Building a HF antenna - a guide for beginner radio amateurs. Multi-band HF antenna “Asymmetrical dipole Antenna for 40 meters

Antennas. antennas 2 antennas 3 antennas 4

Antenna LW

I consider it necessary to publish a description of the LW-82 m antenna (in common parlance - a rope). The fact is that this antenna, at minimal cost - no feeder, no need to go to the roof (it is enough to live on the 2nd floor and have a suspension point at a distance of more than 80 m from your house) has very good parameters and allows you to start working on the most interesting ranges 160, 80, 40 m.

A description of such an antenna is also in the book “HF-VHF Antennas” by the authors Benkovsky, Lipinsky, fig. 5-20. A very important note: the tuner for this antenna must have good radio grounding, and these are only quarter-wave counterweights for each band, in the worst case, the heating system of your home. The diagram of the simplest tuner for such an antenna is presented below:

Coil L1 is wound on a frame with a diameter of 40 mm with a wire with a diameter of 1-1.25 mm and contains 50 turns with a winding length of 70 mm. The coil has taps from the 13th turn (range 40 m), counting from the right, and from the 23rd turn, counting from the right (range 80 m); when taps are not used, the entire coil operates on the 160 m range. Naturally, to the right of the 13th turn, taps can be made for the ranges of 20, 15, 10 m. The taps are indicated approximately according to V.A. Suvorov (UA4NM). For your tuner, naturally, the turns will have to be selected individually according to the SWR meter turned on before the tuner or, in the simplest case, according to the maximum air noise on a given range or according to the neon light bulb for the transmission.

Vladimir Kazakov

Efficient balcony antenna at 145 MHz

I needed a universal antenna with good characteristics for working in different conditions on 145 MHz, for example from home, when it is not possible to install the antenna on the roof, from a car, in a parking lot and, of course, while camping. After going through different designs, I settled on a two-element directional antenna. Despite the simplicity (I would even say banality) of the design, it has many advantages, and the ease of manufacture allows us to call it a “weekend design.”

In the photographs you can see how this antenna is installed on my balcony. The design turned out to be strong; it is not afraid of rain and strong winds. Before that, on the balcony, I had several different antennas: a zigzag without a reflector, the branded A-100 and A-200, but this particular design proved its effectiveness, so I removed the other antennas as unnecessary. When installed on the roof, 2 el. at 145 MHz they do not play with a 3x5/8 collinear antenna, I tested the A-1000 5 meters long. When testing, at a distance of 50 km, the signal from the A-1000 and the 2-element antenna was the same. This is how it should be because the A-1000 has a real gain of approximately 4 dB, and the one described here is 2x el. antenna 4.8db. It always outperformed any car antennas of the following types: 1/4, 1/2, 5/8, 6/8, 2x5/8. If two such antennas are phased together, they confidently outperform the A-1000. Check it out for yourself and see for yourself.

Let's look at the design, it is very simple (although it may not be beautiful in appearance, I did it in 40 minutes) and consists of a reflector 1002 mm long and a split vibrator 972 mm long (10 mm cable gap). The distance between the reflector and the active element is approximately 204 - 210mm. The elements themselves are made of 4mm insulated wire. If your wire is different, you need to adjust the dimensions. Cover the soldering areas with damp rubber to prevent moisture from entering. SWR from 144 to 146 MHz, approximately 1.0 - 1.1, measurements were carried out with the SWR-121 device.

The antenna input impedance is 12.5 ohms, for optimal matching with the 50 ohm cable, I used a transformer made from two pieces of fifty-ohm cable. They should have the same length, 37 - 44 cm (choose more precisely when setting up) each. Both pieces of cable must be pressed against each other along their entire length. That's all. I recommend this antenna to everyone, instead of pins, zigzags, branded collinear antennas and other crap that clearly have too much gain! If you compare it with two squares, then with approximately equal gain, for two squares you will need 4 meters of wire, but for this antenna only two. For two squares, you will need a stronger stick because they will be noticeably heavier. The difference in gain is 0.3 dB, which is completely insignificant for real QSOs, but the suppression on the sides and back is 2. The antennas are much smaller and this is also a plus, because we need a circular radiation pattern.

High gain option

Many people ask how to further increase the gain of the described antenna and at the same time maintain a wide lobe. When adding elements, not only will the gain increase, but the petal will also narrow greatly. Everything is very simple, you need to phase several antennas of the same type. The picture shows how to do this. The easiest way is to phase 2 or 4 antennas; you only need to space them vertically, because horizontal separation will also narrow the main lobe. Since the described antenna has weak directivity, you will get an antenna with high gain and an almost circular pattern. Another important advantage of connecting several antennas of the same type is improving the quality of reception of mobile stations on the move. Yes, yes, mobile stations with this simple design will be received much better than with various branded pins 5 - 7 meters long (type A-1000, 3x5/8, etc.). I also recommend installing such antennas in cities that are surrounded on all sides by mountains. Now the numerous “reflections” that appear in such places will work for you. In such conditions, 2 x 2 will actually outperform “solid” multi-element antennas. The actual gain of a two-antenna design is approximately 7.3 dB. But keep in mind that it will receive better than a single antenna with a real gain of 8-10 dB. Four phased antennas will have a gain of 12.3 dB, and the directivity will be almost circular! No single antenna can compete with it!

Hiking option

After some time, a collapsible version of the antenna was made for hiking and expeditions. Tests in the field have confirmed its good efficiency; it is not inferior to collinear antennas 3 - 5 meters long (2x5/8 or 3x5/8) at a range of up to 50 km and outperforms them at distances of 90 km or more. The photo shows the camping version of the antenna, disassembled. It takes 30 seconds to assemble the antenna. A plastic water pipe with a length of 510 mm and a diameter of 21 mm is used as a boom. The dimensions of the elements were slightly adjusted because a different wire was used. For such a small antenna, there will always be a place in your backpack, and at high altitudes, in the mountains, you won’t have to make excessive efforts to hold it (those who were at 4000 and above know what I’m talking about). The cable and transformer are located inside a plastic pipe, this protects them from accidental breaks and moisture. The antenna can be repaired right on the go; bent elements just need to be straightened by hand, etc.

50 ohm antenna option

At the request of the “lazy people” who did not want to make a transformer, I calculated an antenna with a resistance of 50 ohms for direct connection to the cable going to the radio station. The appearance remains the same. The cable is connected to the active element directly; to improve symmetry, I recommend making one turn around the ferrite ring, as close as possible to the soldering point. The gain of this antenna option is slightly less and is approximately 4.3 dbd. The dimensions are given for wire with a diameter of 4 mm; if you have a different material, you need to adjust the dimensions. The distance between the reflector and the active element must be selected more accurately, within the range of 415 - 440mm, until the minimum SWR is obtained.

Simple tri-band antenna

The antenna is operational in the ranges of 40, 20, and 10 meters. A transformer on a HF-50 ferrite ring with a cross section of 2.0 cm is used as a matching element. The number of turns of its primary winding is 15, the secondary winding is 30, the wire is PEV-2 with a diameter of 1 mm.

When using a different section, you must reselect the number of turns using the diagram shown in the figure.

As a result of the selection, it is necessary to obtain the minimum SWR in the range of 10 m. The antenna manufactured by the author has the SWR:

1.1 - on the 40 m range;

1.3 - on the 20 m range;

1.8 - on the 10 m range.

V.Kononovich (UY5VI). "Radio" No. 5/1971

20 meter indoor antenna

L1=L2=37 turns on a frame with a diameter of 25 mm and a length of 60 mm of wire with a diameter of 0.5 mm. J1 connector in a small plastic case.

Compact antenna tuner

The circuit works perfectly and matches the antenna from 80 to 10. Surprisingly, I didn’t find any losses in the tuner when testing at 50 Ohm load. Either bypassing 100 W, or through a tuned tuner 100 W, on all ranges from 80 to 10.... The coil, although compact, is cold... The resonance is quite sharp, and this tuner can be perfectly used as a preselector .

In general, everything works great with SW-2011, because... there is no DFT in it and the tuner plays the role of a preselector, which has a very beneficial effect on the quality of reception. I don’t recommend using “Amidon” rings, as many in the “West” do in these tuners - they are both expensive and overheat (introduce losses). Simply not sense. A regular reel on a plastic frame is much more

better. From experience - the diameter of the frame for power up to 100 W does not matter much - I checked from 50mm to 13mm in the last version. There is no difference. The main thing is to maintain the total inductance of the coil at about 6 μH, and proportionally recalculate the taps (or select them specifically for your antenna)

The critical components are KPIs. If the gap is small, it “stitches” them, because the voltage across them reaches hundreds of volts. But nevertheless, even with small-sized capacitors, I achieved normal operation (without breakdowns at 3.5 and 7 MHz as I had at first) by introducing the SW2 toggle switch, which switches the antenna output tap on the 3.5 and 7 MHz ranges to most of the turns coils. This achieves a reduction in the voltage on the capacitors when tuning the tuner.

