Reviews and useful information for radio amateurs. VHF and UHF bands Frequencies 144

Just a short time ago, mostly home-made equipment was used to operate in the 144-145 MHz range. VHF transverters were popular among radio amateurs, many of which were comparable in size to the transceiver used with it. Radio amateurs converted decommissioned industrial VHF radio stations of the Palma type to the amateur VHF 145 MHz band, obtaining a radio station operating on several channels.

Then “Viols”, and later “Mayaks”, operating on forty channels, became available to radio amateurs. These radio stations then looked simply fantastic in their capabilities!

Currently, you can relatively inexpensively purchase multi-channel portable VHF transceivers from world-famous companies - “YAESU”, “KENWOOD”, “ALINCO”, which in terms of their parameters and ease of operation are significantly superior to both home-made equipment in the 145 MHz range and converted industrial equipment - “Palms” ", "Beacons", "Violas".

But to work through a repeater from home, office, while driving or working from a car, you need an antenna that is more effective than that used in conjunction with a portable “rubber band” radio station. When using a stationary "branded" VHF station, it is often advisable to use a homemade VHF antenna with it, since a decent "branded" outdoor 145 MHz antenna is not cheap.

This material is dedicated to the production of simple homemade antennas suitable for use with stationary and portable VHF radio stations.

Features of 145 MHz antennas Due to the fact that for the manufacture of antennas in the 145 MHz range, thick wire is usually used - with a diameter of 1 to 10 mm (sometimes thicker vibrators are used, especially in commercial antennas), antennas in the 145 MHz range are broadband. This often allows you to design the antenna exactly according to specified sizes do without her additional settings

on the 145 MHz band. To tune antennas in the 145 MHz range, you must have an SWR meter. It could be like homemade device , and industrial production. On the range 145 Bridge antenna resistance meters are practically not used, due to the apparent complexity of their correct manufacture.

Although, with careful manufacturing of the bridge meter and, therefore, its correct operation on this range, it is possible to accurately determine the input impedance of VHF antennas. But even using only a pass-through SWR meter, it is quite possible to tune homemade VHF antennas. The power of 0.5 W, which is provided by imported portable radio stations in the “LOW” mode and domestic portable VHF radio stations such as “Dnepr”, “Viola”, “VEBR”, is quite enough to operate many types of SWR meters. The “LOW” mode allows you to tune antennas without fear of failure of the output stage of the radio station at any input impedance of the antenna.

Before you start tuning the VHF antenna, it is advisable to make sure that the SWR meter readings are correct. It is a good idea to have two SWR meters designed to operate in 50 and 75 Ohm transmission paths. When setting up VHF antennas, it is advisable to have a control antenna, which can be either a “rubber band” from a portable radio station or a homemade quarter-wave pin. When tuning an antenna, the level of field strength created by the tuned antenna is measured relative to the control one. This makes it possible to judge the comparative efficiency of the tuned antenna. Of course, if you use a standard calibrated field strength meter for measurements, you can get an accurate estimate of the antenna's performance. When using a calibrated field meter, it is easy to measure the antenna radiation pattern. But even using homemade field strength meters during measurements and having obtained only a qualitative picture of the distribution of electromagnetic field strength, one can fully draw a conclusion about the efficiency of the tuned antenna and approximately estimate its radiation pattern.

The simplest outdoor VHF antenna (Fig. 1) can be made using an antenna operating in conjunction with a portable radio station. On the window frame, from the outside (Fig. 2) or from the inside, a metal corner is attached to an extension wooden block, in the center of which there is a socket for connecting this antenna. It is necessary to strive to ensure that the coaxial cable leading to the antenna is of the minimum required length. 4 counterweights, each 50 cm long, are attached to the edges of the corner. It is necessary to ensure good electrical contact between the counterweights and the antenna connector with the metal corner. The radio's shortened twisted antenna has an input impedance of 30-40 ohms, so a coaxial cable with a characteristic impedance of 50 ohms can be used to power it. Using the angle of inclination of the counterweights, you can change the input impedance of the antenna within certain limits, and, therefore, match the antenna with the coaxial cable. Instead of the branded “elastic band,” you can temporarily use an antenna made of copper wire with a diameter of 1-2 mm and a length of 48 cm, which is inserted into the antenna socket with its sharpened end.

Figure 1. Simple outdoor VHF antenna

Figure 2. Design of a simple outdoor VHF antenna

A VHF antenna made of coaxial cable with the outer braid removed. The cable is embedded in an RF connector similar to the connector of a “proprietary” antenna (Fig. 3). The length of the coaxial cable used to make the antenna is 48 cm. This antenna can be used in conjunction with a portable radio station to replace a broken or lost standard antenna.

Figure 3. Simple homemade VHF antenna

To quickly manufacture an external VHF antenna, you can use a connecting coaxial cable 2-3 meters long, which is terminated with connectors corresponding to the antenna socket of the radio station and antenna. The antenna can be connected to such a piece of cable using a high-frequency tee (Fig. 4). In this case, a rubber band antenna is connected from one end of the tee, and counterweights 50 cm long are screwed on from the other end of the tee, or another type of radio ground for the VHF antenna is connected through the connector.

Figure 4. Simple remote VHF antenna

Homemade antennas portable radio

If the standard antenna of a portable radio station is lost or broken, you can make a homemade twisted VHF antenna. To do this, use a base - polyethylene insulation of a coaxial cable with a diameter of 7-12 mm and a length of 10-15 cm, on which initially 50 cm of copper wire with a diameter of 1-1.5 mm is wound.

To tune a twisted antenna, it is very convenient to use a frequency response meter, but you can also use an ordinary SWR meter. Initially, the resonant frequency of the assembled antenna is determined, then, by biting off part of the turns, shifting, pushing apart the turns of the antenna, the twisted antenna is tuned to resonance at 145 MHz.

This procedure is not very complicated, and by setting up 2-3 twisted antennas, a radio amateur can configure new twisted antennas in literally 5-10 minutes, of course, if the above-mentioned devices are available. After setting up the antenna, it is necessary to fix the turns either with electrical tape, or with a cambric soaked in acetone, or with a heat-shrinkable tube. After fixing the turns, it is necessary to once again check the frequency of the antenna and, if necessary, adjust it using the upper turns.

It should be noted that in “branded” shortened twisted antennas, heat-shrinkable tubes are used to fix the antenna conductor.

Half-wave field antenna For efficient work

However, with low powers supplied to the antenna, quite satisfactory matching can be achieved using a P-circuit, similar to what is described in the literature. Scheme half wave antenna and its matching device is shown in Fig. 5. The length of the antenna pin is selected slightly shorter or longer than the L/2 length. This is necessary because even with a slight difference in the electrical length of the antenna from L/2, the active resistance of the antenna impedance decreases noticeably, and its reactive part by initial stage increases slightly. As a result, it is possible to match such a shortened antenna using the P-circuit with greater efficiency than matching an antenna with a length of exactly L/2. It is preferable to use an antenna with a length slightly longer than L/2.

Figure 5. VHF antenna matching using a P-circuit

The matching device used air tuning capacitors of the KPVM-1 type. Coil L1 contains 5 turns of silver-plated wire with a diameter of 1 mm, wound on a mandrel with a diameter of 6 mm and a pitch of 2 mm.

Setting up the antenna is not difficult. By including an SWR meter in the antenna cable path and at the same time measuring the level of field strength created by the antenna by changing the capacitance of variable capacitors C1 and C2, compressing and stretching the turns of coil L1, we achieve the minimum readings of the SWR meter and, accordingly, the maximum readings of the field strength meter. If these two maximums do not coincide, you need to slightly change the length of the antenna and repeat its adjustment again.

The matching device was placed in a housing soldered from foil fiberglass with dimensions of 50*30*20 mm. When working from a stationary workstation of a radio amateur, the antenna can be placed in the window opening. When working in the field, the antenna can be suspended by its upper end from a tree using a fishing line, as shown in Fig. 6. A 50 ohm coaxial cable can be used to power the antenna. Using a 75-ohm coaxial cable will slightly increase the efficiency of the antenna matching device, but at the same time will require configuring the radio output stage to operate at a 75-ohm load.

Figure 6. Antenna installation for field use

Foil based window antennas

Based on adhesive foil used in security alarm systems, very simple designs of window VHF antennas can be built. This foil can be purchased with an adhesive base. Then, having freed one side of the foil from the protective layer, you simply press it against the glass and the foil instantly sticks securely. Foil without an adhesive base can be glued to the glass using varnish or Moment type glue. But for this you need to have some skill. The foil can even be secured to the window using adhesive tape.

