Rapid deployment antenna on CB (27.200). Antennas for CB radios Antenna for 27 MHz radio station

I want to tell you about my method of making a light basic CB antenna from a fiberglass fishing rod. In order to place the entire matching circuit inside the fishing rod, we take the most “compact” circuit from the point of view of the matching coil.
Pay attention to the capacitor C1, its operating voltage must be at least 500 volts, taking into account that we will not use the transmitter power anymore 10 Watt.

In principle, you can secure the fishing rod to the mast with simple nylon ties, but I propose a more reliable method. We weld together a strip of metal and a corner of arbitrary convenient sizes, as shown in the photo below.

A water pipe will be used as the base of the side extension, to which our corners will be welded. Subsequently, this pipe will be inserted into the mast and bolted there.

We assemble the coordination scheme using wall-mounted installation. We will use a thick copper stranded wire as a radiating element.

We fix the assembled structure inside the fishing rod in any available way. Having previously cut out a window in the base for adjusting the SWR. The fishing rod itself is attached to the stem using car clamps.

To obtain a wider operating band, you can attach a small capacitive load to the tip of the antenna.

We adjust the SWR at an average frequency of 27.200 MHz by compressing and stretching the turns of the coil.

After final adjustment of the antenna, you should seal the “tuning” window with electrical tape and fill it with glue; you should also fill the joints of the knees with glue.

The antenna installed at a low altitude showed good results when working over long distances.

CB radios are often used in the country and in the field. Moreover, sometimes a C-B radio station is purchased only to ensure communication with a dacha, a fishing spot or on a hiking trip. Since the physical dimensions of C-B antennas in the 27-MHz range are relatively small, then, as a rule, in the dacha and in the field conditions there are no problems with installing a full-size antenna.

The main criterion that must be taken into account in this case is the ease of installation of the antenna, and the purposes for which the antenna will be intended. Now let's move on to consider the practical designs of these antennas.

A simple country quarter-wave vertical CB antenna of the 27 MHz range. In my opinion, the optimal antenna that can be installed in a dacha is a quarter-wave vertical. This antenna has many advantages over other types.

It emits radio waves that are predominantly vertically polarized, which is optimal for communication with car and portable radio stations in the 27-MHz C-B range.

The vertical polarization radiation pattern of a vertical whip antenna is circular, so it will be able to provide radio communications in all directions, which is often required of it. For example, Provide radio communication with the city, with the highway along which the car approaches the dacha, with a fishing or hunting place.

Rice. 1 shows a diagram of a quarter-wave vertical antenna of the Si-Bi range. Let's take a closer look at the design of this antenna. It consists of a lambda/4 electrical length pin connected to the central core of the coaxial cable and four counterweights. The pin can be 5-40 mm in diameter, the exact length for several pin diameters is indicated in this figure.

To make it, it is convenient to use an aluminum or copper tube. For example, two ski poles that have reliable electrical contact with each other work well with copper water pipes, which have recently appeared on the market.

Fig.1. 27 MHz antenna design.

The counterweights can be positioned to the antenna pin at an angle of 90 to 140 degrees. Depending on the angle at which the counterweights are located to the antenna, the input impedance of the antenna depends.

A quarter-wave whip antenna, installed at a height of at least 0.3L relative to the ground surface and equipped with four quarter-wave counterweights, has an input impedance of about 20 ohms when the counterweights are located at an angle of 90 degrees to the antenna. The antenna resistance increases to 40 Ohms when the counterweights are located at an angle of 120 degrees to the antenna, and to 50 Ohms when the counterweights are located at an angle of 135 degrees to the antenna (see L.1).

Of course, it is preferable to use counterweights located at an angle of 135 degrees to the antenna pin, in which case the antenna has an input impedance of 50 ohms, which optimally matches the coaxial cable with a characteristic impedance of 50 ohms.

Increasing the antenna installation height has little effect on the nature of the antenna input impedance. Reducing the antenna installation height causes an increase in input impedance.

This occurs due to the absorption of the reactive field existing near the antenna by the real earth. As a result, the transmitter energy is spent on heating the earth and is not used for radio communications. Low installation of the vertical antenna should be avoided; otherwise, in order to maintain operational efficiency, the number of antenna counterweights should be increased to several dozen (L.2).