Shortened vertical antenna

The vertical antenna described below, designed for operation on the 80 m band, has a total height of slightly more than 6 m.

The basis of the antenna design is pipe 2 with a diameter of 100 mm and a length of 6 m, made of dielectric (plastic). Inside the pipe, to give it mechanical strength, there is a wooden block 3 with spacers 4, which are in contact with the inner surface of the pipe. The antenna is installed on base 7.

Approximately 40 m of copper single-core wire 5 with a diameter of 2 mm, having moisture-resistant insulation, is wound onto the pipe. The winding pitch is selected so that the entire wire is evenly wound around the pipe. The upper end of the wire is soldered to a brass disk 1 with a diameter of 250 mm, and the lower end is connected through a variable capacitor 6 to the central core of the coaxial cable 8. This capacitor should have a maximum capacitance of about 150 pF and in terms of quality (rated voltage, etc.) not must yield to the capacitor used in the resonant circuit of the transmitter output stage.

Like any vertical antenna, this antenna requires a good grounding or counterweight 9. Tuning and matching the antenna with the feeder is done by changing the capacitance of the capacitor 6, and, if necessary, changing the length of the wire wound on the pipe.

The quality factor of such an antenna is higher and, therefore, its bandwidth is narrower than that of a conventional quarter-wave vibrator.

Built by a radio amateur WA0WHE a similar antenna with a counterweight of four wires has an SWR of up to 2 in a bandwidth of about 80...100 kHz. The antenna is powered via a coaxial cable with a characteristic impedance of 50 Ohms.

Ground Plane for 5 kV bands

The proposed antenna option can be classified as a “weekend design”, especially for those shortwave operators who already have a “GROUND PLANE” station for the 20-meter range at their station. As can be seen from the figure, in the center of the antenna there is a duralumin pipe with a diameter of 25...35 mm, which serves as a supporting mast and a vertical quarter-wave element for a range of 20 m.

At a distance of 402 cm from the base of the pipe, a fiberglass plate measuring 60x530x5 mm is fixed with two M4 screws. The ends of four-wire (3 mm in diameter) vertical elements are attached to it, the electrical length of which corresponds to a quarter of the wavelength for the middle of the 17, 15, 12 and 10 m ranges.

A fiberglass plate measuring 180x530x5 mm is screwed to the lower end of the pipe with two M4 screws. An aluminum plate measuring 15x300x2 mm with five holes with a diameter of 4.5 mm is placed under the lower edge of the pipe, through which five M4 screws are passed, which are used to fasten the wire elements and the pipe. To ensure better electrical contact, a piece of copper wire is inserted between the pipe mounting screws and any nearby wire element.

At a distance of 50 mm from the aluminum plate, another one of the same size is fixed, but with 6-12 holes, which are used for attaching radial counterweights (six for each range).

The antenna is fed via a coaxial cable with a characteristic impedance of 50 Ohms.

The dimensions of all elements and counterweights are indicated in the table. The distance between vertical elements is 100 mm. Due to the windage of the antenna, it is fixed with two tiers of nylon guys. The first tier is fixed at a distance of 2 m from the base of the pipe, the second - at a distance of 4.1 m.

If you have a “GROUND PLANE” on 40 m, then using the described principle you can create a 7-band antenna.

Indoor broadband...

Wideband indoor active loop antenna S. van Roogie increases the efficiency of receiving radio stations of all HF bands (3-30 MHz) by approximately 3-5 times compared to a telescopic one. Due to the fact that loop antennas are sensitive to the magnetic component of the electromagnetic field, electrical interference created by various household appliances is significantly weakened.

Interference-resistant shortwave receiving antennas

(Review of materials from the magazine "QST", 1988)

Many fans of long-distance radio reception on short waves, as well as short-wave radio operators who are interested in conducting DX radio communications, especially in the low-frequency HF bands, and who have at their disposal only a GP antenna with vertical polarization, often face in practice the problem of ensuring noise-free radio reception. “Moreover, in the conditions of large industrial cities, it is most significant. Signals from DX radio stations are often quite small, while the field strength of industrial, atmospheric, etc. interference at the receiving point can be quite high. In this case, it is necessary to solve the following problems :

1 - weakening of this interference at the input of the radio control unit with the least attenuation of the useful signal;

2 - ensuring the possibility of receiving radio signals in the entire shortwave range, i.e. broadband antenna-feeder device;

3 - the problem of providing sufficient area to place the antenna away from sources of additional interference. Significant reduction in the level of atmospheric, industrial, etc. interference can be achieved by using special receiving antennas with low noise levels. In the literature they are called "Low-Noise Receiving antennas". Some types of such antennas have already been described in (1, 2, 3). This review summarizes some interesting experimental results in this area obtained by foreign radio amateurs.

EXPERIMENTAL SHORT-WAVE RECEIVING ANTENNAS WITH LOW NOISE LEVEL

When starting to engage in long-range radio reception on KB, you must first of all think about a good noise-proof antenna, this is the key to success. As already noted, the task of an anti-interference antenna device is to reduce interference to the greatest possible degree with the least possible attenuation of the useful signal. For obvious reasons, it is impossible to talk about the amplification of the useful signal by the receiving antenna, especially in the low-frequency HF bands, because such an antenna will take up quite a lot of space and have a pronounced directivity. In some cases, to amplify the received signal, it is advisable to use pre-amplifiers between the radio control unit and the antenna, providing them with manual gain control (1). This also applies to antennas, which will be discussed below. These antennas are a modification of the Beverage antenna, the classic version of which is shown in Fig. 1a. This antenna is widely used in professional HF radio communications and has some anti-interference properties. W 1FB experimented with a modification of the Beverage antenna and obtained interesting practical results, which he published in the April issue of QST magazine. Some shortwave operators considered them an April Fool's joke, while others, on the contrary, supplemented these results with their practical experience. In Fig. 1b. shows an antenna with the exotic name "Snake" (which means "snake"). It consists of a long piece of coaxial cable placed on the ground or in the grass. The far end of the cable is loaded with a non-induction resistor with a resistance equal to the characteristic impedance of the cable. This resistor must be placed in an insulating box and sealed to prevent moisture from entering the coaxial cable.

Since making practically such an antenna for the low-frequency KB bands is quite expensive, due to the high price of the cable, W 1FB proposed making the antenna from a two-wire ribbon cable or wire for a telephone or radio broadcast line.

The characteristic impedance of such lines is different and can

be determined from tables, as well as experimentally. When determining the length of this antenna, it is necessary, as in the first case, to take into account the shortening factor. The antenna in the form of a two-wire loaded line for the 160-meter range should have a length of about 110 meters. It is quite difficult to place such an antenna above the ground, so W 1FB laid the cable around the perimeter of its site. In this case, the basic properties of the antenna are preserved if there are no foreign objects nearby that could affect the antenna’s performance and be a source of additional noise. This could be vertical antenna grounding systems, various metal pipes, fences, etc. When an antenna is placed around the perimeter of the site, its directional properties are weakened and it begins to receive signals from different directions. In this design, it is important to accurately determine the characteristic impedance of the two-wire line used. This is necessary for the correct calculation of the matching broadband transformer and load resistor, the resistance of which must be equal to the characteristic impedance of the line used. The transformation ratio is selected depending on the coaxial cable used. It is equal to:

R H /R K -(N/n) 2

Where: R H - load resistor resistance, Ohm;

R K - characteristic impedance of the coaxial cable, OM;

N is the number of turns of the transformer winding on the antenna side;

N is the number of turns on the receiver side (power line).

In Fig. 1 year the antenna proposed by W 1HXU is shown. It is located above the ground and is made of ribbon cable with a characteristic impedance of 300 Ohms. To configure it, a variable capacitor with a capacity of up to 1000 pF is used. The capacitor is adjusted to the highest level of the received signal. Figure 1 d shows an antenna of the “Snake” type, made of a coaxial cable having a length of just over 30 meters, which is laid in the ground. The far end of the cable has a connection between the central core and the braid. At the "receiving end" the braid is not connected to anything. This antenna was tested by W 1HXU and obtained good results on the 30, 40 and 80 m bands.