With appropriate training, it is quite possible to make a high-quality soldered connection between the central core and braid of a coaxial cable with aluminum foil. Based personal experience, each type of such foil requires its own flux for soldering. Some types of foil can be soldered well even using only rosin, some can be soldered using soldering oil, other types of foil require the use of active fluxes. The flux must be tested on the specific type of foil used to make the antenna in advance of installation.

Good results are obtained by using a foil fiberglass substrate for soldering and attaching the foil, as shown in Fig. 7. A piece of foil fiberglass laminate is glued to the glass using Moment glue, the antenna foil is soldered to the edges of the foil, the cores of the coaxial cable are soldered to the copper foil of the fiberglass laminate at a short distance from the foil. After soldering, the connection must be protected with moisture-resistant varnish or glue. Otherwise, corrosion of this connection may occur.

Figure 7. Connecting the antenna foil to the coaxial cable

Let's analyze the practical designs of window antennas built on the basis of foil.

Vertical window dipole antenna

The diagram of a vertical dipole window VHF antenna based on foil is shown in Fig. 8.

Figure 8. Windowed vertical dipole VHF antenna

The quarter-wave pole and counterweight are positioned at an angle of 135 degrees to keep the antenna system's input impedance close to 50 ohms. This makes it possible to use a coaxial cable with a wave impedance of 50 Ohms to power the antenna and use the antenna in conjunction with portable radio stations, the output stage of which has such an input impedance. The coaxial cable should run perpendicular to the antenna along the glass for as long as possible.

Foil Based Window Loop Antenna

The frame window VHF antenna shown in Fig. will work more efficiently than a dipole vertical antenna. 9. When feeding the antenna from a side angle, the maximum radiated polarization is located in the vertical plane; when feeding the antenna in the bottom angle, the maximum radiated polarization is in the horizontal plane. But at any position of the feed points, the antenna emits a radio wave with combined polarization, both vertical and horizontal. This circumstance is very favorable for communication with portable and mobile radio stations, the position of the antennas of which will change while moving.

Figure 9. Frame window VHF antenna

The input impedance of the window loop antenna is 110 ohms. To match this resistance with a coaxial cable with a characteristic impedance of 50 Ohms, a quarter-wave section of coaxial cable with a characteristic impedance of 75 Ohms is used. The cable should run perpendicular to the antenna axis for as long as possible. Loop antenna has a gain approximately 2 dB higher relative to a dipole window antenna.

When made from foil window antennas with a width of 6-20 mm, they do not require tuning and operate in a frequency range much wider than the amateur band of 145 MHz. If the resulting resonant frequency of the antennas turns out to be lower than the required one, then the dipole can be adjusted by symmetrically cutting off the foil from its ends. The loop antenna can be configured using a jumper made from the same foil that was used to make the antenna. The foil closes the antenna sheet in the corner, opposite the power points. Once configured, contact between the jumper and the antenna can be achieved either by soldering or using adhesive tape. Such adhesive tape should press the jumper firmly enough to the antenna surface in order to ensure reliable electrical contact with it.

Significant power levels can be supplied to antennas made of foil - up to 100 watts or more.

Outdoor vertical antenna

When placing an antenna outside a room, the question always arises of protecting the opening of the coaxial cable from atmospheric influences, using a high-quality antenna support insulator, moisture-resistant wire for antennas, etc. These problems can be solved by making a protected outdoor VHF antenna. The design of such an antenna is shown in Fig. 10.

Figure 10. Protected outdoor VHF antenna

A hole is made in the center of a 1 meter long plastic water pipe into which a coaxial cable can fit tightly. Then the cable is threaded there, protruded from the pipe, exposed at a distance of 48 cm, the cable screen is twisted and soldered at a length of 48 cm. The cable with the antenna is inserted back into the pipe. Standard plugs are placed on the top and bottom of the pipe. Moisture-proofing the hole where the coaxial cable enters is not difficult. This can be done using automotive silicone sealant or fast-curing automotive epoxy.

The result is a beautiful, moisture-proof, protected antenna that can operate under the influence of weather conditions for many years.

To fix the vibrator and antenna counterweight inside, you can use 1-2 cardboard or plastic washers, tightly placed on the antenna vibrators.

The pipe with the antenna can be installed on a window frame, on a non-metallic mast, or placed in another convenient place.

Simple coaxial collinear antenna

A simple collinear coaxial VHF antenna can be made from coaxial cable. To protect this antenna from atmospheric influences, a piece of water pipe can be used, as described in the previous paragraph. The design of a collinear coaxial VHF antenna is shown in Fig. eleven.

Figure 11. Simple collinear VHF antenna The antenna provides a theoretical gain of at least 3 dB greater than a quarter-wave vertical. It does not require counterweights for its operation (although their presence improves the performance of the antenna) and provides a directivity pattern close to the horizon. A description of such an antenna has repeatedly appeared on the pages of domestic and foreign amateur radio literature, but the most successful description was presented in the literature. Antenna dimensions in Fig. 11 are indicated in centimeters for a coaxial cable with a shortening factor of 0.66. Most coaxial cables with polyethylene insulation have this shortening factor. The dimensions of the matching loop are shown in Fig. 12. Without the use of this loop, the SWR of the antenna system may exceed 1.7. If the antenna is tuned below the 145 MHz range, you need to shorten the upper section slightly, if higher, then lengthen it. Certainly,

Figure 12. Dimensions of the matching loop

Despite the large size of the plastic pipe required to protect this antenna from atmospheric influences, the use of a collinear antenna of this design is quite advisable. The antenna can be moved away from the building using wooden slats, as shown in Fig.

13. The antenna can withstand significant power supplied to it, up to 100 watts or more, and can be used in conjunction with both stationary and portable VHF radio stations. Using such an antenna in conjunction with low-power portable radio stations will give the greatest effect.

Figure 13. Collinear Antenna Installation

Simple collinear antenna

This antenna was assembled by me similar to the design of a car remote antenna used in a cellular radiotelephone. To convert it to the 145 MHz amateur band, I proportionally changed all the dimensions of the “telephone” antenna. The result was an antenna, the diagram of which is shown in Fig. 14. The antenna provides a horizontal radiation pattern and a theoretical gain of at least 2 dB over a simple quarter-wave pin.

A coaxial cable with a characteristic impedance of 50 Ohms was used to power the antenna.

Figure 14. Simple collinear antenna

A practical antenna design is shown in Fig. 15. The antenna was made of a whole piece of copper wire with a diameter of 1 mm. Coil L1 contained 1 meter of this wire, wound on a mandrel with a diameter of 18 mm, the distance between the turns was 3 mm. When the design is made exactly to size, the antenna requires virtually no adjustment. It may be necessary to slightly adjust the antenna by compressing and stretching the coil turns to achieve a minimum SWR. The antenna was placed in a plastic water pipe. Inside the pipe, the antenna wire was fixed using pieces of foam plastic.

This antenna can be considered as a shortened HF antenna with a central extension coil. Indeed, the antenna resonance measured using a bridge resistance meter in the HF range turned out to lie in the frequency region of 27.5 MHz. Obviously, by varying the diameter of the coil and its length, but maintaining the length of the winding wire, you can ensure that the antenna operates both in the VHF range of 145 MHz and in one of the HF bands - 12 or 10 meters. To operate on the HF bands, it is necessary to connect four counterweights with a length of L/4 for the selected HF band to the antenna. This dual use of the antenna will make it even more versatile.

Experimental 5/8 wave antenna

When conducting experiments with radio stations in the 145 MHz range, it is often necessary to connect the antenna under test to its output stage in order to check the operation of the radio station’s receiving path or to adjust the transmitter output stage. For these purposes, I have been using a simple 5/8 wave VHF antenna for a long time, the description of which was given in the literature.

This antenna consists of a section of copper wire with a diameter of 3 mm, which is connected at one end to an extension coil and the other to a tuning section.

A thread is cut at the end of the wire connected to the coil, and at the other end a tuning section made of copper wire with a diameter of 1 mm is soldered. The antenna is matched with a coaxial cable with a characteristic impedance of 50 or 75 Ohms by connecting to different turns of the coil, and the tuning section can be slightly shortened. The antenna diagram is shown in Fig. 16. The antenna design is shown in Fig. 17.