At the end of the coaxial cable, it is advisable to install a high-frequency choke (also called a blocking choke), which will prevent high-frequency current from flowing into the outer sheath of the cable. This may happen if, for some reason, the resistance of the outer sheath of the coaxial cable is comparable to the resistance of the counterweights.

In this case, the outer sheath of the cable will serve as the radiating part of the antenna, which will lead to an increase in the level of interference when the antenna operates for transmission and loss of high-frequency energy in objects surrounding the coaxial cable. The simplest design of a blocking choke is 10-30 ferrite rings tightly placed on the end of a coaxial cable; the permeability of the rings does not matter.

Instead of ferrite rings, you can use ferrite tubes, which are installed on the cords of computer monitors. When installing ferrite rings on a coaxial cable, the resistance of the area where the ferrite rings are installed for high-frequency currents increases significantly, as a result of which high-frequency current from the coaxial cable will flow into the antenna elements rather than into the outer shell of the coaxial cable.

Rice. 2 shows a graph of the input impedance of the antenna shown in Fig. 1. Fig. 3 shows the SWR of this antenna in relation to a coaxial cable with a characteristic impedance of 50 Ohms, and Fig. 4 shows the vertical polarization radiation pattern of this antenna.

The MMANA program shows the antenna radiation pattern in the horizontal plane as a section of the volumetric diagram with X-Y planes along the angle of maximum radiation. In the vertical plane, the antenna's radiation pattern is a cross-section by the X-Z plane of its volumetric radiation pattern.

In Fig. 1, which shows a vertical antenna, shows the location of these section planes. In the calculations, it was assumed that this antenna is located at a height of 3 meters above the real ground (conductivity is 5 mS/m, dielectric constant e = 13). These graphs were calculated using the MMANA program (see L.2).

In all cases of calculation, it was assumed that the diameter of the pin is 20 mm, the diameter of the counterweights is 4 mm, and the antenna is made of copper.

Table 1 shows the length of the pole of a vertical antenna mounted 3 meters above the real ground, and equipped with four counterweights 270 cm long, located at an angle of 135 degrees to the antenna pole, at which it resonates at a frequency of 27 MHz.

Please note that changing the height of the antenna, the number of counterweights, and their angle of inclination leads to a change in the resonant frequency of the antenna. The resonant frequency of the antenna will decrease if you use a pin or counterweights in plastic insulation (see L.1).

The antenna can be tuned to the resonant frequency by lengthening/shortening the antenna pin (some methods for lengthening/shortening the antenna pin are given in L.2), as well as antenna counterweights. Adjustment of the antenna input impedance can be done by changing the angle of inclination of the counterweights relative to the antenna pin.

As can be seen from Fig. 3, with SWR in a coaxial cable with a characteristic impedance of 50 Ohms<1,5 антенна со штырем диаметром 20 мм обеспечивает достаточно широкую полосу пропускания, равную 1700-кГц. Это позволяет работать антенне в трех сетках каналов Си - Би диапазона, и подходить менее строго к ее настройке.

A further increase in the diameter of the pin leads to an expansion of the antenna's bandwidth, and a decrease in the diameter of the pin leads to a narrowing of the antenna's bandwidth.

Fig.4. Directional pattern of a homemade 27 MHz antenna in vertical polarization.

Rice. Figure 5 shows the dependence of the bandwidth of the antenna described above (a rod with a length corresponding to Table 1, 4 counterweights with a diameter of 4 mm located at an angle of 135 degrees to the rod, an installation height above the real ground of 3 meters) for an SWR value in a coaxial cable equal to 1.5: 1 and 2:1.

As can be seen from this figure, even a “thin” antenna with a 5 mm thick vibrator will provide acceptable operation on the 27 MHz C-B band, especially if you focus on the SWR in the coaxial cable of the antenna equal to 2:1, and this is precisely the value The SWR is quite consistent with 99% of commercial CB transceivers.

It is quite possible to manufacture a vertical antenna with a pin consisting of vibrators of different thicknesses, for example, from a ski pole with a diameter of 16 mm and a length of 1.5 meters and a piece of wire from a power transmission line with a thickness of 4-6 mm and an approximate length of 1.2 meters. The MMANA program allows you to calculate the parameters of such so-called “tapered” antennas.

The English word (in this case, it would be more accurate to say the American) “tap” can be translated here as “part of an antenna of a different diameter.” In the case of such a combined antenna, it is necessary to use a design that ensures reliable electrical contact between sections. For example, in this case, a vibrator of a smaller diameter is riveted into a vibrator of a larger diameter, a vibrator of a smaller diameter is tightly screwed to a vibrator of a larger diameter, or a transition insert is used between vibrators of different diameters.