CONCLUSION

When designing antennas with a low level of interference, it should be taken into account that they weaken the useful signal quite strongly, so the use of antennas made of coaxial cable is justified only in cases of very high levels

industrial interference at the receiving point. As already noted, in these cases

It is advisable to use additional amplifiers. Antennas made of a two-wire symmetrical line in a tape dielectric have less attenuation of the useful signal and give more reliable results. It should also be noted that the use of all antennas described above is possible only if there is

in the input control panel, designed for connecting antennas with a wave impedance of 50 or 75 Ohms. If there is no such input, then you need to use an additional communication coil, which can be wound on top of the coil of the RPU input circuit for the HF band on which you expect to use these antennas. The number of turns of the communication coil is from 1/5 to 1/3 of the number of turns of the HF band loop coil. The connection diagram for the additional coil is shown in Fig. 2.

Multi-band antenna with switchable radiation pattern

The problem of creating a sufficiently efficient multi-band antenna in limited space, requiring relatively low costs, worries many radio amateurs. I would like to offer another version of the “poor radio amateur” antenna that satisfies these requirements. It is a system of slopers with pattern switching, operating on the bands 3.5, 7, 14, 21, 28 MHz. It is based on the operating principle of the RA6AA and UA4PA antennas. In my version (Fig. 1), 5 beams go from the top of a 15-meter mast at an angle of about 30-40° to the ground, which simultaneously serve as the upper tier of guys. There may be more beams, but preferably at least 5. The total length of each beam is 21 m, about 80 cm is subtracted from it for the outlet to the relay box and about 15 cm for fastening the insulator in the lower part of the beam. Thus, the actual length of each beam is about 20 meters. The antenna is powered by a coaxial cable with a characteristic impedance of 75 Ohms, approximately 39.5 meters long. The cable length is critical - together with the length of the beams, it must be 1 wavelength on the 80 meter range. All beams are initially connected to the cable braid. The choice of the required direction is made directly at the workplace, while the corresponding relay connects the beam of the selected direction to the central core of the cable. As with most directional antennas, the suppression of the side lobes is more pronounced than the suppression of the rear lobes, and averages 2-3 points, less often - 1 point. A comparison was made with the RB5QT log periodic antenna suspended at a height of about 9 m above the ground in an east-west direction. At 7 MHz, slopers won in these directions by 1-2 points.

Design. The mast is telescopic, from R-140, stands on the ground without additional grounding, without dielectric inserts. The beams are made from field telephone cable P-275 (2 wires of 8 steel and 7 copper conductors each), well soldered using acid. 75 ohm coaxial cable. It is possible to use a cable with any characteristic impedance, as well as an open two-wire line with a resistance of 300-600 Ohms. The relay is used type TKE52 with a supply voltage of about 27 V with parallel contacts, but others can be used, depending on the power of the transmitter. A separate four-wire cable is used to power the relay. This circuit (Fig. 2) allows you to power 6 relays; due to local conditions, I have 5. To switch voltages, P2K buttons with dependent fixation are used. The dimensions of the antenna and power line can be changed in any direction, using the formula L2 = (84.8-L1 )*K, where L1 is the length of one arm, L2 is the length of the supply line; K is the shortening coefficient (for a cable - 0.66, for a two-wire line - 0.98). If the resulting line length is not enough, you must substitute 127.2 in the formula instead of 84.8. For a shortened version, you can substitute 42.4 m into the formula, but in this case the antenna will only operate at frequencies above 7 MHz.

Setup. The antenna practically does not need adjustment, the main thing is to comply with the specified dimensions of the beams and cable. When carrying out measurements with an RF bridge, it turned out that the antenna resonates within the amateur bands, and its input impedance is within 30,400 Ohms (see table), so it is advisable to use a matching device. I used the UA4PA recommended parallel circuit with taps. In the 160 m range, this antenna does not work - the resonant frequency of 1750 kHz was chosen so that in other ranges the resonance would be within the range.

FREQUENCY	Zin, Ohm
1750	20
3510	270
3600	150
7020	360
7100	400
10110	50
14100	260
14250	200
14350	180
18000	50
18120	50
21150	190
21300	180
21450	160
24940	59
25150	50
28050	160
28200	200
28500	130
29000	65
29600	30

Size: px

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Transcript

1 Building a HF Antenna A manual for beginner radio amateurs Introduction. An antenna is a radio device that converts the energy of radio waves into an electrical signal and vice versa. Antennas vary in type, purpose, frequency range, radiation pattern, etc. In this article we will look at the construction of the most common amateur radio antennas.!!important!! 1. The best amplifier is an antenna! Remember this phrase like a multiplication table!! A good, tuned antenna will allow you to listen and make radio communications with very weak and distant stations. A bad antenna will negate all your efforts to purchase or build a receiver/transceiver. 2. Building good antennas involves working at heights (masts, roofs). Therefore, exercise all safety measures and caution. 3. It is strictly forbidden to approach or touch the antenna or descent cables during a thunderstorm!! Now let's look at the antennas themselves. Let's start with the simplest and up to the highest quality. Slant Beam Antenna This is a piece of copper wire that is attached at one end to a tree, lamppost, or the roof of a neighboring house, and the other end is connected to the receiver/transceiver. Advantages: - simplicity of design. Disadvantages: - weak gain, highly susceptible to city noise, requires coordination with the transceiver/receiver. Manufacturing. Any type of wire is copper. Single-core, multi-core, you can even use a computer “twisted pair” cable. Any thickness, but “so as not to tear” from its weight, tension and wind. On average, the cross-section is sq.mm. Length. If only for the receiver, then any, from 15 to 40m. If for a transceiver, then the length should be approximately L/2 of the range on which you will work. For example, for the 80m range = L/2 = 40m. But, always take with a margin of 5-7m.

2 The antenna wire cannot be tied directly. It is necessary to install several insulators at the end of the antenna web. Ideal “nut-type” insulators: What these insulators are needed for should be clear from their very name. They isolate the antenna sheet electrically from the tree, pole and other structures where you will mount the antenna. If nut insulators are not found, you can make homemade ones from any durable dielectric material: plastic, textolite, plexiglass, PVC tubes, etc. Wood and derivatives (chipboard, fiberboard, etc.) cannot be used. There should be 3-4 insulators at the ends of the antenna, with a distance of 30-50cm from each other. Typical Slant Beam Antenna Installation Schemes

3 The input impedance of the receiver or transceiver is usually standard and equal to 50 Ohms. The Slant Beam antenna has significantly higher resistance, so you can’t just connect it to a receiver or transceiver. You need to connect through a matching device. Here is the diagram: Matching the antenna is very simple. 1. Place the biscuit switch in the extreme right position so that all turns of the coil are turned on. 2. Turn capacitors C1 and C2, achieving the loudest possible reception of stations or broadcast noise. 3. If it doesn’t work, switch the biscuit switch further and repeat the setup procedure. When the antenna is matched, you will hear a sharp increase in the volume of stations or air noise. Conclusion. This antenna is good for beginner radio amateurs who mostly just listen to the airwaves. Yes, it is very noisy, picks up household and city noise, etc. But, as they say, for lack of anything better, it will do. We also want to warn you right away. If you have a low-power transceiver, 1-5W, then with such an antenna you will be very poorly heard, or you will not be heard at all. Keep this in mind when building or purchasing a low-power transceiver. P.s. Mounting height of the Slant Beam antenna. For such an antenna there is a simple rule: the lower, the worse. And vice versa. If, for example, you string it over a fence, at a height of 3 m, you will only be able to hear local radio amateurs, and that’s not a fact. Therefore, raise the antenna as high as possible. An ideal solution between the roofs of multi-storey and high-rise buildings. The real solution is not lower than meters from ground level.