Figure 16. Diagram of a simple 5/8 wave VHF antenna

Figure 17. Design of a simple 5/8 wave VHF antenna

The coil contains 10.5 turns of wire with a diameter of 1 mm. The coil wire is evenly distributed throughout the frame. The outlet to the coaxial cable is made from the fourth turn from the grounded end. The antenna vibrator is screwed into the coil, a contact lamella is inserted under it, to which the “hot” end of the extension coil is soldered. The lower end of the coil is soldered to the antenna ground foil. The antenna provides SWR in the cable no worse than 1:1.3. Tuning the antenna is carried out by shortening its upper part with pliers, which is initially made slightly longer than necessary.

I conducted experiments on installing this antenna on window glass. In this case, a vibrator initially 125 centimeters long made of aluminum foil was glued to the center of the window. The same extension coil was used and was installed on the window frame. The counterweights were made of foil. The ends of the antenna and counterweights were bent slightly to fit on the window glass. A view of a 5/8 window - wave VHF antenna is shown in Fig.

18. The antenna is easily tuned to resonance by gradually shortening the vibrator foil using a blade, and gradually switching the coil turns to a minimum SWR. The window antenna does not spoil the interior of the room and can be used as a permanent antenna for operating on the 145 MHz band from home or office.

Figure 18. Window 5/8 - wave VHF antenna

Efficient portable radio antenna

In cases where communication using a standard rubber band is not possible, a half-wave antenna can be used. It does not require “ground” for its operation and when working over long distances it provides a gain of up to 10 dB compared to a standard “rubber band”. These are quite realistic figures, considering that the physical length of a half-wave antenna is almost 10 times longer than the rubber band.

Figure 19. Half-wave VHF antenna with matching device

The circuit coil contains 5 turns of silver-plated copper wire with a diameter of 0.8 mm, wound on a mandrel with a diameter of 7 mm along a length of 8 mm. Setting up the matching device consists of tuning the circuit L1C1 into resonance using the variable capacitor C1, and using the variable capacitor C2 to regulate the connection of the circuit with the output of the transmitter. Initially, the capacitor is connected to the third turn of the coil from its grounded end. Variable capacitors C1 and C2 must have an air dielectric.

For the antenna vibrator, it is advisable to use a telescopic antenna. This will make it possible to carry the half-wave antenna in a compact folded state. This also makes it easier to configure the antenna together with a real transceiver. When initially setting up the antenna, its length is 100 cm. During the setup process, this length can be slightly adjusted according to

better job

antennas. It is advisable to make appropriate marks on the antenna so that you can subsequently install the antenna directly to the resonant length from its folded position. The box where the matching device is located must be made of plastic in order to reduce the capacitance of the coil to “ground”; it can be made of foil fiberglass. This depends on the actual operating conditions of the antenna.

The antenna is tuned using the field strength indicator.

Using an SWR meter, tuning an antenna is advisable only if it is not operated on the radio body, but when an extension coaxial cable is used in conjunction with it. When operating the antenna twice on the radio body and using an extension coaxial cable, two marks are made on the antenna pin, one corresponding to the maximum field strength level when operating the antenna on the radio body, and the other mark corresponds to the minimum SWR when using an extension coaxial cable with the antenna. Usually these two marks are slightly different.

Very simple to implement and easy to configure is a continuous half-wave VHF antenna, the design of which is shown in Fig. 20. Gamma matching is used to power it through a coaxial cable. The material from which the antenna vibrator and gamma matching are made must be the same, for example, copper or aluminum. Due to the mutual electrochemical corrosion of many pairs of materials, it is unacceptable to use different metals to perform the antenna and gamma matching.

Figure 20. Continuous half-wave VHF antenna

If a bare copper tube is used to make the antenna, then it is advisable to adjust the gamma matching of the antenna using a shorting jumper as shown in Fig. 21. In this case, the surface of the pin and the gamma matching conductor is carefully cleaned and using a bare wire clamp as shown in Fig. 21a achieve a minimum SWR in the coaxial antenna power cable. Then, at this point, the gamma matching wire is slightly flattened, drilled and connected with a screw to the antenna surface, as shown in Fig. 21b. It is also possible to use soldering.

Figure 21. Setting up gamma matching of a copper antenna

If an aluminum wire from a power electrical cable in plastic insulation is used for the antenna, then it is advisable to leave this insulation to prevent corrosion of the aluminum wire by acid rain, which is inevitable in urban environments. In this case, the gamma matching of the antenna is adjusted using a variable capacitor, as shown in Fig. 22. This variable capacitor must be carefully protected from moisture. If it is not possible to achieve an SWR in the cable of less than 1.5, then the gamma matching length must be reduced and the adjustment must be repeated again.

Figure 22. Setting up gamma matching of an aluminum-copper antenna

If you have enough space and materials, you can install a continuous vertical wave VHF antenna. The wave antenna works more efficiently than the half-wave antenna shown in Fig. 20. A wave antenna provides a radiation pattern more close to the horizon than a half-wave antenna.

The wave antenna can be matched using the methods shown in Fig.

When making these antennas, it is desirable that the coaxial power cable be perpendicular to the antenna at least 2 meters. Using a balun in conjunction with a continuous antenna will increase its efficiency. When using a balun, it is necessary to use symmetrical gamma matching. The connection of the balun is shown in Fig. 24.

Figure 24. Connecting a balun to a continuous antenna

Any other known balancing device can also be used as an antenna balun. When placing the antenna near conductive objects, you may have to slightly reduce the length of the antenna due to the influence of these objects on it.

Round VHF antenna

If the placement in space of vertical antennas shown in Fig.

20 and fig. 23 in their traditional vertical position is difficult, they can be placed by folding the antenna sheet into a circle. The position of the half-wave antenna shown in Fig. 20 in a “round” version is shown in Fig. 25, and the wave antenna shown in Fig. 23 in Fig. 26. In this position, the antenna provides combined vertical and horizontal polarization, which is favorable for communications with mobile and portable radio stations.

Although, theoretically, the level of vertical polarization will be higher with the side feeding of round VHF antennas, in practice this difference is not very noticeable, and the side feeding of the antenna complicates its installation. The side feeding of the circular antenna is shown in Fig. 27.

Figure 25. Continuous round vertical half-wave VHF antenna

Figure 26. Continuous round vertical wave VHF antenna

Figure 27. Side feeding of round VHF antennas

When testing portable radios or working with them, sometimes there is not enough “just a little” power for reliable communication. I made a passive “amplifier” for portable VHF stations. A passive "amplifier" can add up to 2-3 dB to a radio station's on-air signal. This is often enough to reliably open the squelch of the correspondent station and ensure reliable operation. The design of a passive “amplifier” is shown in Fig. 28.

Figure 28. Passive “amplifier”

The passive “amplifier” is a fairly large tinned coffee can (the bigger the better). A connector similar to the antenna connector of a radio station is inserted into the bottom of the can, and a connector for connecting to the antenna socket is sealed into the lid of the can. 4 counterweights 48 cm long are soldered to the can. When working with a radio station, this “amplifier” is switched on between the standard antenna and the radio station. Due to the more efficient “ground”, the strength of the emitted signal increases at the receiving site.

Other antennas can be used in conjunction with this “amplifier”, for example, an L/4 pin made of copper wire, simply inserted into the antenna socket.

Wideband survey antenna

Many imported portable radio stations provide reception not only in the amateur range of 145 MHz, but also in the survey ranges of 130-150 MHz or 140-160 MHz. In this case, for successful reception in the surveillance bands, where a twisted antenna tuned to 145 MHz does not work effectively, you can use a wideband VHF antenna. The antenna diagram is shown in Fig. 29 and the dimensions for different operating ranges are given in table.

Size A, cm

Size B, cm

Table 1. Wideband VHF antenna dimensions

To operate the antenna, you can use a coaxial cable with a characteristic impedance of 50 Ohms. The antenna sheet can be made of foil and glued to the window. You can make the antenna sheet from an aluminum sheet, or by printing it on a piece of foil fiberglass of suitable sizes. This antenna can receive and transmit in the specified frequency ranges with high efficiency.

Figure 30. Elementary zigzag antenna

The zigzag elementary antenna consists of a half-wave dipole antenna, which supplies voltage to the half-wave vibrators. In real antennas, up to five such half-wave vibrators are used. Such an antenna has a narrow radiation pattern pressed to the horizon. The type of polarization emitted by the antenna is combined - vertical and horizontal. To operate the antenna, it is advisable to use a balun.

