. True, only up to the ultraviolet region. Radiation of higher frequencies, on the contrary, is even more harmful and destructive for living organisms (and for humans too).
But only for initial stage. Then - everything is the other way around: the body begins to break down. True, unlike a pistol shot (when the destruction of the body occurs instantly and therefore is immediately obvious), low-power microwave radiation acts gradually, according to the principle "a drop hits a stone", simultaneously introducing a functional imbalance in the body. For example, when microwave radiation of sufficient power is applied to the lens of the eye, microdamages first appear in it, which do not affect vision at all and are therefore imperceptible. Over time, they get bigger. But, they say, there is nothing wrong here. Let's look at the situation with: after all, a person is not eternal. For the time being, these various injuries will accumulate there - and then it’s time for him to retire. Well, when you are already retired, everyone will say so there: look, they say, in your passport and remember how old you are. So, you can see for yourself how logical and optimistic everything is.
These are such coincidences... And, stand up, over the past decades, we have also revealed the following: every time the sun rises, for some reason it becomes light. And when it sets, on the contrary, everything plunges into darkness and for some reason night comes. Moreover, historians, astronomers, and other scientists report that this was observed before, many thousands of years ago ... So, you see, how many different coincidences.
With respect to you.