4 Antenna “Dipole” Introduction. We immediately pay attention to the little things, but they are important)), the emphasis in the word on the letter I, dipole. This is already a more serious antenna than an inclined beam. A dipole is two wires in the center of which the coaxial cable of reduction is connected to the transceiver. The length of the dipole is L/2. That is, for a section of 80m range, the length is 40m. Or 20m of wire in each arm of the dipole. For more accurate calculations, use formulas. 1. Exact formula: Dipole length = 468/F x, where F is the frequency in MHz of the middle of the range for which you are making the dipole. Example for the 80m range: - frequency 3.65 MHz. 468/3.65 x = meters. Please note this is the total length of the dipole. This means that each shoulder will be 2 times smaller, that is, a meter. The error when constructing dipole arms should be kept to a minimum, no more than 2-3 cm. The most important thing is that the shoulders are the same length. 2. On the Internet there are also online “calculators” for calculating dipoles and other antennas: etc. Dipole manufacturing. To make the antenna, we need copper wire in the same way as for the inclined beam. Section 2.5-6 sq. mm. You can use insulated wire; in low-frequency ranges, PVC insulation introduces insignificant losses. Dipole placement is similar to slant beam placement. But here the height of the suspension plays a more noticeable role. A low-hanging dipole will not work! For normal operation, the height of the dipole suspension must be at least L/4. That is, for the 80m range it should be no lower than 17-20m. If you do not have such a height nearby, then the dipole can be made on the mast so that it takes the shape of an inverted letter V. Here are pictures of how to hang the dipole correctly:

5 The last option for installing a dipole is called “Inverted-V”, that is, the shape of an inverted letter V. The center of the dipole must be at least L/4, that is, for the 80m range 20m. But, in real conditions, it is allowed to hang the center of the dipole on small masts, trees, 11-17 m high. A dipole at such a height will work, however, noticeably worse. The dipole is connected with a coaxial cable with a characteristic impedance of 50 Ohms. This is either a domestic cable of the RK-50 series, or an imported RG series and similar ones. The length of the cable does not play a special role, but the longer it is, the greater the signal attenuation will be in it. It’s the same with cable thickness; the thinner, the more signal attenuation. The normal cable thickness for a dipole (measured by the outer diameter) is 7-10mm.

6 Options for connecting the cable to the dipole. At this point we ask you to be very careful, because now you will learn the many years of experience of the “experienced” ;). The modern world is a world of household radio interference - powerful, fat, whistling, chirping, growling, pulsating and other bad things. The reason for the interference is our modern life: - TVs, computers, LED and energy-saving lamps, microwave ovens, air conditioners, Wi-Fi routers, computer networks, washing machines, etc. and so on. This whole set of “life” creates hellish noise on the radio, which sometimes makes receiving amateur radio stations completely impossible. Therefore, it is no longer possible to connect a dipole as before in Soviet times. Now more details. 1. Standard cable connection to the dipole. The dipole arms are screwed onto any durable dielectric plate. The central core of the cable is soldered to one arm, the cable braid to the second arm. You cannot screw the cable, only solder it. This connection was standard in Soviet times, when there was no domestic interference on the air. Now such a connection can be used only in one case: - you live in a country house or in the forest, you have a very high receiver sensitivity and high transmitter power (100W and above). But this rarely happens, so we move on to modern connection options.

7 2. Connection option for the city, when using a powerful transceiver transmitter. The connection of the cable to the dipole itself is the same, but before soldering we put ferrite rings on the cable, the more the better. The main thing is that these rings are as close as possible to the place where the cable is soldered, almost right next to each other. Here, according to this principle: It is advisable to use rings with a magnetic permeability of 1000NM. But, any that you find and that will fit tightly on your cable will do. You can use rings from TVs and monitors: After installing the rings on the cable, put heat shrink tubing on them and crimp them with a hairdryer so that they fit tightly. If there are no such technologies, then in our native style, wrap it tightly with electrical tape;). This method will slightly reduce the noise level during reception. For example, if your noise level was 8 points, it will become 7. Not much, of course, but better than nothing. The essence of this method is ferrite rings that reduce the reception of interference by the cable itself.

8 3. Connection option for the city, as well as for low-power transmitters. The best option. There are two connection methods. 1. Take a ferrite ring of the required diameter, with a permeability of 1000NM, wrap it with electrical tape (so as not to damage the cable), and thread 6-8 turns of cable through it. Then we solder the cable to the dipole in the usual way. We have a transformer. It also needs to be connected as close as possible to the dipole soldering points. 2. If you don't have a large ferrite ring to push the thick, stiff coaxial cable through, then you'll have to solder it. We take a smaller ring and wrap 7-9 turns of wire with a diameter of 2-4mm around it. You need to wind two wires at once, and also wrap the ring with electrical tape so as not to damage the wire. How to connect is shown in the figure: That is, we solder the arms of the dipole to the two upper wires of the transformer, and the central core and cable braid to the two lower ones.

9 Connecting the cable to the dipole in this way kills two birds with one stone: 1. reduces the noise level that the cable itself receives. 2. matches a symmetrical dipole with an asymmetrical cable. And this, in turn, increases the chance that you, with a weak transmitter (1-5W), will be heard. Conclusion. The Dipole antenna is a good antenna, it already has a small radiation pattern and receives and amplifies better than the Slant Beam antenna. A dipole, especially with the 3rd connection option, is an ideal solution if you go into the forests and hikes to work on the air from there. And at the same time you have a low-power transceiver with an output power of 1-5W. Also, a dipole is an ideal solution for the city and for beginner radio amateurs, because it's easy to string between roofs, doesn't contain any expensive parts, and doesn't require any adjustments as long as you get the length right in the first place. Delta or Triangle Antenna Introduction. The Triangle is the best low-frequency HF antenna that can be built in an urban environment. This antenna is a triangular frame made of copper wire, stretched between the roofs of 3 houses; a reduction cable is connected to the gap at any corner.

10 The antenna is a closed circuit, so household noise is canceled out in phase. The noise level of the Delta is several times lower than that of the Dipole. Also, Delta has more gain than Dipole. To work at long-distance stations (over 2000 km), one of the antenna corners must be raised, or vice versa, lowered. That is, so that the plane of the triangle is at an angle to the horizontal. Illustrative examples (approximately): Oblique beam noise level 9 points. Dipole with simple connection noise level 8 points. Dipole with transformer connection noise level 6.5 points. Triangle noise level 3-4 points. Here is a video comparing a dipole with a triangle (delta). Did you watch it?) Compare?) If you don’t understand what the reception noise level is, then you can check it right now. Listen to online receivers and compare the noise level on them. It is shown here: This is the S-meter scale, which shows the level of the received signal. When there is no signal, it shows the noise level. Remember how radio amateurs say “I hear you 5:9”? 5 is the signal quality, and 9 is the volume level according to the S-meter. Now, listen to the receivers and compare the noise levels: As you can see, on one receiver the noise level is S5, on the second S8. The difference is very noticeable to the ear. And the whole reason is in the antennas. Do you understand now how important it is to make a good, high-quality antenna?

11 Making a triangle. The triangle is made from copper wire. Stretches between the roofs of neighboring houses. If the triangle is strictly horizontal to the ground, then it will radiate upward. With this arrangement, only short-range communications up to 2000 km will be possible. To make long-distance connections possible, the plane of the triangle must be rotated at an angle to the horizon. The length of the delta wire is calculated by the formula: L (m) = 304.8/F (MHz) Or you can use the online calculator on the website: For the 80m range, the length of the triangle should be 83.42m, or 27.8m each side. The height of the suspension is not lower than 15m. Ideally 25-35m. Connecting the cable to the triangle. You can’t just connect a 50-ohm cable to a triangle, because the characteristic impedance of the triangle is Ohm. It must be matched with the cable. For these purposes, matching transformers are created. They are also called baluns. We need a 1:4 balun. It is possible to make a balun in a high-quality and correct manner only with the help of instruments that measure the parameters of the antenna. Therefore, we will not provide a description of its manufacture. For beginner radio amateurs, the only option is to either buy a balun, or go to your neighbors who are more experienced radio amateurs, for example, to a local radio circle and ask for their help. For a sample, what kind of balun is needed: Conclusion. In conclusion, we once again draw your attention to the fact that the Antenna is the most important element for a radio amateur. The best!! Having built a good antenna, you will be heard loudly, even if you have a homemade transceiver with 1-5W output power. And vice versa: - you can buy a Japanese transceiver for 2 thousand American rubles, but the antenna was made poorly, in the end no one will hear you). Therefore, measure 1000 times and make a good antenna once. Take your time, don’t rush, calculate, think through and measure everything. Let us give you some advice: if you don’t know the distance between your houses, take a look at Yandex maps, they have a ruler function + the maps were updated in 2015. You can calculate the antenna using them.

12 Important points about where and how antennas should not be placed. Some people place HF antennas in the low frequency bands on masts, right on the roofs of residential buildings. This is absolutely impossible to do and here's why: 1. The dimensions of the antennas are always calculated taking into account the height to the ground. If you place it on the roof, then the height will be calculated not from the ground, but from the roof. Therefore, if you have an 18-story building, and you placed the antenna on the roof, consider that you placed it at a height of 2-3 m from the ground. It won't work for you. 2. A residential building is a hellish swarm of household clutter. An antenna installed on the roof will catch them all, and even ferrite rings and transformation will not help!! Therefore, if you are making wire antennas for low-frequency HF bands (80m, 40m), then: - place them as far as possible from the walls of houses. - hang antennas between roofs, not above roofs. - raise them as high as possible. - Always use ferrite rings or matching baluns and transformers. That's all, good luck in building a good and low-noise antenna! 73!