In antennas used in service communication stations, a reflector made of a metal mesh is usually placed behind the elementary zigzag antennas.

The reflector ensures one-way directivity of the antenna. Depending on the number of vibrators included in the antenna and the number of zigzag antennas connected together, you can obtain the required antenna gain.

Radio amateurs practically do not use such antennas, although they are easy to make for the amateur VHF bands of 145 and 430 MHz. To make the antenna sheet, you can use aluminum wire with a diameter of 4-12 mm from a power electrical cable. In the domestic literature, a description of such an antenna, for the fabric of which a rigid coaxial cable was used, was given in the literature.

Kharchenko antenna in the 145 MHz range

The Kharchenko antenna is widely used in Russia for television reception and in official radio communications. But radio amateurs use it to operate on the 145 MHz band. This antenna is one of the few that works very efficiently and requires virtually no adjustment. The Kharchenko antenna diagram is shown in Fig. 31.

Figure 31. Kharchenko antenna

To operate the antenna, you can use either 50 or 75 Ohm coaxial cable. The antenna is broadband, operating in a frequency band of at least 10 MHz on the 145 MHz band. To create a one-way radiation pattern, a metal mesh is used behind the antenna, located at a distance of (0.17-0.22)L.

The Kharchenko antenna provides a lobe width of the radiation pattern in the vertical and horizontal planes close to 60 degrees. To further narrow the radiation pattern, passive elements are used in the form of vibrators 0.45L long, located at a distance of 0.2L from the diagonal of the frame square. To create a narrow radiation pattern and increase the gain of the antenna system, several combined antennas are used.

One of the most popular directional antennas for operating in the 145 MHz band are loop antennas. The most common in the 145 MHz band are two-element loop antennas. In this case, the optimal cost/quality ratio is obtained. The diagram of a two-element loop antenna as well as the dimensions of the perimeter of the reflector and the active element are shown in Fig. 32.

Figure 32. VHF loop antenna

Antenna elements can be made not only in the form of a square but also in the form of a circle or delta. To increase the radiation of the vertical component, the antenna can be fed from the side. The input impedance of a two-element antenna is close to 60 ohms, and both 50-ohm and 75-ohm coaxial cable are suitable for operation. The gain of a two-element VHF loop antenna is at least 5 dB (above the dipole) and the ratio of radiation in direct and reverse direction can reach 20 dB. When working with this antenna, it is useful to use a balun.

Circular polarized loop antenna

An interesting circularly polarized loop antenna design has been proposed in the literature. Antennas with circular polarization are used for communication through satellites. Double feeding of the loop antenna with a phase shift of 90 degrees allows you to synthesize a radio wave that has circular polarization.

The loop antenna power supply circuit is shown in Fig. 33. When designing an antenna, it must be taken into account that the length L can be any reasonable, and the length L/4 must correspond to the wavelength in the cable.

Figure 33. Circularly polarized loop antenna

To increase the gain, this antenna can be used in conjunction with a frame reflector and director. The frame must be powered only through a balun. The simplest balancing device is shown in Fig. 34.

Figure 34. The simplest balancing device

Industrial antennas in the 145 MHz range

Currently, you can find a large selection of branded antennas for the 145 MHz range on sale. If you have money, of course, you can buy any of these antennas. Please note that it is advisable to purchase solid antennas already tuned to the 145 MHz range. The antenna must have a protective coating to protect it from corrosion by acid rain, which can fall in a modern city. Telescopic antennas are unreliable in city operating conditions and may fail over time. silicone grease for waterproofing connectors, telescopic connections and screw connections in matching devices.

Literature

1. I. Grigorov (RK3ZK). Matching devices 144 MHz range//Amateur Radio.
2. HF and VHF.-1997.-No. 12.-P.29.
3. Barry Bootle. (W9YCW) Hairpin Match for the Collinear – Coaxial Arrau//QST.-1984.-October.-P.39.
4. Doug DeMaw (W1FB) Build Your Own 5/8-Wave Antenna for 146 MHz//QST.-1979.-June.-P.15-16.
5. S. Bunin. Antenna for communication through satellites // Radio.- 1985.- No. 12.-S.

20.

D.S.Robertson ,VK5RN The “Quadraquad” – Circular Polarization the Easy Way //QST.-April.-1984.-pages16-18.

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Classmates

Permitted VHF frequencies for radio amateurs and their purpose

FM, digital voice repeater only, transmission. Frequency ratings 145.600-145.775 MHz, step 12.5 kHz. Telegraphy, FM, digital voice communications. Mainly for space communications.

All types for space communications only. It turns out that for direct communication

in frequency modulation, frequencies from 145.206 MHz to 145.594 MHz are allocated. Grid step 12.5 kHz.

This table was compiled in accordance with the decision of the SCRF dated July 22, 2014 No. 10-07-01.

Until now, my experience with amateur radio has been limited exclusively to work on the shortwave bands (3-30 MHz). However, 2 meter VHF bands are also available to radio amateurs (aka “deuce”, 144-146 MHz) and 70 centimeters (430-440 MHz). Working in these ranges has some nuances. If you just buy a VHF radio and shout CQ on the calling frequency from the balcony, you will most likely not have the best experience. Below we will discuss what underwater rakes there are on VHF and how to avoid them. The terms VHF and UHF are often used. For some reason, the abbreviations VHF and UHF have not taken root in Russian, and they often say VHF, meaning both ranges. Further in the text, VHF will refer exclusively to the amateur radio VHF and UFH bands.

As you may know, HFs are refracted in the ionized layers of the atmosphere and return to Earth. Thanks to this, radio communications over thousands and even tens of thousands of kilometers are possible on HF. VHFs don't work that way. Tropospheric passage is possible for them, but this phenomenon is relatively rare. Therefore, communication on VHF is usually possible on short distances, typically about 100 km. When using “exotic” types of communication (for example, via satellites), it is possible to conduct QSOs over significantly longer distances. But these types of communications deserve their own separate articles, so let’s forget about them for now.

VHF may not be suitable for long-distance communications, but in terms of stability they have no equal. If there is a connection on VHF, then it is there 24/7, regardless of transmission, and without any fading, lightning, and so on. In addition, on VHF there are no problems with high level noise on the air and pileups.

The presence of obstacles between correspondents (tall buildings, mountains, and so on) prevents VHF radio communications. However, in urban environments, radio communications are possible by reflecting radio signals from buildings. Let's say your balcony faces east and there is a tall building nearby. This building can play the role of a reflector, with the help of which it will be possible to contact a correspondent located in the west. Obstacles can also be bypassed with the help of repeaters, which we will discuss below.

Wavelengths in the VHF range are significantly shorter than in the HF range. Due to this, VHF antennas are more compact. As a result, wearable and car radios. In addition, on VHF it is possible to build directional antennas with a high gain of a completely sane size.

To all that has been said, it should be added that VHF is usually used in FM. This is not that it is very important, but it is another difference from HF, where SSB is used.

Choosing a transceiver

There are quite cheap Chinese-made radios for VHF, for example from Baofeng. But with such walkie-talkies, you will find a number of inconveniences - low quality microphone and speaker, limited functionality and an interface inconvenient for amateur radio purposes, short battery life, low strength of the case, and so on. But the worst thing is that such walkie-talkies are often not designed to work with an external antenna installed on the roof or balcony, and the antenna is on the walkie-talkie itself extremely ineffective.

The problem is that Baofengs are not full-fledged analog transceivers, but are built on the basis of the RDA1846 integrated circuit (datasheet). This circuit has a relatively small dynamic range on blocking. This means that if you connect an external antenna to your walkie-talkie, the receiver will likely be blocked by strong signals from local TV and radio stations. Theoretically, this can be solved using additional filters. But from a practical point of view, it is much easier to use a walkie-talkie from another manufacturer, for example, Yaesu, ICOM or Kenwood.

Important! There is a good chance that you will not make any radio communications using any Baofeng UV-5R. Tested by personal bitter experience.

When choosing a transceiver, it would be a good idea to look for reviews of the models you are interested in. Many radio amateurs post such reviews on YouTube. I previously provided a list of recommended YouTube channels in the note Let’s go through the quest to obtain a call sign and register a regional electronic zone. If a new transceiver does not fit into your budget, it makes sense to familiarize yourself with advertisements for the sale of used transceivers, for example, on the qrz.ru bulletin board.