To install a vertical whip antenna, you can use natural or artificial elevations. For example, you can use a dry tree or a roof ridge as a mast.

Fig.6. Installation of a homemade 27 MHz antenna on the roof ridge.

When installing the antenna on the roof ridge, make sure that there are no objects under the antenna that absorb high-frequency energy. Installation of the antenna on the ridge of the roof of the cottage is shown in Fig. 6.

To attach the antenna pin as a homemade support insulator, you can use a strong, dry wooden stick, preferably oak, which must first be boiled in paraffin. This will give this surrogate support insulator electrical strength, insensitivity to moisture and protection from rotting. The antenna is attached to a wooden stick with two long screws; in extreme cases, it is simply screwed with a thick wire.

Instead of a wooden stick, you can successfully use pieces of plastic water pipes or a plastic ski pole. Instead of these surrogate support insulators, it is quite possible to use commercial support insulators, or support insulators used for installing VHF intercom antennas. Support insulators from old decommissioned VHF antennas can be purchased inexpensively on the radio market.

Pay serious attention to the installation height of the antenna. The minimum acceptable height for the C-B range can be considered 0.25 * lambda, or 2.75 meters. In this case, the height is measured from the base of the antenna.

As the height of the antenna decreases, the ground begins to absorb high-frequency energy that is created around the counterweights and under the base of the antenna when the antenna is operating. In practice, this will be expressed in a drop in antenna gain and in a decrease in radiation at small angles to the horizon, which is exactly what is required for both low-level (local) and long-distance communications on the CB. The antenna counterweights will no longer have resonance on the 27 MHz band, and the antenna will need to be tuned only by changing the length of the vibrator.

It is possible to eliminate the effect of loss of antenna gain and increase radiation at lower angles to the horizon by increasing the number of counterweights, and in order for the antenna to work sufficiently efficiently, the number of its counterweights can be in the dozens (more information about the number of counterweights of an antenna located on the ground can be read in L.2). However, in my opinion, on the 27 MHz band it is easier to use an elevated whip antenna with 2-4 counterweights than to install dozens of non-resonant counterweights around a antenna standing on the ground.

To power the quarter-wave vertical antenna shown in Fig. 1, a coaxial cable with a characteristic impedance of 50 ohms is required. It is desirable that the electrical length of this cable be a multiple of half the CB wavelength of the 27 MHz range; this will immediately eliminate many problems that arise during setup and operation of the antenna.

As mentioned earlier, the input impedance of a quarter-wave vertical antenna depends on many factors, and in practice it can be in the range of 30-70 ohms for an amateur radio vertical quarter-wave antenna installed on a roof ridge. Using a half-wave section of coaxial cable to power the antenna will allow you to “deliver” the input impedance of the antenna without unnecessary transformation directly to the output stage of the transceiver, which, in general, will somewhat increase the efficiency of this antenna-feeder system.

For a cable with polyethylene insulation, the length of the half-wave segment will be 3.63 meters, and for a cable with fluoroplastic insulation, 4.4 meters. It is necessary to pay serious attention to protecting the opening of the coaxial cable from atmospheric influences. The easiest protection can be achieved using fast-hardening automotive epoxy putty.

More details about vertical antennas can be read in L.Z and L.4.

A whip antenna installed in a rural area high above the ground, even a small one designed for the 27-MHz CB band, needs protection from atmospheric electricity. Otherwise, the transceiver connected to this antenna may be damaged and the operator may receive electric shock. Some methods of protecting antennas from atmospheric electricity are described in L.2 and L.Z.

Grigorov I.N. RK2005, 2.

Literature:

1. Grigorov I.N. Antennas. Urban structures. - M.: IP RadioSoft, 2003.
2. Grigorov I.N. Antennas. Configuration and coordination. - M.: IP RadioSoft, 2002.
3. Grigorov I.N. Practical antenna designs. -M..DMK, 2000.
4. The ARRL Antenna Book. 20-Edinion: published by ARRL, USA, 2003.

Parabolic antenna KNA27-1700/2700 is designed to organize a wireless data transmission channel in the frequency range 1700-2700 MHz and amplify the mobile signal of GSM 1800, 3G (UMTS 2100), 4G (LTE 1800, LTE 2600), YOTA, Wi-Fi 2400 standards in places with poor reception.