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EH-40m on the roof of a house

"EH-antenna 40m" is installed on the edge of the flat roof of a 5 (five) storey residential building, instead of the antennas for the 20m and 15m bands that were originally installed. The time spent on installation was 40 minutes, taking into account the fact that I had to get down from the roof three times to control the resonance frequency in the desired part of the range.

At the resonance frequency, the SWR in the antenna feed line was equal to 1.08, exactly the same as during tuning and testing on the balcony.

Based on the analysis of trips to RDA: RA-08 and RA-27 (where imported cable was used) and the successful installation of antennas on the roof (RK50-4-11 cable is used) for various bands, an important conclusion was made:

It is necessary to use high-quality coaxial cable type RK50-4-11, and not imported cables of dubious quality! The cable length must be equal to half the wavelength, taking into account the cable shortening factor!

INTERESTING QSO (from my point of view).

December 9, 2012 While looking through the range, I recorded a call sign from Venezuela - YV4OW, but seeing that this call sign was already in my equipment log, I wanted to pass by, because... I had a QSO with him on this band, but using the FD-8 antenna. I decided to call him and he answered my call the first time, although at the same moment many stations from Europe called him! And this is with an antenna length of 70 cm and an installation height of 3 meters from the roof plane.

YV4OW - distance 9,863 km

confirmation in the form of eQSL from YV4OW

3B9/OH1LEG - distance 8,555 km

On the evening of January 2, 2013 worked on a general call on the range. Correspondents rarely approached, because Basically, my call sign has been in hardware magazines for a long time and I’m simply not interesting to them (repeats on various bands do not count towards diplomas and in my opinion this is a drawback of the EPC club conditions). A little later, going to the Display Reception Reports website, I saw (see screenshot below) that my reliable signal was received in Australia: VK7KT op. Graham loc: QE28TT. I already had a QSO with this correspondent, maybe that’s why he didn’t call me? The distance was 14,563 km using an antenna 70 cm long and an installed transceiver output power of 50 W!

On the morning of April 13, 2013, an unplanned small experiment was carried out to establish radio communications with various types of antennas with COLOMBIA - radio station HK3JJH.

Scanning the range, I found a working general call station HK3JJH. At this moment, the FD8 antenna was connected to the transceiver, which was stretched between the houses. For me it was a new station with COLOMBIA and naturally, without hesitation, I called him on FD8. Pedro (HK3JJH) didn’t even ask who called him. I decided to call again - to no avail. Having connected the EH antenna on 40m, I call Pedro (HK3JJH) again. He answered me right away and we had the usual QSO.

The idea of using fishing rods for more than just single verticals has been around for a long time. Based on them, you can make good directional systems for low frequency bands during field trips. Such a system must be switchable and portable. Limitations in weight and trouble-free installation made the project a “not easy” task, but the “fishing line” of thought allowed us to relax somewhat... The most convenient of the low-frequency ranges - 40m - was taken as a patient for experiments in nature.

The choice was made on the developments of colleagues, regarding the phasing of 4 verticals, the so-called. "4 SQUARE", which were described by TK5EP and VE3KF. All that was left was to buy 4 fishing rods 10m long. Besides the fact that they were incredibly difficult to find, it also turned out to be an expensive pleasure.

The length of the found fishing rods when folded is 1m55cm (the chair was placed for scale). The electrical tape is wound at a distance of 64 cm, counting from the bottom edge (more on this later). When unfolded, the height of the fishing rod is 9.6m - just right!!

A good test site could be made during RDAC2010, which was proposed by UA9CNV. He agreed without optimism, but the argument that “it’s all the same and you’ll have to do something” quickly swayed him in the right direction, especially since his existing non-optimal 40m field antenna in the form of parallel two highly elongated rhombuses standing on the ground It hasn’t inspired confidence in me for several years now, for various reasons :)

So, the hybrid Collins coupler on two Micrometals T157-2 rings was taken as a basis. The device diagram is presented below (taken from TK5EP, but some things have been corrected):

Transformers T1 and T2 are made on T157-2 rings. Winding is carried out with bifilar stranded wire D=0.8mm in insulation. It is advisable to make the characteristic impedance of such a line with a characteristic impedance close to 50 Ohms. You can check the prepared line by measuring the capacitance of the open line and the inductance of the closed line and substituting the values in the formula:

Where:
Z - line impedance, Ohm
L - inductance of the short-circuited line at the end, H
C - open line capacity, F

Each ring contains 7 turns, evenly distributed around the entire perimeter of the ring. 1 turn is if the wire is passed through the ring 1 time. The initially calculated inductance is 1.13 µH.

Capacitors must withstand the supplied power, and also, if possible, have a good TKE NP0, in order to avoid damage to the device during temperature changes, which can be from -50 to +50 degrees. The simplest solution is to use K15-5 capacitors, but they have a completely indecent TKE. Even capacitors with TKE H20 did not allow us to have a stable system. Although the system’s broadband is quite large, we must strive to overcome the situation. Each capacitor I have is designed like this: a mica capacitor with a positive TKE is soldered in parallel to K15u-1 - it has a negative TKE. The total TKE of such a battery is almost zero! As a last resort, place several K15-5 in parallel at a voltage of 3 kV (up to 1 kW), but the capacitance should be rated at a temperature of -10 degrees, then you can largely avoid changing the tuning frequency of the coupler when the temperature changes. By the way, the last option is not so bad. It will become clear why later.

As a relay, I used SANYOU SZ-S-212L with a winding voltage of 12 volts. If you use SZ-S-224L with a 24 volt winding, you can avoid a large voltage drop on a long control cable.

So, place all the parts in the case and solder all connections with the shortest possible wires. I got this box:

Such a device can easily handle 1 kW!

Now you need to make sure that the phase shifts are formed correctly. To do this, load each of the 4 antenna ports with a load of 100 Ohms, and load the remaining two ports with 51 Ohm resistors (6 resistors in total) and use a dual-beam oscilloscope to check the phase correspondence on the connectors, according to the table below:

Direction	K1	K2	K3	Ant1	Ant2	Ant3	Ant4
Yu (Ant1)
Z (Ant2)
C (Ant3)
B (Ant4)

The direction to "west" is formed in the absence of control voltage.

As an example, I will give oscillograms of two ports:

Phase shifter port -90 deg

The signal amplitudes must be as identical as possible!

The next stage is the manufacture of quarter-wave transformers to power each vertical. They are made of a cable with a characteristic impedance of 75 Ohm and Ku>0.75, otherwise their physical length will not be enough to connect to the box. I used SAT-50 with Ku=0.82. The physical length of such a cable is calculated as follows:

1. Wavelength 300/7.1=42.25m

2. Quarter: 42.25/4=10.56m

3. Physical length: 10.56*0.82=8.66m

You cut off a little more from the cable coil and adjust it exactly according to the analyzer - the Q in the cable passport does not always correspond to reality! I used the AA-330 (having previously switched the 75 Ohm bridge inside) in the following connection circuit (the opposite end of the cable must be short-circuited):

Look at the desired frequency at the peak of the green graph. If the end is not closed, then the readings will be as follows (it is smeared and in this case it is difficult to adjust the line):

On ready-made cable transformers, in the amount of 4 pieces, we string M600NN 20x12x6 rings at the antenna feed point in the amount of 38 pieces, terminate and roll into a coil:

Now we make the control panel according to the diagram below:

I used a pair of ONTs-VG as connecting connectors.

We wrap three or four layers of coarse electrical tape on each fishing rod at a distance of 60-70cm from the bottom - in order to avoid damage to it on the upper edge of the stake.

For each vertical we make 8 counterweights 8m long.

We make an equivalent load. Its power depends on the power supplied to the system. At 100 watts, four 200 Ohm OMLT-2 resistors connected in parallel are sufficient.

Well, now everything is ready for going outdoors!

The first thing to do is to find the most flat area possible. We make markings on it, taking into account the fact that all the antenna radiates along the diagonals of the square and drive the stakes 40cm deep so as to get a distance of 1/4L=10.6m on each side of the square.

Next, we lay out on the ground (it’s better to raise it as much as possible, but how will it work out) one system of counterweights in a 90-degree sector, according to the diagram below (conditionally only 3 counterweights are shown in each sector:

Counterweight layout

Now, let's measure a piece of wire for the vertical web. I used one thread from the "vole" P-274, 10 m long. We attach this section to the fishing rod in three places with electrical tape.