This is exactly how I purchased my walkie-talkie, Kenwood TH-D72A (manual):

This is far from new, but a very high-quality device. It is especially interesting because it is almost the only this full duplex walkie-talkie. That is, while you are transmitting in the 2 m range, the walkie-talkie can continue to receive and reproduce the signal on the second channel in the 70 cm range (with the DUP function enabled). This is especially convenient when working with those very “exotic” types of communications.

The radio also has GPS, APRS support and probably some others useful features, which I haven’t figured out yet. Like most portable radios, Kenwood TH-D72A operates at a power of no more than 5 W. As we will soon see, this is quite enough for working on VHF.

Fun fact! Even though the walkie-talkie is no longer in production, Kenwood continues to release firmware updates for it.

Given the uniqueness of the walkie-talkie, the fact that the owner sold it together with charger KSC-32, PTT SMC-34, spare battery and case, and extremely attractive price, the purchase was made without any hesitation. The transaction went smoothly - the device arrived quickly and in fully working condition.

Making an antenna

The default antennas on most portable radios are useless. The Kenwood TH-D72A antenna is no exception. The EU1KY antenna analyzer shows the following SWR graphs:

When constructing such graphs, it is necessary to hold on to the body of the antenna analyzer. The fact is that for normal operation the antenna needs human body, acting as a counterweight. If you don't hold onto the body, the graphics will turn out even worse. As you can see, the resonance missed the mark a little at two, only at “some” 15 MHz, and at 70 cm the SWR does not fall below 2.4. Overall, the antenna is pretty bad.

It was decided to make a full-size antenna for the 2-meter range and place it on the balcony. Firstly, such an antenna will not have any questions about its effectiveness. Secondly, it will be possible to safely work on a two-wheeler in the winter, being warm and comfortable. Thirdly, for safety reasons, there should be no people near the antenna during transmission. Now this is not so critical, since I am running at 5 watts. But in the future I can get a more powerful transceiver.

A diagram of a suitable antenna made from RG58 cable was found on the blogs of Australian radio amateurs John, VK2ZOI and Andrew, VK1NAM:

The antenna is an ordinary dipole, only located vertically. Unlike HF, VHF requires monitoring of polarization. Typically, radio amateurs use vertical polarization on VHF, which is why a vertical dipole is required. The cable core plays the role of the upper arm of the antenna, and the outer side of the cable screen plays the role of the lower arm. The cut-off choke consists of nine turns of cable on a 25 mm frame.

Fun fact! Sometimes VHF is used in CW and SSB, and it is customary to use horizontal polarization. However, most modern VHF transceivers only support FM. CW and SSB are mainly supported in transceivers capable of operating on both HF and VHF. Examples of such transceivers include the Yaesu FT-991A and ICOM IC-7100.

Digital modes of communication also work, with the difference that they are used for long-distance communications, and therefore polarization is not important.

The antenna was made a little longer than indicated in the diagram, and then trimmed to the minimum SWR on the range:

As you can see, the antenna has a relatively good resonance at 70 cm. In this range it operates at the third harmonic. Is not best antenna for 70 cm, if only for the reason that the cut-off choke is completely not designed for this frequency. In particular, when the antenna is powered through a couple of meters of coaxial cable, the SWR graph changes significantly. But if necessary, the antenna allows radio communications in this range (tested!).

After setup, the antenna was completely placed in a PVC pipe. The pipe was closed at both ends with pieces of sponge, and covered with a lid on top. I printed the lid on a 3D printer, but a kefir lid or a piece of fiberglass would work just as well. All holes except the bottom one were sealed with epoxy. I did not seal the bottom hole in case moisture somehow got into the antenna. In this situation, it will have somewhere to drain.

The antenna was mounted on the balcony in the same way as I had previously mounted the OPEK HVT-400B HF antenna:

Unlike HF, the RG58 cable is not suitable for VHF to power antennas. RG213 or even lower loss cable should be used instead. When using 10 meters of RG58, the signal attenuation at 144 MHz is 1.82 dB, and at 450 MHz it is 3.65 dB. For RG213 it is 0.86 dB and 1.73 dB, respectively. However, if the cable is short, just a couple of meters, then RG58 will do.

Let's go on air

The calling frequency in the 2 meter range is 145.500 MHz. Just come in and make a general call, just like on HF. They don't always answer. But if you call without much fanaticism in the morning before work and in the evening after, then people regularly answer. Of course, provided that you use a normal transceiver, an effective antenna, and the correct cables, as described above.

At 70 cm everything is a little more interesting. The official general calling frequency is 433.500 MHz. However, this frequency falls in the LPD range 433.05-434.79 MHz and in Moscow there is the strongest interference. The alternative frequency is 432.500 MHz. But this frequency falls within the range of 430-433 MHz, which is prohibited from being used within a radius of 350 km from the center of Moscow. As far as I could find out, there is an agreement among Moscow radio amateurs to use 436.500 MHz as a calling frequency. You can also try the so-called “pharmacy” frequency, 436.600 MHz.

Fun fact! Just like on HF, there are radio hooligans on VHF, many of whom behave, let’s say, incorrectly on air. My life philosophy is that if you meet such a person on the air, don’t talk to him about anything and make sure that you are as far away in frequency as possible :)

Experiments show that in urban environments the 2 meter range works noticeably better range 70 cm. Although radio communications can be carried out both there and there. I also don’t exclude that the problem is in my antenna, which is not particularly designed to work at 70 cm.

We work through repeaters

VHF radio communications are often carried out through repeaters. A repeater is a device that receives your signal on one frequency and repeats it on another. Typically the repeater antenna is mounted somewhere high where it can receive signals from many radio amateurs, and the repeater transmits at high power. This is one of the reasons why it was said above that 5 W is quite enough for VHF operation. The task comes down to reaching the repeater. And it will already provide you with good power and coverage area.

Repeaters often “open” with a specific tone. Tone is a low-frequency signal that is mixed into your voice as it is transmitted. The main tone transmission standards are CTCSS and DCS.

The tone is not a password to the repeater. It's more of a foolproof feature. Let's say a radio amateur is located at an equal distance between two repeaters using the same frequencies. Using a tone, one of the repeaters can understand that a radio amateur is addressing it and receive the signal. The second repeater, using a different tone, will understand that the message is not addressed to him and will ignore the signal. Without tone, a radio amateur would work simultaneously on two repeaters, and, unwittingly, would interfere with the work of his colleagues.

The easiest way to find out about existing local repeaters is to ask local radio amateurs about them. You can also search through repeater catalogs, at least on the same qrz.ru. But the information in catalogs is often either outdated or simply incorrect.

It is clear that in order to work through a repeater, the radio must be configured accordingly. Let's look at this setting using a specific example. A radio amateur I know says that in your city there is a repeater with an input at a frequency of 145.050 MHz and transmission at 145.650 MHz (channel R2), tone 88.5 Hz. You are using Kenwood walkie talkie TH-D72A. The question is, how to get to the repeater?

Press VFO and set the frequency to 145.650 MHz. Go to MENU → Radio → Repeater → Offset Freq, enter here 0.6 MHz, that is, the difference between the frequency of transmission and reception of the repeater. Press the green F button, and then SHIFT (located on the asterisk symbol, to the left of zero). A plus sign lights up on the screen. It means that when transmitting, the previously specified offset frequency will be added to the current frequency. But we need the frequency to be subtracted. Press F again, then SHIFT. The plus sign changed to a minus sign. You can check that everything is working as expected by quickly pressing and releasing PTT. During transmission, the frequency should automatically change to 145.050.

Setting the tone. To do this, press TONE (located at number 8). The letter T lights up. This means that the radio will transmit the CTCSS tone, but will not require it to open the squelch. If you want the radio to check the tone when receiving, you can switch it from T mode to CT mode by pressing TONE again. In the same way, you can switch to using DCS instead of CTCSS. Next, press the F button. Proceed to selecting Tone Freq. Specify 88.5 Hz and save.

Now, in order not to lose the settings, press F, and then M.IN. Save it to a memory location. You can now switch from VFO mode to MR mode and switch between saved channels. This is much more convenient than constantly adjusting frequencies and tones manually. If desired, you can assign a name to the cell in MENU → Memory → Name (works only in MR mode). By long pressing MR you can switch to continuous scanning mode for saved channels.