• Provides reliable long-range reception of 3G, LTE and WiFi Internet.
• Suitable for working with all operators (MTS, Megafon, Tele2, Rostelecom, Beeline, Yota, etc.).

Contents of delivery

• Parabolic mesh reflector - 1 pc.
• Irradiator 1700-2700 MHz - 1 pc.
• Fastening kit - 1 set
• Operating manual - 1 copy.
• Packaging - 1 pc.

The antenna structure consists of:

• MIMO irradiator;
• Wire parabolic direct-focus reflector.
• Irradiator mounts and reflector mounts.

The reflector is painted with polymer powder paint. All unpainted parts are galvanized zinc. This guarantees long-term operational stability and trouble-free operation.

Using this antenna, you can ensure reliable communication with the base station at a distance of up to 25 km in line-of-sight conditions.

Due to the fact that the parabolic antenna - 2 x 27 dB has low wind resistance because made of resistance-welded steel wire and does not have a continuous surface, like a satellite dish mirror, such an antenna can be safely installed on a high mast, which is almost impossible to do with a satellite dish mirror.

Selecting an antenna installation location

1. It is advisable to install the antenna in the line of sight of the base station antennas of 2G/3G/4G/Wi-Fi operators.
2. On the path from the antenna to the base station there should be no nearby high obstacles (buildings, mountains, hills, forests, etc.) that interfere with the propagation of the signal. Therefore, install the antenna as high as possible.
3. Large objects (tall trees, roofs of houses) located closer than 1.5 meters from the antenna can cause reflection of radio waves and deteriorate the quality of communication. If you have any excess cable left, use it to raise the antenna up off the ground. Antenna installation options are shown in Figure 1, where options 1 and 2 are the correct installation. Options 3 and 4 with incorrect installation (a tree and the wall of the house interfere with the signal propagation).
4. The distance from the antenna installation site to the modem location should be as short as possible, since the use of a long connecting cable will lead to partial attenuation of the signal and deterioration in communication quality.

1. Install the bracket (5) onto the reflector base (4) and secure it with three short bolts. Install brackets (6) with clamps (7) onto the bracket (5).
2. Turn the parabolic reflector (4) over, install the two tabs (3) on the base and secure them with short bolts.
3. Pass the cables from the illuminator (1) through the illuminator stand (2), and firmly insert the illuminator (1) into the illuminator stand (2) until it stops.
4. Then, having threaded the cables through the tabs (3) and the central hole in the base of the reflector (4), install the irradiator stand (2) assembled with the irradiator (1) into the tabs (3) according to diagram 1.
5. Depending on the frequency range of the base station with which your antenna is configured to work, install the antenna feed stand (2) according to the diagrams below.
6. Secure the irradiator stand (2) to the legs (3) with a long bolt. Tighten all antenna connections according to diagrams 2, 3 or 4.

Attention! An antenna that supports MIMO technology must be connected to equipment (modem, router, etc.) with two antenna inputs.

Attention! Directional parabolic antennas have a very narrow radiation pattern (2-4 degrees) and require precise pointing to the operator's base station.

1. Before installing the antenna, check the polarization in which the signal is emitted by your operator's base station. As a rule, this is vertical polarization. To change the polarization, move the bracket (5) on the base of the reflector (4) by 90° (Diagram 1). For antennas with MIMO technology, the vertically polarized cable is marked with a colored mark. This feature allows you to change the polarization without moving the antenna when the antenna operates with 3G/4G modems.
2. Install the antenna assembly on a grounded mast (8), as shown in Diagram 1, lightly securing it with clamps and allowing the antenna to be repositioned.
3. Point the antenna at the base station. Having found the antenna position at which the data transfer rate or signal level is maximum, fix the antenna to the mast by tightening the clamp nuts.
4. Lay the cable assemblies from the antenna to your equipment (3G/4G modem, router, repeater, etc.), avoiding sharp bends.

The warranty period is 24 months from the date of purchase.

Due to the constant improvement of the design and technical characteristics, the manufacturer reserves the right to make changes to the design and completeness of this product.

*This product is shipped only after 100% payment or (if you do not pick up the order at the Russian Post office, prepayment is non-refundable).

What is the prepayment for?