We lift the fishing rod and secure it with two clamps so that the wound electrical tape lies just at the upper edge of the corner:

We connect the antenna analyzer to the resulting system. Our task is to tune this single vertical to the middle frequency of the range, namely 7100 kHz, while it is important to obtain an impedance of 50+0 Ohms at this frequency! If the figure does not work out, then, depending on the value of the active part of the impedance, manipulations are made with the counterweights (their number, placement in space) until approximately this figure is obtained. The diameters of the emitter conductors and counterweights also contribute to its formation. I received 48+0 Ohms. Do this in turn with each vertical, but the length of all four verticals must be made the same! At the same time, you don’t have to remove the already raised verticals - you just need to break their connection with anything below.

Fishing rods in working position

Now, in the center of the square we mount a “magic box” and connect to it what we have prepared at home: 4 cables to verticals, 50 Ohm load, feeder, control cable:

Here you go! Now you can carry out tests. To begin with, this needs to be done using the passive method: we measure the SWR - in case of incorrect connections, it will be large. For example, as soon as one of the verticals is disconnected, the system becomes so unbalanced that the SWR will be more than 5. In a correctly constructed SWR system<1.3. Впрочем, если не удалось получить приемлемый КСВ при правильной диаграмме, то не думайте, что ошиблись с изготовлением системы - все дело в импедансах полученных вертикалов. Просто примените СУ между магистральным кабелем и "коробочкой".

Now, it is advisable to estimate the resonant frequency of the system (this is not the same as resonance in terms of SWR). To do this, you need to measure the power released by the phase shifter equivalent at different frequencies of the range - where it is minimal and is the system tuning frequency. It should be noted here that towards the edges of the range this power increases (less is emitted into the air), but does not exceed 10% of the supplied one. That is, if the supplied power is 1 kW, then, with a margin, you can set the equivalent to 100 watts. In reality, the indicators are lower and 30 parallel-connected OMLT-2 resistors will cope with the task. As for the SWR band, in the 1 MHz band the SWR did not exceed the value of 1.2..

The antenna design diagram is shown below:

The F/B received in my case was 5-6 points. Based on the signal level, some correspondents later wrote that UA9CNV was the loudest with R9C. Thus, we can confidently say that the experiment was a success and we can recommend similar portable systems for field trips.

For myself personally, I noted that in RDAC there is no point in using 4 verticals - two (west-east) are enough. In this case, the “magic box” is used in the same form, but only antenna ports 4 and 1 are used. In this case, 1/4 power cables must have a characteristic impedance of 50 Ohms and their Ku can be 0.66.

#1
Dmitry, you write that you adjust each pin to 50 ohms by changing the position of the counterweights.
Is this good? After all, the earth may have different conductivity at different times of the year, there may be precipitation, etc. And the counterweights must be grounded one way or another...
#2
There was no talk about grounding the counterweights in any other way. We are talking only about their placement on the ground in a certain way. In each (any) place, the parameters of the earth do not change so widely even during cataclysms. Therefore, this work needs to be done anyway.
#3
Dmitry, good afternoon. You said that you found 9.6m fishing rods. But these are CARBON PLASTIC fishing rods, not fiberglass (in Moscow, for example, Chinese fiberglass is available only up to 6m inclusive). And carbon fiber is usually pierced due to electrical conductivity (I encountered this myself. How is it in your case?
#4
And one more note. I have been using the stationary version of the foresquare for more than two years. So, according to all the holy calendar, it is advisable (if they are in such quantity as yours) to be raised by at least a meter and a half, that is, the feed point of the pins should be raised by this amount. In this case, your reactive field will be closed to the counterweights almost completely (estimated, losses in the ground will be no more than 5%) Otherwise, for good operation of the antenna, a significantly larger number of counterweights is desirable.
#5
I won't say anything about fishing rods. However, carbon fiber costs from 10 thousand rubles for such a fishing rod, they cost me much less, which means the share of carbon fiber there is negligible. And, judging by the result, which satisfied everyone, there is no point in paying attention to the material of the fishing rod. I didn't have it stitched.
About counterweights - everything is true. But as it is - 200 radials for a field antenna is too much. But the obvious things about how to make a grounding system and about the desirability of its removal from the ground, in relation to field antennas, need not be discussed. Regarding the 5% losses, in your reading, I very much doubt it, because to achieve this figure it is not enough to raise the counterweights by a meter, it is necessary to greatly increase their number from the existing one. As a result, the system ceases to be portable..
#6
Regarding the material - yes, indeed, if it works, then let it work)). Regarding the counterweights - this is what I meant: four radials from each vertical, raised to a height of two meters (so that the wife could hill up potatoes at the dacha))) provide isolation of the reactive field in such a way that if you, in addition to them, draw another, let's say twelve radials along ground - they do not reduce the impedance of a separate vertical, which indicates the effectiveness of these very raised radials, you will agree. Therefore, I work on four radials from each vertical, and in principle I have succeeded in diexing... back and forth does not suffer from this. ON4UN writes the same thing in his book about raised counterweights... Again, I don’t bother with recommendations, so, a comment for thoughts...))) Good luck!
#7
Dmitry, you say things that are correct, but obvious. Imagine a field vertical design with radials raised by 2m. This thing will no longer be portable. Undoubtedly, raised radials are always better. It should also be noted that they will need to be configured.
#8
Dmitry, what do you think, if 2 vertical triangles are powered using this method, will this system work?
#9
Yes it should. Pay attention to the phasing. And, for sure, you will need to think about the characteristic impedance of the power cables if you want to infinitely bring the SWR closer to 1.
#10
radiohamra9da (Friday, 05 October 2012 12:24)