If everything was done correctly, people on the repeater should now be able to hear you. You can check the connection to the repeater by briefly pressing PTT. After you release PTT, the repeater will continue to transmit the carrier for some time, which you will hear. If there is no carrier, then either the repeater is not receiving your signal, or the tone was incorrectly configured, or the repeater is not working. If there is a carrier, then everything is fine.

Fun fact! With some luck, it is possible to reach the repeater with 5 watts to the antenna located inside the house.

It is clear that when using a different radio, the settings will be different. But the principle will be the same, and I think you can figure it out without difficulty.

Conclusion

So, you're on VHF. Now what? You can stop there and just communicate for a living with radio amateurs living nearby. And you can learn how to use APRS, conduct radio communications via satellites or EchoLink, receive SSTV from the ISS, install your own repeater, experiment with antennas, filters, amplifiers, digital modes of voice transmission (D-STAR, C4FM, DMR), transceivers different manufacturers, and maybe homemade. You might even want to try EME, which is radio communications by bouncing radio waves off the Moon. Basically, you have a range of frequencies. What you will do with it is limited mainly by your imagination.

73 and see you on VHF!

Addition: Replacing the standard Kenwood TH-D72A antenna is discussed in the post

The conditions for using allocated radio frequency bands by category of amateur radio stations can be viewed

The main types of work of radio amateurs are: telegraph (CW), single-sideband telephone (SSB), chat telephone (VHF bands) and amateur radio teletype (RTTY).

Radio amateurs are allocated 10 sections of the DV, SV, HF bands:

2200 meters (135.7-137.8 kHz)
160 meters (1.81 - 2 MHz),
80 meter (3.5 - 3.8 MHz),
40 meter (7 - 7.2 MHz),
30 meter (10.1 - 10.15 MHz),
20 meter (14 - 14.35 MHz),
16 meter (18.068 - 18.168 MHz),
15 meter (21 - 21.45 MHz),
12 meter (24.89 - 24.99 MHz),
10 meter (28 - 29.7 MHz).

The frequency distribution for the VHF bands is as follows:

2 meters - 144-146 MHz
144000-144500 CW
144150-144500 SSB
144625-144675 Digital communications
144500-145800 FM
145800-146000 SSB
145800-146000 CW
70 cm - 430-440 MHz
430000-432500 CW
432150-432500 SSB
433625-433725 Digital communications
432500-435000 FM
438000-440000 FM
438025-438175 Digital communications
435000-438000 SSB
435000-438000 CW
23 cm - 1296-1300 MHz
1296000-1297000 CW
1296000-1297000 SSB
1297000-1298000 FM
1297000-1300000 FM
1296150-1297000 SSB
1296000-1297000 CW

Frequencies above 1.3 GHz
2400-2450 MHz
5650-5670 MHz
10.0-10.5 GHz
24.0-24.25 GHz
47.0-47.2 GHz
75.5-81.0 GHz
119.98-120.02 GHz
142-149 GHz
241-250 GHz

The amateur radio airwaves are never empty. At any time of the day you can hear amateur radio stations. However, on different amateur bands, the passage of radio waves has its own characteristics. Let's consider the conditions for propagation of radio waves in each amateur band.

HF transmission largely depends on the ability of radio waves to be reflected from the ionospheric layer. The reflection of radio waves of different frequencies from the ionosphere at the same time is different. Waves in low-frequency ranges are reflected more strongly, while high-frequency waves are reflected less strongly. Therefore, with weak ionization (for example, on a winter night), long-distance propagation in low-frequency ranges is possible. In this case, high-frequency waves pass through the ionosphere and do not return to Earth. When ionization is strong (for example, during the day in the spring), there are conditions for long-distance propagation in high-frequency ranges.

Band 1.8 MHz The most difficult range for long-distance communications. Until recently, it was completely wrong in Russia to leave it to beginners. Long-distance communication (over 1500-2000 km) is possible only under a special set of circumstances and for a limited time (half an hour to an hour), mainly at dawn-sunset. And communications up to 1500 km are possible after dark. At dawn the range freezes. In some countries the range is limited to just a few kHz. In Japan, for example, radio amateurs are allowed to operate within the range of 1815-1825 kHz.

Band 3.5 MHz is a pronounced nocturnal range. During the daytime, communication on it is possible only with nearby correspondents. As darkness falls, stations located at great distances begin to appear. Thus, in the European part of Russia, after sunset, stations in Ukraine, the Volga region, and the Urals appear. Then Vostochnaya stations can be heard, and by 23-24 hours Moscow time (according to the amateur radio code 23-24 MSK) - and Western Europe. A little earlier (especially in the winter months) it is possible for DX signals to appear from Asia (most often Japan), less often - Africa, and very rarely - Oceania. By 3-4 MSK, signals from stations in Canada, the USA and South America may appear, which, with good transmission, can be heard for some time after dawn. An hour or two after sunrise, the range becomes empty.

7 MHz band usually “lives” around the clock. During the day you can hear stations from nearby areas (in summer - at a distance of 500-600, in winter - 1000-1500 km). DX signals appear in the evening and night hours. Japanese, American and Brazilian amateurs work quite a lot in this range, the signals of their radio stations travel especially well (in the European part of Russia) on winter nights at 1-5 MSK. Among European shortwave operators, the Yugoslavs, Romanians, Finns, and Swedes are especially willing to use the 7 MHz band. US radio amateurs are allowed to work in the 7.100-7.300 MHz range (in Europe, these frequencies are used by broadcast stations), and therefore SSB can only work with Americans on separate frequencies.

Band 14 MHz- the range in which the majority of radio amateurs operate. Passage on it (with the exception of winter nights) is available almost around the clock. Particularly good passage is observed in April-May. In the morning hours (4-6 MSK) in the European part of Russia, signals from stations in America and Oceania travel well. During the daytime, European stations are mainly heard; in the evening, signals from Asian and African stations appear.

Band 21 MHz also widely used by shortwave operators. Passage on it is mainly observed in the daytime. It is less stable than at 14 MHz and can change sharply. There are especially many Japanese amateur radio stations operating on SSB here: it is worth giving a general call during good progress to Japan, when several calling radio stations immediately appear on this frequency. Sometimes they create significant interference, interfering with the reception of other distant stations. Early in the morning (or, conversely, in the evening - depending on the transmission characteristics) on 21 MHz you can hear loud signals from American stations. During the day and in the evening, African stations - TR8, ZS, 9J2 - are usually clearly audible. Less often, VK and ZL pass at the same time.

Band 28 MHz lies on the "edge" of short waves. This is the most capricious shortwave range: a day or two of excellent transmission can suddenly give way to a week of complete absence. Signals from radio stations here can only be heard during the day, or more precisely, during daylight hours, with the exception of certain rare cases of anomalous propagation of radio waves, therefore communications are possible only between correspondents located in the sunlit zone of the Earth. Most often, on 28 MHz you can hear signals from African stations, Asia, and less often - Oceania. Sometimes in the evening, signals from US shortwave radio stations travel well in the European part. Of the European stations, the most active are F, G, I, DL/DJ/DK. Signals from Eastern European stations are relatively rare. The 28 MHz band is free from interference and is the most interesting for observations due to sudden changes in transmission. Its uniqueness is that if there is penetration, then even with the most minimal power you can manage connections for 10-12 thousand km. If there is no transmission, then the presence of a powerful transmitter will not help.

As for the remaining ranges of 10.1 MHz, 18.1 MHz and 24.9 MHz (they are also called WARC bands, thanks to the World Amateur Radio Conference at which they were assigned to radio amateurs), the passage on them is something between the ranges described above . One of the differences on the 10.1 MHz band is the use of only telegraph and teletype. And the transmission is very similar to 7 MHz, with the difference that during the day communications are possible over a distance of up to 2000-3000 km. And distant stations pass when it gets dark.

Frequency plan for HF bands (frequencies below 30 MHz) IARU Region 1, brought into compliance with Russian legislation in the field of communications

Range 2,200 meters:

Range 160 meters:

Range 80 meters:

Range 40 meters:

Range 30 meters:

SSB transmissions are permitted to radio stations directly involved in traffic intended to save lives.

The radio frequency band 10120 - 10140 kHz can be used for SSB transmissions in Africa south of the equator during daytime hours. The transmission of ballots by any type of modulation is prohibited.

Range 20 meters:

Range 17 meters:

Range 15 meters:

Range 12 meters:

Range 10 meters:

Allowable powers

Note:

• on the 2200 m range, all categories, with the exception of the fourth, are allowed an effective isotropically radiated power of 1 W,
• on the 160 m range, all categories, with the exception of the fourth, are allowed an average power of 10 W, and for categories 1 and 2 during participation in official radio sports competitions - 500 W.