Prepayment is a necessary measure, since the size of the antenna in the package is 95x95x30 cm, weight is from 6 kg (depending on the components selected in the options on the website), delivery is quite expensive. If you do not pick up the order, it is returned and we pay the delivery cost twice (from us to you and back), which ends up being quite expensive. In order not to take into account possible returns and not to increase the cost of the antenna, it was decided to prepay the order in the amount of 800 rubles. As a result, you get the minimum cost of the antenna, and we are confident that you will receive your order.

You can make an advance payment by clicking on the link - after payment you will receive a payment receipt by email with the name of the payment and the recipient's organization. If you decide to cancel your order, your prepayment will be refunded in full before it is shipped.

On the pages of this catalog you will find antennas for car CB radios, suitable for different situations and radios, located in different price categories and having different characteristics from each other.

To make the right choice, read product descriptions. If you have any additional questions, our consulting engineer will be happy to answer them.

Here are just a couple of examples of what differences you can get that are beneficial to you (take different manufacturers):

• Alan 9 Plus. This antenna is a cut-in type (a small hole is drilled in the housing for installation). Its operating frequencies are 25-30 MHz, it has 200 channels, a gain of 4 dB and a maximum power of 300 W. The length of the pin is 155 cm, the pin is made of stainless steel;
• MegaJet ML-145 MAG-160. This antenna is already attached to a magnetic base. Its frequency range is 26.9-27.5 MHz, the number of channels for operation has been increased - 120, but the height of the pin has been reduced - 142 cm. The antenna has the same power (300 W), although its peak power can reach 900 W;
• Optim CB-2001. This antenna is intended, rather, for vans and trucks: its length is 2 meters, it has an unshakable mortise mount, and the maximum input power is 2000 W.

You can find out additional characteristics of the antennas by following the appropriate links to the product pages. Please note that the catalog contains antennas for discontinued or obsolete radios.

We will be happy to answer any questions about antennas for civilian radios. Call!

Pokhodnayamobile antenna "STERKH"

for CB-band (27 MHz)

Idea

After our vigorous experiments with portable and basic antennas, the task arose to create something in between in terms of efficiency. A portable 40 cm pin has a good performance limit of up to 7-8 km. Carrying a second Owl with you through the forest is hardly convenient, and deploying it in a desert area without a mast is generally unrealistic. In addition, not all “dummies” can handle an oar to solder a control system correctly.

I wanted to make the antenna as simple as possible, from a couple of wires, and I calculated the Zabredun dipole, from which I intended to dance. However, it turned out to be worse than thought: narrowband, with SWR on the verge of good, and negative gain. Most likely, the dipole was considered in MMANA , which does not know how to work with low-mounted antennas and overestimates dbi . In addition, the radiation goes mainly upward!...

The same garbage as the first version of “Owl”. If you calculate the antenna taking into account the thinnest insulation, the SWR will become completely sour... That is, this dipole, of course, is better than a standard rod, but only due to the height of the suspension and the length of the blades. Take a look at the results:

Z =78.417 + j 64.474 SWR (50+ j 0)= 2.92

Max Gain : -1.02 dBi at azimuth : 222 deg

Max Gain: -0.12 dBi at elevation 79 deg

To be fair: on the test, the dipole showed an SWR of about 2. But this design is still not suitable for us, like everyone elsecommon “forest” analogues of radio amateurs - dipoles, beams, inverted V, classic GP and so on. – they are either outrageously long, or “shoot” upward, or require at least one suspension point, and quite a high one at that.Making a mini-analogue of the “Owl” is also a bad idea, the matching device will kill the entire efficiency of the antenna. And in general, the “owl” place is at the base! Place it and smoke bamboo. A group or person leaving the camp will want to take something more convenient with them in the sweep (RU3DKW considered the option of a plumb bob with a capacitive load, but did not get to the point of specific modeling, although we may still be thinking about this option).

In short, the new antenna must be portable enough to be worn, and at the same time not much inferior in efficiency to the Sova, and most importantly, it must be deployed by one person on any terrain and cover at least 15 km with a “good” rating.

Sergei turned out to be very busy, so I had to think through the geometry, material, and study the necessary programs myself; after which I modeled and calculated a structure vaguely reminiscent of a paper crane. So, our “birds” have arrived in the regiment!...

Theory

USTERKHA rigid vibrator made of duralumin tubes, bent at the top at a right angle, and two counterweights:

The antenna has a simple geometry, no matching device, no soldering, and no feeder. The most difficult thing here is to fuse the lower tube and BNC -mom. The tubes must fit tightly into each other, be even at the joints and smooth. The most complex element is a pipe bent 90 degrees.