Dmitry, pay attention to setting up the quarter-wave transformer using an antenna analyzer. The end of the cable must be open. When configuring a half-wave repeater, it is closed (shorted). And look, search at the expected frequency of 0 reactivity. Unfortunately, some AA-330 owners are looking for 50 ohms, others SWR = 1.
#11
Nikolay, hello. How does this contradict what I wrote?
#12
Dmitry, if I may have questions about the rings
#13
So ask! :)
#14
The question is about the rings. If not amidon, did you try something else?
#15
I didn’t install ICQ, I have Skype - fedorifk, you can transfer it there
#16
Haven't tried it, but it should work. It’s just that the size of our rings will be larger, all other things being equal.
#17
Thank you for reading. We have M2000HM1 in stock with a diameter of 45 mm and the second position M1000HH3 with a diameter of 120 mm, these are large. more cores from LC-5. Is the inductance of the coils always 1.13 µH?
#18
I'll bother Dima again. THE AMIDN RINGS ARRIVED, started everything up and set it up. Only the capacitors had to be reduced to 120pf
since with C = 197pf the resonance is at 6500 and so at 7100. Is the capacitance involved in the phase shift? I feel that somewhere is not quite what I wanted. I re-read your entire correspondence with Barsky, but in practice it turns out more and more fun
#19
Sergey, what did you mean when you wrote “resonance at 6500..” - how was it measured?
#20
Dim Hello, Happy New Year! I don’t like to write, I wanted to talk to you on Skype. In short, the verticals of 9-70 rings T200-2 I use the A-200 analyzer. When the capacitance is 197 pf, the resonance on the analyzer is somewhere around 6510, I set C = 120 goes to 7100 but then the phase shift probably changes incorrectly. I tried to work yesterday with an amplifier; there is a diagram in the evening that is clearly visible. But there are doubts about the calculation formula?
#21
measurements from sheka are already, for clarity
#22
Sergey, Happy New Year.
As I wrote, you cannot rely on SWR readings
Here is my quote from the text above: Now, it is advisable to estimate the resonant frequency of the system (this is not the same as resonance by SWR). To do this, you need to measure the power released by the phase shifter equivalent at different frequencies of the range.
Return the PV to its previous form, in which, as you wrote, everything was configured and do not interfere with it anymore.
Measure the voltage at the equivalent and describe the readings.
#23
thanks, I'll go take it off and put everything back in place
#24
50% of transceiver power first readings C=120/190 F=6.6 MHz 5.1/7.3:
F=6.9-4.0/5.7
F=7.0 3.2/4.8
F=7.050 2.7/4.3
F=7.1 1.9/3.6
F=7.2 1.4/2.4 volts
at the entrance about 30v. I don't know what to think
#25
try setting the peak capacity to 200?
#26
1. Carefully re-read what is written above.
2. Make the PV strictly as written and DO NOT touch it again. No need to think about adjusting containers and other things
3. Find the point with the minimum power allocation at the equivalent. Don't look at the SWR AT ALL
4. If each individual has a vertical Rin = 50+0 Ohm, then the frequency found will help you understand what needs to be done, namely (in this case) the verticals need to be lengthened.
5. I doubt that your verticals have exactly this impedance, so either achieve it (as I wrote), or leave everything alone, understanding how much power is spent on heating the resistor) and work on the air with pleasure.
6. PV is balanced when the equivalent is 0 Volts! But for this you need to load its outputs with the correct loads. Can anyone be sure that the FV connectors are ideally 100 Ohms?
7. About “I don’t know what to think” - analyze the results! It can be seen that the resonance of the system is outside the range (above). Convert the resulting voltages into power and decide how much such losses suit you. I was aiming for 0.03 watts at the resonance frequency, but I don't think it's worth aiming for after spending days on tuning. In your situation, just follow step 2 and have fun...
#27
Dim, thank you for your time. I think you, too, have been digesting everything for more than one day. Probably there is not enough theory. Also, if you measure each pin, it’s enough to simply turn it off. Is the loop from the GO or is it better from the vertical? I measured it on each separately and it’s not abnormal. The rest R is more than 100 ohms. I’ll check for sure tomorrow afternoon
#28
Sergey, it is important to have physically identical (length, thickness) verticals rather than identical Rin. Tune one by tearing the others off the cable and make the others perfectly the same. Moreover, in your case you need to tune them somewhere at 6850 kHz, because their Rin is strong<50 Ом. Кстати, именно поэтому у них на конце шлейфа >100 Ohm. You will get resonance where you need it, but the SWR will be around 1.3. There is nothing scary about this. It is more important to have a balanced system. If you need good coordination, place the control system at the entrance to the civil defense. But I’ve never done that, there’s no need for it.
#29
Dim, I realized that I need to lengthen them, I don’t know how it will turn out, everything has melted, the water is standing, we laugh, but it’s still warm, but I’m fiddling around like everyone else in winter. In any case, I’ll report back. I heard quite well last night working with Korea and Venezuela.
The main thing is that I can already hear it quite well. While I’m at work, I’ll get to it a little later after lunch
I'll take a look at it on an oscilloscope at work now.
#30
Dim got to two pins, but parallel. On one at F=7190 R=49 X=24 ksw=1.4 Z=52
on the other at F=6900 resonance
R=51,X=0, Z=51-52om ksv1,2 both are like twins in size, but the first one next to it is 4 meters of mesh fence and guy lines from the vertical - 18 m, the second one is free, that’s how to twist them. solid pipes 6m and 4m at the joint it took cm-30 a very long run up I didn’t even think about. I’ll put on the boots tomorrow and move on to the other two. That’s all for now, I’ll finish it off.
#31
Sergey, how are you doing?
#32
Hello Dim. I extended the pins to 10.7 m. I didn’t have time to measure (resonance) everything melted, I’ll probably have to wait. I’m working as you said and enjoying it. You can look in the cluster. I saw a 24 m pin on the RA6LBS and on it there are 4-element wires for 80 - I’m considering it for the spring this option. It’s a pity I can’t calculate it in mana, I just didn’t use it.
#33
No need to count - do it and have fun! If I say that the spacing in that design is too small and in general this is a very compromise solution, you will be upset. Therefore, I will remain silent)) But the idea is not bad for those who have problems with space.
#34
Hello Dmitry!
If I install two verticals at 40 meters. I want the resonance of the system to be at 7.100. What frequency should I roughly tune a single vertical to? To almost immediately get to the right place. I understand that I then need to measure the power and voltage at the equivalent). But that’s all the same, in order to raise and lower the pins as little as possible. If Barsky is not mistaken, with a system of two verticals, you need to tune single verticals 60-50 kHz lower than the resonance frequency of the system. And you tuned it to 7.100.
Where is the truth?
Thank you.
73.
------
73.
#35
True in both cases. It all depends on the execution of the verticals and, ultimately, on the impedance of each vertical. For example, in a system of two dipoles, each of which is exactly 50+0 Ohms, the resonance of the system was exactly where the resonance of each of the dipoles was. I once posted the resulting graph on the forum many years ago. In your case, if you organize a good ground, make the pins longer, as Alexander wrote correctly. Please note that the SWR at the input to the PV will increase, but do not pay attention to this.
#36
Dmitry thanks for the answer.
Another question: What is the best option for counterweights and their length?
I'm asking for the hiking option.
I think I should put a maximum of 24 pieces under each pin. The counterweights will be on the ground.
What length should I take them? 0.1 lambda or 0.25 each.
Or maybe make 16 pieces of 0.1 lambda for each pin?
And I don’t want to do much (weaving a web) and I want the earth to take as little power as possible.
And in general, does the number of counterweights affect F/B?
And one more question: Is it necessary to connect the counterweights to each other where they intersect, that is, at the point of intersection, connect them, and cut off the excess?
What do you think?
Thank you.
73.
#37
I think the best option is what I did (that’s why I did it). There are many factors. Of course I want them bigger and taller, but all this confusion when moving will start to tire me. Many short ones are an option, but there should be a lot of them. If directly on the ground, then 0.2L is possible. In general, making soil for the vertical is 80% of the work. All laws are known.
Place the counterweights exactly as in the diagram above - there is no need to spread them inside the square - there will be mutual influence. However, for a stationary option it makes sense to bury them and connect them.
#38
Hello Dmitry! Everything is clear.
I have a question and request. You are strong in someone. antenna calculation programs.
Do you have experience in calculating such vertical dipoles with a capacitive load.
Power supply through extension coils is most likely a communication coil.
Here is a photo from the company's website
Http://www.texasantennas.com/index.php?option=com_content&view=article&id=97&Itemid=109
I read that they can also be powered actively. Can you help with the calculation?
The height of the dipole is 7.315 meters, if converted from inches.
You also need the dimensions and data of the coils.
#39
I can't help you with the calculations. All antennas shortened in different ways cannot be accurately calculated. Only taking individual impedances at the working height of each element and using this data in calculations. Or a little simpler: just individual impedances and the model must be adjusted to them. I thought so about 40-2CD and got an excellent result - I posted it here. I really spent a lot of time trying to figure out the details. But then it could have been found, but now it is not.
#40
I re-read what I wrote - somehow it turned out categorically) Oleg - I will always help with advice, but I will not undertake calculations. Excuse me. There are a lot of nuances and they all really take up time. Formulate your questions and we can choose a time to discuss. By phone - it's more correct.
#41
Dmitry understood everything. If anything can be discussed on Skype. But a little later. Work and all sorts of things have piled up. There’s not even enough time for DH owls hi! hi! 73.
#42
Dima, greetings
If the counterweights at the vertical are located asymmetrically, then the currents in the counterweights are not compensated and the antenna appears horizontal polarization with high radiation angles, that is, up to half the power will be radiated to nowhere, spoiling F/B on short paths.
For the 40m range, it is better not to bury the counterweights, but, on the contrary, to raise them together with the power points of the verticals by a couple of meters; with this raising of the counterweights, losses of the reactive (near) field in the ground will be minimized.
For this antenna, two oppositely located raised counterweights for each vertical will be sufficient. Counterweights can be positioned tangentially to the circle formed by four verticals.
I wonder what resistance R+jX was able to be obtained on the ferrite rings attached to the cables? I made such an antenna a long time ago without rings, but there was a lot of extra cable in the quarter-wave sections - due to which I later increased the perimeter of the antenna and raised the gain a little. The excess cable can be wound on rings; it makes sense to make the resistance R or X at least 500 Ohms in order to remove currents from the outside of the braid of the quarter-wave sections.