+ Legend

All modes: CW, SSB and modes for which centers of activity are indicated, as well as AM. (When using AM, care must be taken not to interfere with stations on the adjacent channel)

Image transmission: Any method of image transmission - analog or digital - in which the signal has an appropriate bandwidth. For example, SSTV or FAX.

Narrowband types: All types having a signal bandwidth not exceeding 500 Hz. For example, CW, RTTY, PSK, etc.

Digital modes: Any digital modes that have the appropriate signal bandwidth. For example, RTTY, PSK, MT63, etc.

+ Notes

Frequencies in the plan are understood as signal frequencies and not as the frequency of the suppressed carrier. The entire signal bandwidth must fit within the allocated radio frequency band.

To prevent transmissions outside the allocated bands, the maximum frequency value on the tuning indicator indicating the frequency of the suppressed carrier, for USB mode(voice) should be 3 kHz below the top of the band in the bands 20 m to 10 m.

(*) minimum value frequency on the tuning indicator showing the frequency of the suppressed carrier, for LSB (voice) mode: 1843, 3603 and 7053 kHz

Morse code (CW) radio communications are permitted in all radio frequency bands with the exception of bands allocated exclusively for radio beacons.(IARU Recommendation DV05_C4_Rec_13)

Amplitude modulation (AM) can be used in telephone sections (LSB, USB) provided that it does not interfere with stations on adjacent channels.(NRRL Davos 05).

+ Use of sidebars

N Below 10 MHz the lower band (LSB) is used, above 10 MHz the upper band (USB) is used.

+ Competitions

Unless competitions involve DX traffic, competitions should not be held in the bands 3500-3510 kHz and 3775-3800 kHz.

During major international competitions, radio amateurs not participating in them are advised to use the WARC HF bands (30, 17 and 12 m).(DV05_C4_Rec_07)

Competitions must be limited to the 160, 80, 40, 20, 15 and 10m bands.60, 30, 17 and 12 m should not be used for competitions.(VIE16_C4_Rec_06)

+ Remote control of amateur radio stations - IARU clarification

National amateur radio organizations are advised to inform their members that CEPT Recommendation T/R 61-01 applies to radio operators using the call sign of their amateur radio station with the appropriate host country prefix only if the radio operator is physically located in the country stay. The above recommendation does not apply to remote control radio station. (IARU Sun City Conference Recommendation SC11_C4_REC_07)

Remote control refers to the radio operator's control of his amateur radio station through a terminal not physically connected to the radio station.

For remote control, the following conditions must be met:

Remote control must be authorized by the Communications Administration of the country in which the radio station is located, or the Communications Administration must not object to remote control of the radio station*.

1. Regardless of the location of the operator, the call sign of a radio station controlled remotely must be issued by the Communications Administration of the country in whose territory the radio station is located.

2. It should be noted that IARU Sun City Conference Recommendation SC11_C4_07 encourages national amateur radio organizations to inform their members that CEPT Recommendation T/R 61-01 applies to radio operators using their amateur radio station call sign with the appropriate country prefix stay, only if the radio operator is physically located in the territory of the host country. The above recommendation does not apply to remote work.

3. Any additional requirements regarding the participation of remotely controlled amateur radio stations in competitions and diploma programs are subject to regulation by the organizers of these competitions and diploma programs. (IARU Varna Conference Recommendation VA14_C4_REC_04)

* In a number of countries, including Russian Federation(see 126-FZ “On Communications”), the permissive principle of access to the radio frequency spectrum applies. In such countries, the absence of objections from the Communications Administration is not enough; its permission to use an amateur radio station in remote control mode is required. The conditions for using an amateur radio station in remote control mode on the territory of the Russian Federation are defined in paragraph. 2 clause 3.1. Rules for the use of radio frequencies

+ Radio frequencies allocated for amateur repeaters and radio beacons

Radio frequency bands of amateur repeaters: 29515-29595 kHz (reception), 29615-29700 kHz (transmission) with a reception and transmission frequency spacing of 100 kHz; 145-145.1875 MHz (reception), 145.6-145.7875 MHz (transmission), with a frequency separation of reception and transmission equal to 600 kHz; and on a secondary basis: 433.025-433.375 MHz (reception), 434.625-434.975 MHz (transmission), with a reception and transmission frequency spacing of 1600 kHz, 1291-1291.475 MHz (reception), 1297-1297.475 MHz (transmission) with a frequency separation of reception and transmission equal to 6000 kHz.

The maximum peak power of the repeater transmitter envelope should not exceed 100 W, emission class – F1D, F3E, D2D, D2W, D1D, D1E, D1W.

Amateur beacon frequency bands: 14099-14101 kHz, 21149-21151 kHz, 28199-28201 kHz, 144.4-144.49 MHz and on a secondary basis: 18109-18111 kHz, 24929-24931 kHz, 432.4-432 .49 MHz, 1296.8-1296.994 MHz.

The maximum peak power of the beacon transmitter envelope should not exceed 100 W, radiation class - A1A, J2A, A1B, J2B, A1D, J2D, D1W, D2W.

The frequencies of amateur repeaters and radio beacons are assigned by the Federal State Unitary Enterprise "GRChTs".

+ How to use tables Decisions of SCRF

Introduction

In the Russian Federation, the function of regulator of the distribution and use of the radio frequency spectrum is performed by the State Commission on Radio Frequencies (SCRF). SCRF is an interdepartmental body in which representatives of interested ministries and departments - both law enforcement agencies and civilians - take part. Traditionally, the commission is chaired by the Minister of Communications and Mass Communications of Russia. SCRF regulates, among other things, the procedure for using radio frequency bands allocated to amateur and amateur satellite services, defining the boundaries amateur bands, permitted powers and types of radiation, as well as imposing technical requirements for amateur radio stations.

In accordance with clause 4. Article 22 of the Federal Law of July 7, 2003 No. 126-FZ “On Communications” (hereinafter referred to as the Law on Communications), the use of the radio frequency spectrum in the Russian Federation is carried out in accordance with the principle of the permitting procedure for user access to the radio frequency spectrum. This means that the use of the radio frequency spectrum by amateur radio stations, not provided for by regulations in the field of communications, is prohibited.

Liability for violating the rules for the use of radio frequencies is provided for in Article 13.4 of the Code of Administrative Offenses and provides for a fine with possible confiscation of radio-electronic equipment. In addition to this measure, it is possible to cancel the call sign of the amateur radio station of the offender.

Regulation of the use of radio frequencies

The original international document is the Radio Regulations of the International Telecommunication Union (ITU RR). Article 5 of the Regulations contains a table of the distribution of radio frequencies by radio service for each of the three ITU regions. The frequency bands allocated to the amateur service are also indicated in this table. The Regulations are regularly reviewed at World Radiocommunication Conferences (WRCs). Conferences are held once every three years, and the next WRC will be held in 2019. The interests of the amateur radio community during the preparation and conduct of the WRC are represented by International Union Radio Amateurs (IARU), which is an associate member of ITU. In turn, the SRR, being a member of the IARU, also participates in preparations for the WRC. One of the most important stages preparation for the WRC is the coordination of the positions of the SRR and the Russian Communications Administration on issues of the WRC affecting the interests of the amateur service.

The national (domestic Russian) analogue of the ITU RR radio frequency distribution table is the Table of Radio Frequency Band Distribution between Radio Services of the Russian Federation (TRFR), approved by the Decree of the Government of the Russian Federation. Any allocation of frequency bands for their use by amateur radio stations in the Russian Federation is made on the basis of the corresponding entry in this table.

If a particular radio frequency band is allocated to the amateur service, then the procedure for its use is determined by the corresponding decision of the SCRF.

It should be noted that neither the frequency distribution table of the ITU RR nor the TPFR specifies the conditions for using frequency bands in detail. For example, radio frequency bands are not allocated by type of radiation, frequency bands for intercontinental DX communications, radio expeditions, as well as for use for other purposes of interest exclusively to radio amateurs. At the international level, the International Amateur Radio Union (IARU) regulates all these issues. Each ITU Region has a regional organization, the IARU. In the first Region, which includes the countries of Europe, Africa, and the former USSR, there is a regional organization of the first Region (IARU-R1), which publishes a frequency plan - a detailed table of radio frequency distribution. The frequency plan is adjusted once every three years at the IARU-R1 General Conference. The next conference will take place in 2017 in Germany. IARU-R1 recommends that all its members - national amateur radio organizations - when developing national regulations governing the use of radio frequencies allocated to the amateur service, be guided, if possible, by the IARU-R1 frequency plan, and in the part not regulated by national regulations, recommend that radio amateurs use the recommendations IARU-R1.