The antenna has V -polarization and good bandwidth (~1460 kHz at SWR<=1,5 и ~2890 <=2.0). СТЕРХ рассчитывался условно на середине СиБи диапазона (27,605 мгц), с реальной землей средней плешивости.

The antenna turned out to be directional and has a gain** ~1.5 Dbi at a small angle to the horizon, which is very good for such a small and mundane structure. The direction of STERKH radiation is concentrated from the center of the open corner of the counterweights. You must use counterbalances to take the correspondent “in pincers.” Considering that the angle is quite wide, it can be conditionally directed towards the side of the world where the interlocutor is located.

In the classic case, the vertical part of the vibrator is built as 210 cm, and the “beak” = 40 cm. In this case, the counterweights = 282-286 cm, and their lower ends should be ~30-40 cm above the ground. The length of the “beak” can vary from 24 to 40 cm, without affecting the matching, but the total length of the antenna must remain 250 cm.

As you can see, the petal of the diagram is well pressed to the horizon, which cannot but please the eye. C with any insulated wire, the antenna has an SWR of no more than 1.2 (in all programs). Considering that the STERKH counterweights are insulated, the first dimensions had to be adjusted taking into account the radii of the “skins,” but I was satisfied with the results:

Vibrator – made from duralumin tubes with a diameter 6 mm (wall thickness 0.6) and is divided into segments. A larger number of segments is dictated solely by the portability of the antenna.

The tubes fit into each other according to the principle of tent poles; inside the vibrator there is a 2 mm elastic band, which is sold in any fishing store. The lowest tube is rigidly fixed in the wiring box, into which it is screwed BNC - connector, or in another way,

The lowest point of the vibrator should be located 160-170 cm from the ground (theoretically, this is the height of the connector of the walkie-talkie, which an adult holds in his hand during a conversation). The position of the "beak" does not matter.

When using a tube with a cross-section 10 mm the gain above the horizon will reach ~2 decibels. When using hardware, the bandwidth increases, but the matching deteriorates (the dimensions must be adjusted) and decreases dbi (almost twice). In addition, the vibrator becomes heavier, so you should not use stainless steel.

Counterweights - you can use any insulated copper wire 0.5-1.5 mm in diameter. They must be attached with a clamp or soldered to the ground of the antenna connector.

When purchasing a silicone audio cable, you should pay attention to one whose “skin” thickness is no greater than the diameter of the core, and, preferably, round in shape. The thick “peel” can suppress up to half a decibel, which we already have in short supply...

The counterweights must be positioned exactly 90 degrees relative to each other. A slight narrowing of the angle is allowed, but not widening! The bottom end of each counterweight must be in ~ 30 cm from the ground, and the top one - 160-170 cm. The ideal angle of plumb lines relative to the ground is 45 degrees.

Stretching the plumb lines lies entirely with the operator, since the top attachment point is the walkie-talkie, which he holds in his hand. Plumb lines actively participate in the diagram and should not sag or be incorrectly positioned in space.

In order to properly stretch the counterweights, first spread them at right angles on the ground, stick in the pegs, and then lift the radio and pull it. At the end of each counterweight it is necessary to make a rope guy, and at its end - a loop for a peg.

Naturally, both counterweights must be made of the same wires and be the same length. It is advisable to avoid breaks and soldering - for STERKh these are radiating elements.

Construction

Nikolai from FMK*** made two sets of pipes in a few hours, fortunately they have everything: pipes, machines and extensive experience in working with aluminum. Unfortunately, the 6 mm pipe is too thin to work with bushings, and it had to be bored out to fit the “neighbor”, so several unplanned thickenings appeared on the vibrator at the joints.

An example of a camping kit:

Vertical part: 10+40+40+40+40+ 40 cm + 6 cm bent pipe = 216 cm

Horizontal part: 34 cm of bent pipe (“beak”).

216+34= 250 cm total length. When making pipes, remember that each joint “eats” 2 cm! Therefore, each tube should be made 2 cm longer.