Why is the table of radio frequencies in the SCRF Decision not a reference book?

Since 2015, the radio frequency tables contained in the SCRF Decision contain only information about the basis for the use of a particular radio frequency band (primary or secondary), the maximum permissible signal bandwidth, as well as the maximum powers by category. The SCRF Decision does not impose any other requirements for the use of amateur radio stations. For most radio frequency bands, the “Modulation Types” column indicates “All Types.”

Is it true that we need to understand that all types of radio communications can be operated without exceeding the required signal bandwidth? Not at all. This only means that government agencies do not care how this radio frequency band will be used by radio amateurs, as long as the amateur radio stations using it do not exceed the power and bandwidth of the emitted signal indicated in the table. Failure to comply with these requirements will result in a fine. in accordance with Article 13.4 of the Code of Administrative Offenses (CAO). Radio amateurs agree with each other in more detail about the procedure for using radio frequencies.

The table of radio frequencies contained in the SCRF Decision cannot indicate, for example, radio frequency bands for working with DX. If they were specified, then the supervisory authorities would have to fine radio amateurs for conducting intracontinental radio communications at these frequencies. This is unacceptable for government agencies. And for radio amateurs too.

Therefore, the requirements for the use of radio frequency bands by government agencies have the minimum necessary restrictions. All other regulation is carried out at the level of the IARU and national amateur radio organizations. Failure to comply with IARU recommendations will result in public reprimand.

Frequency plan IARU-R1

The IARU-R1 frequency plan assumes “soft” regulation, ensuring the effective use of radio frequency bands allocated to the amateur service in different conditions with different “loading” of the bands with stations with one or another type of radiation: when holding mass events (competitions, “days of activity”), changing radio wave propagation conditions, etc.

The IARU-R1 frequency plan involves grouping modulation types according to the maximum radio signal bandwidth and allocating a specific frequency band for each group. The following values ​​are used as standard signal bandwidth values ​​in the HF range: 200 Hz, 500 Hz, 2700 Hz and 6000 Hz. The current table of radio frequencies in the SCRF Decision fully complies with this principle.

Our website contains tables of radio frequency bands allocated to radio amateurs and recommendations for their use. These recommendations are consistent with current frequency plan IARU-R1, they also take into account the requirements of a number of regulations governing the activities of the amateur service in the Russian Federation.

So, for example, in the radio frequency band 14125 - 14300 kHz, amateur radio stations on a primary basis are allowed to operate by types of radio communications with a frequency band not exceeding 2700 Hz, namely: telegraphy, OBP, AM, image transmission (SSTV). There are no separate frequency bands allocated for AM, but the note to the table states that AM can be used in the bands allocated to the UBP, provided that it does not interfere with users of adjacent radio frequency bands, and the use of amplitude modulation must be limited.

It follows from the table that low-power amateur radio stations should cluster near the frequency 14285 kHz, and operators of high-power stations should be especially careful near this frequency. Amateur radio stations using digital voice (DV) are recommended to cluster around the frequency 14130 kHz, stations using SSTV - around the frequency 14230 kHz.

In this case, it is theoretically possible to give a general SSTV call on the frequency 14195 kHz, traditionally used for working with large DXpeditions. The violator will not face any liability to government authorities, but this will be a manifestation of extreme disrespect for the amateur radio community. The sanction for the violator in this case will be condemnation of his actions by the amateur radio community.

It is important to understand the difference between center of activity and ringing frequency. If the radio amateur is sure that no radio station is operating with this type of radiation, then it is recommended to use the frequency indicated in the table as the center of activity for a general call. At the same time, the calling frequency must remain free: after a call and answer, a pair of radio stations must either end the radio connection or continue it on another frequency. The use of calling frequencies is regulated by Order of the Ministry of Telecom and Mass Communications dated July 26, 2012 No. 184.

Let's give another example. Figure 2 shows a fragment of the 7 MHz band table.

From the table it follows that in the frequency band 7050-7060 kHz you can use both OBP and even AM. After all, there is the entry “all types,” and we already know what it means. However, the use of OBP in bands primarily intended for digital communications may be very limited. Everyone is well aware that many stations that use digital modes of communication, allowing them to operate at levels below the noise level, cannot be detected by ear reception. They can only be seen on a computer monitor using a special computer program. Of course, a short telephone radio connection with a distant station in this area cannot be considered a violation of IARU-R1 recommendations, but Holding “round tables” and “skeds” in these frequency bands, and transmitting a general call in the case when the frequencies in the upper part of the range, intended specifically for OBP, are free, is an absolutely unacceptable practice. There are other frequency bands for this purpose.

Note 2 for the 7 MHz band reminds you that the frequency bands indicated in the table must contain the entire spectrum of frequencies emitted by the radio station. With single-sideband low sideband modulation adopted for operation in the 7 MHz range, the minimum reading on the transceiver scale indicating the frequency of the suppressed carrier should be 7053 kHz. In this case, the lower limit of the frequency spectrum will be exactly 7050 kHz.

The frequency plan was compiled on the basis of the decision of the SCRF of July 15, 2010 No. 10-07-01 “On the allocation of radio frequency bands for radio-electronic equipment of the amateur and amateur satellite services” as amended by the decision of October 16, 2015 No. 15-35 on amending decision of the SCRF dated July 15, 2010 No. 10-07-01 “On the allocation of radio frequency bands for radio-electronic equipment of the amateur and amateur satellite services” (as amended by decisions of the SCRF dated March 10, 2011 No. 11-11-03, dated July 22, 2014 No. 14-26-04) taking into account the results of the SCRF meeting dated July 4, 2017 (

Effective isotropic radiated power of the order of 100 W, distribution of modulation types in accordance with IARU-R1 recommendations. Work plan:

2. Allocation of radio frequency bands to amateur radio stations in the Russian Federation5351.5–5366.5 kHz.

Rationale: the agreed position of national amateur radio organizations - members of the IARU on the need to allocate frequency bands between 3.5 MHz and 7 MHz to the amateur service for the transmission of messages in emergency situations during the years of minimum solar activity, as well as in connection with the changes made by WRC-2015 (Geneva) ITU RR, which entered into force on January 1, 2017.

Planned conditions of use: effective isotropic radiated power - no more than 15 W, type of modulation - telegraph only, mass events with the exception of training of amateur radio stations for transmitting messages in conditions close to an emergency situation are prohibited. Obtaining a RICH is not required. Work plan:

3. Allocation of the radio frequency band 50000.0–54000.0 kHz (or part thereof) to radio frequency bands of the amateur service in the Russian Federation on a secondary basis.

Rationale: Currently, the radio frequency band 50000.0-54000.0 kHz is not allocated to the amateur service in Region 1. Amateur radio stations in Europe use the radio frequency band 50000.0-52000.0 kHz based on the private European Table of Radio Frequency Allocations and Uses in the band 8.3 kHz - 3000 GHz (ECA TABLE). It is necessary to initiate changes to all regulations governing the use of radio frequencies - from the ITU RR to the SCRF Decision.

Planned conditions of use: effective isotropic radiated power of the order of 100 W, distribution of modulation types in accordance with IARU-R1 recommendations. Use on a secondary basis, subject to obtaining an expert opinion on electromagnetic compatibility with existing and planned distribution zones, permission to use radio frequencies and radio frequency channels, and a certificate of registration of distribution zones.

Work plan:

4. Coordination with the Communications Administration of the removal of time restrictions on the operation of radio beacons. (2016)

Done: Order of the Ministry of Telecom and Mass Communications of the Russian Federation “On amendments to the Requirements for the use of the radio frequency spectrum by the amateur service and amateur satellite service in the Russian Federation, approved by order of the Ministry of Communications and Mass Communications of the Russian Federation dated July 26, 2012 No. 184” dated November 17, 2016 No. 572

5. Coordination with the Communications Administration of the conditions for recognition of belonging to the amateur service of radio electronic networks and the allocation of radio frequency bands to them.

6. Participation of the SRR representative in working group CEPT "Spectrum Management"