There are different ways to attach a vibrator to a walkie-talkie. I decided to attach it to the “legs” of old 50-ohm “telescopes” that were lying around the house without use. This is not difficult to do, since the copper wire from the coil is already soldered in, all that remains is to cut off the required piece, clean it with a file and screw it onto the tube. A small groove was machined into the aluminum for this purpose:

Don't forget about the problem of contact between different metals. If you simply solder or wind a copper wire from the connector core onto an aluminum pipe (as I did for the test), after a while we can have a war of antagonists in the form of oxide, and, as a result, non-contact. Therefore, it is better to connect them through an iron “intermediary” in the form of a self-tapping screw or something else.

And now the first STERKH is ready!

STERKH folded next to the Berkut

This is what STERKH looks like on “Alan”:

I designed two antennas, with different thicknesses of counterweights (in silicone), one of which was sent to the Pushkinsky district for a joint test.

Let's consider “my” option with counterweights with a copper core cross-section 0,75 mm and length 282 cm each. Vibrator height = 216 cm, beak length = 34 cm. Length of counterweight ropes = 95 cm .

Measurements on the street with radio stations "Berkut-803A" and "601m2T" showed that the calculation of partsturned out to be correct:

Real SWR indicators at frequencies 28 805-705: B601 = 1.1, at B803 = 1.2. You can't drink away mastery!… J The design hit the spot.

The height of the suspension of the lower ends of the plumb lines during the measurement was about 30 cm, and the height of the antenna suspension (in fact, eye level) ranged from 160 to 170 cm from the ground, while the SWR remained stable.

Tests

A strong snowstorm during testing has already become a good tradition. But the more angry you are in training, the easier it is for the birds in battle!… J

Chil and Seryoga crawled out into their yard in Pravda, and I, as usual, crawled onto the Mytishchi field, about a hundred meters from the house, I turned the “Owl” around in the snowdrifts and prepared the STERKH. The initial plan was this: if we don’t break the initial 20 km between two STERKHs, then the guys get into the car and shorten the distance until the signal appears.

However, the very first connection between the Siberian Cranes showed an almost perfect connection = 5.8 –5.9! Moreover, “Owl” was heard a little “worse”. Either the polarizations of the fry did not match, or the gain of the new antenna beat even the five-meter vibrator of a competitor, whose gain is close to zero, by the way.

Inspired by the results, the men drove another 8 km, and then another 2. The road wanders a lot into the forest, so there is enough vegetation. In total, the maximum distance for that day was exactly 30 km (point at GPS between Balabanovo and Khlopenevo). Not enough, but I got stiff in the wind and the test was stopped. In terms of signal strength, STERKH has a power reserve for a longer distance (minimum 40 km).

The connection was mainly 5.7-5.8-5.9. Sometimes (after 20 km) it dropped to 4.8. Very strong interference in my area. For this reason, Pravda always heard me a point better than I heard them. However, the signal is good and clear, intelligibility is almost 100%.

I worked at 6 and 5 watts. At 28 km, the guys connected the B601m2 on batteries (2 watts), and I heard them normally, although the signal became worse (4.7) - I had to listen through the interference. Total: it is clear that after 20 km, radios with 4 or more watts rule, but communication with a low-power one is also possible. The problem was mainly in the strong QRM , if it weren’t for the interference, the two-watt connection, even at long distances, would be 4.9, at least. We can conclude that in places with clear air, the antenna will work well with any power. And the weak signals of STERKH, according to Chila, “pressure”, so a distant dispatcher somewhere on the Kola will not interfere with conversations. Despite the terrible on-air noise, STERKH allowed us to conduct a test on only two channels, which once again confirms the thesis: happiness is not in the number of channels, but in the efficiency of the antenna. J

Since I was unable to take a photograph of myself, I am attaching a drawing of a fictitious man. Here's how it all looks schematically (the antenna is pointed at the correspondent - at you):

Results

STERkh belongs to the class of “mobile” antennas I invented - something between a basic and portable antenna for hiking communications. Gain in the direction of the correspondent ~ 1.5 decibels. Great job at the intersection. The operating range of STERKH is determined by the landscape and in clear air conditions it can, I think, reach 50 km.

What do we have compared to Owl-2?

Pros:

1. No complex matching device

2. No need for suspension points: trees, masts, sticks, etc.

3. Availability of real gain at low vibrator height

4. No need for local adjustments: SWR will not go beyond 1.5 anywhere

Minuses:

1. Antenna directivity. Still, you need to turn her “facing” the correspondent, at least conditionally

2. Manufacturing of tubes (needs machines, etc.***)

3. Tubes are more susceptible to breakage than soft wire

Despite the fact that the tubes are more difficult to make, a hard vibrator distinguishes the antenna from its “soft” counterparts - it can be used on flat terrain and without having to run around looking for trees, which, by the way, like to bend the diagram and spoil the matching. Now any landscape: desert, steppe, tundra, bald foothills - everything is in our hands! J

The thickening at the joints did not affect the efficiency of the antenna, so you can use this vibrator manufacturing scheme, but it is necessary to seal the joints - this is a clear disadvantage for the test version.

Rubber , stretched inside the tubes, ensures almost lightning-fast assembly of the vibrator. Stretching two counterweights, I think, will also not cause any particular difficulties. STERH easily fits into a deep jacket pocket. Damaged counterweights, if something happens, can be easily replaced with new ones - the wires are simply attached with a clamp to the connector leg. A broken segment can also be healed - when ordering tubes, ask for a spare piece of 5 centimeters, 1 mm wider (or narrower) than the main diameter, for joining “fractures” if you plan to use the antenna harshly.

What else to say?

Everything worked on the first shot! … J The idea and implementation were a success, even somewhat exceeding my modest expectations. A portable antenna for quick deployment, weighing less than a stick of butter, which reaches more than 30 km - a tourist’s dream! In fact, this is a day's travel between groups, so communication can be ensured without setting up a hospital with those who are lagging behind, those who have gone into radial camp, etc. Of course, it is better to make two such antennas at once for a group.

Considering that the antenna does not have flimsy radio components, you can connect a 50-ohm transceiver up to 100 watts to it, and then the range will increase even more. The antenna gain will also increase if, for example, you work from a hill, cliff, etc. The SWR will be within 1.2 at any altitude. However, the optimal rise above the ground will be about 7-12 meters - the gain above the horizon will be more than 3 dB!

It should be noted that two and a half meters is the maximum height of an aluminum vibrator with a diameter of 6 mm, “standing” directly on the radio; as the length increases, its stable position in the connector will become problematic.

In general, both the guys and I were very pleased with the STERKH, and we decided, when the roads melted, to test it (and at the same time the Sova-2) to its maximum range, so, as always, to be continued... J

Several observations during STERKH tests:
Firstly, the “supreflex” antenna (40 cm) hears STERKH well at a distance of 20 km even in conditions of interference, but with a counterweight. The guys did not use the standard one, which got stuck somewhere, but an analogue of the STERKH counterweight - two wires of 286 cm each, with a cross-section of 0.75. At the same time, their long ends simply lay on the snow. I even heard snippets of transmission from the “superflex”, but the interference blocked everything out. When the counterweights were removed, the radio with the “superflex” stopped hearing me, if I understood “Pravda” correctly. So plumb lines help a short pin, as I have already seen more than once.
Secondly, I came to a very interesting conclusion regarding interference. We made contact twice from the same points, at the same time, but on different days. On a cloudy, snowy day, the connection was much better than on a completely clear and sunny day. After chatting with my colleagues, I decided that close to the centers of civilization on a clear day the level of interference increases by 2-3 times. Maybe low clouds and snow flakes “press down” (prevent) weakened interference arriving from the outside, and only “our own” ones remain. And on a clear day, everything you care about flies into the area - distant radio noise, electrical interference, etc. This may be stupid, but the result is obvious... :)
Along the way, I discovered some good AA batteries that I can recommend for walkie-talkies: Panasonic Xtreme Power. Since January I’ve been looking forward to them (B803A) and at least I don’t care. Although, perhaps, the economizer built into the new Berkuts also plays a role.

Adviсe

1. Try not to be between the counterweights (inside the corner) when transferring. Stand to the side or behind

2. Do not use the antenna during a thunderstorm or when there is a real danger of lightning

3. Do not touch handsets during transmission

4. Do not make the segments longer than 40 cm - otherwise the antenna will lose its portability.

Many thanks to Chil and Sergey (RU3DKW) for participating in the tests! J And also to the inhabitants of the forum QRZ , for advice on mastering the programs.

Data on the second STERKH: vibrator 255 cm, “beak” 25 cm, feeder 97 cm, length of one counterweight 268 cm, length of one guy 100 cm. SWR: 1.5 SWR (27,805), 1.2 MFJ (27,805), 1.0 MFJ (27,505)

An alternative version of the antenna is in the form of a bayda angle. ru. We are ready to make tubes for antennas according to orders. You can refer to me and make an exact copy of the tested kit. When reprinting material, a link to the article is required