#43
Hello Igor.
I wrote everything correctly, but it’s not important for a traveling design. Firstly, for counterweights lying on the ground, their symmetry is not so important. Moreover, with this arrangement we reduce the mutual influence of neighboring grounding systems on the system as a whole. This design usually has 5-6 F/B points. If the counterweights took part in the radiation, such an indicator would not have been achieved on nearby paths.
Secondly, it’s natural to raise it better (I wrote about this above in the comments), but the mobility of such a system becomes questionable.
Two counterweights here (as in any such system) are not enough. All this will work, but the losses are obvious.
I didn’t measure R+jX specifically for these segments, but I set it to more than 1 kOhm.
#44
Dima, greetings
I modeled a single vertical with two counterweights located in a 90-degree sector on EZNEC. I look at the characteristics of a single element at an elevation angle of 5 degrees (a route of 2500 km or more per jump). Real/High Accuracy land type (similar to Nec2).
The counterweights lie on the ground at a height of 5cm above the surface. The diagram has a maximum in the direction of laying the counterweights and F/B 2.01 dB. This suggests that more than -2.01 dB of the supplied power is radiated with horizontal polarization in the direction of the counterweights. The gain of such an antenna at the azimuthal maximum is -7.48 dBi.
I raise the counterweights and the feed point to a height of 2 m, and shorten the vertical itself by 2 m to reduce the error of additional gain by narrowing the diagram when raising the antenna. F/B increased to 2.58 dB gain -5.98 dBi.
Here, more than -2.58 dB of the input power is radiated with horizontal polarization.
On a raised vertical, instead of a sector, I make two opposite counterweights. Gain -6.48 dB, all power radiated vertically polarized.
And finally, to assess losses in the ground, I lower a vertical with two opposite counterweights to the ground, height 5 cm above the ground. Gain -7.88 dBi.
For two opposite counterweights, the difference in antenna gain between those lying on the ground and those raised 2m was 1.4 dB, mainly due to the loss of near-field power in the ground.
I make 8 counterweights in a 90 degree sector at a height of 5cm. Gain -7.21 dBi. F/B 2.61 dB. The gain increased by 0.27 dB compared to two counterweights at 90 degrees. mainly due to an increase in F/B - that is, due to the radiation of a horizontally polarized wave. Losses in the ground compared to two radials in the 90 deg sector. have hardly decreased.
This is how the arithmetic turns out. Even 1 dB in antenna gain for transmission on low frequency bands is a huge difference.
A short vertical with two opposing raised counterweights at a height of 2m beats a full-size vertical with eight counterweights lying on the ground by more than 3 dB in gain.
73,
Igor
#45
I read the correspondence above about the need to adjust raised radials - they do not need to be adjusted, they are taken of arbitrary but equal length. You can take a length from 7 to 10 meters. Tuning a single vertical to the required frequency is done by turning on the coil at the power point. I make coils with aluminum wire APV-4 in PVC insulation, diameter 2.2 mm, bolted connection with vertical wire and cable, I make verticals from the same wire. Manufacturing and tuning a coil locally for a specific land is easier than cutting and building counterweights. The frame for the coils is an ordinary plastic sewer pipe with a diameter of 50mm. The coil is fixed to the frame with electrical tape.
#46
Igor, good analysis, but it just says that the counterweights shifted into the sector redistribute the radiation. In your opinion, how important is the overall increase in antenna gain at an angle of 5 degrees due to horizontal polarization? In other words, what is better: for 5 degrees of elevation, 2dB gain of purely vertical polarization or the same 2dB gain, but with different shares of vertical and horizontal? It seems to me that there can be no categorical answer to this, because... all these polarizations at the end point for different correspondents are not taken into account at all. And at different races... Moreover, it doesn’t matter anymore.
Regarding the adjustment of counterweights, I still see two main points:
1. they must be perfectly symmetrical electrically and geometrically
2. they must be configured so that it is as easy as possible for currents to flow into them. An extreme case, for example, symmetrical counterweights of 50 cm. You won’t argue that this is enough.
3. They should be raised as much as possible. The higher, the fewer of them will be required.
Another thing is that for our situations, plus or minus a tram stop will not play a role, because there are other disturbing factors. But it needs to be taken into account.
#47
I agree that with equal gain, it doesn’t matter whether one or two polarizations generate radiation, but don’t forget that for a single vertical, the circular diagram is lost, that is, with a sector arrangement of counterweights, the vertical becomes a directional antenna and the gain is equal only at the maximum of the diagram.
If you combine 4 verticals with sector counterweights into one antenna system, then each vertical’s own radiation is directed in the opposite direction from the center of the system, and accordingly, the total radiation of the system in the required direction will be less.
Ideally, oppositely located counterweights should be electrically symmetrical - in this case, currents flowing oppositely in the counterweights create electromagnetic fields that are completely compensated. In reality, two verticals installed on the ground at a distance of 10 meters with raised counterweights have different input impedances. The ground, even under one vertical, often has different parameters under the counterweights, and balancing the currents even in two opposite counterweights is not an easy task - it is necessary to use identical current detectors, possibly assemble a bridge circuit to balance the currents when the length of a single counterweight changes. I have not yet mastered this technology even in stationary conditions, and there is nothing to say about field conditions. The same problem exists when counterweights are located on the ground, and does not depend on the number of counterweights. If it is not an easy task to balance the currents in two opposite counterweights, then doing this for four counterweights will be quite difficult.
Symmetrical counterweights of 50 cm - there is a whole class of verticals with asymmetrical power supply, including commercial products where the counterweights are close to 50 cm in length. I have plans to install a phased array at my summer cottage within a month from this type of verticals at 21 MHz, to avoid stretching the counterweights onto individual posts.
#48
The trick here is that the main direction of such a vertical is precisely in the forward direction of the entire system, when THIS vertical is connected in the direction of the correspondent. Naturally, its radiation in the rear direction is minimal, but that’s exactly what we need! Although whoever studied it is a mutual influence .. How much better it is, in the sense. I think that this is more important than later bothering with unbalancing the system due to the greater influence of the antennas on each other, if the radials were arranged in a circle (their counterweights would inevitably intersect). I think that there is no need to bother with hundredths of dB - we need to do it and work on the air. Both experience and your analysis at EZNEC have shown this.
As for asymmetrical antennas, I agree, but I wrote specifically about the BEST path for braid currents, and it (the current) is maximum precisely in the center of the dipole, i.e. when both halves are electrically symmetrical.
I think that at 21 MHz 2el yagi raised on 10m will work better than 4SQ :)
#49
On 4SQ the light did not converge like a wedge, there are also more serious antennas, for example 8 circle. I want to make part 8 circle but with a large spatial separation of the halves, the diagram will have a large gain of the main lobe and ears, especially for working in digital JT65/JT9, with switching back and forth. Yagi-type antennas are inferior to phased verticals in the speed of changing direction. And phasing 8 circle is much simpler than 4SQ - as with two phases of verticals, it is performed with a conventional LC chain with a two-beam oscilloscope, usually takes 15..20 minutes. For the west-east field option, this is a simple and effective antenna.
#50
Well... 8 - you need even more space. About the efficiency of turning, perhaps the only plus))
#51
the version of half of the 8-circle range of 40m west-east fits into the remaining two-thirds of the 10-acre plot, the remaining third is occupied by a house and all sorts of buildings. Two raised counterweights per vertical. I took it apart about a month ago, in August-September last year the antenna gave about 700 Japanese in CW - it worked out about 99% of those who gave a general call on the band in my transmission window.
#52
That's what I'm talking about: give this 2/3 of the plot... This is a feat ;-)
#53
counterweights and power points are raised 2m above the ground, there is a vegetable garden and a garden under the antenna, all cables, counterweights and verticals are attached to racks, in the ground there are only racks - everything else is overhead, accordingly, only the area for racks is occupied on the ground (I use steel corners, fiberglass tubes , fishing rods). The stands only interfere with mowing the grass on the lawn - you have to walk around it.
#54
Hi all! I plan to install a 40-meter vertical ant in the spring. Question about the counterweights - what material is copper or can it be galvanized wire? How much does the antenna efficiency decrease when galvanizing?
#55
Copper, maybe aluminum. No need for galvanizing. No one has considered how much, but you can put the material on your own in MMANA and see the reaction, taking into account the restrictions, of course.
#56
Dmitry, thank you for your answer. My antenna is a directional antenna at 7 MHz Goncharenko. After reading all the comments and opinions, I came to the conclusion that for this antenna system the counterweights should be made as shown in the figure above (in the antenna itself, according to the recommendation, it is not clear how to correctly position the counterweights - after all, there are 8 counterweights under the active emitter, at least 4 more under the 4 passive ones, and they are all intertwined one under the other creating a web and it is unknown how it affects the efficiency of the antenna). I will do as you recommend, spreading it outward from the middle. The counterweights and the antenna itself will be at a height of 2.5 m from the ground. Dmitry, will I do the right thing? Basil.
#57
If the height of the system is 2.5 m, then 1 counterweight is sufficient, with t.z. losses. But it’s even better to make them in pairs and configure them in pairs, like a dipole - this will be an excellent system and clearly vertical polarization.
#58
Dmitry thanks for the answer. If you make dipoles, then the question of placing counterweights again arises - under the active element there are 8 pr. to 10.4 located evenly around the circumference, but how then to place the pr. under the passive elements? From the central emitter to the pass. elem. 6 meters. It turns out that they intersect. Basil.
#59
I don’t want to go into details of the incomprehensible design, to which you did not provide a link, but try to place the counterweights so that each vertical has two symmetrical counterweights and they are configured like a dipole. If not, start with one counterweight.
#60
Dmitry good evening. Antenna link http://dl2kq.de/ant/3-30.htm. There are options in the placement of counterweights. 1 is the same as in your version. 2- make the counterweights dipoles (there is an antenna analyzer). 3-place the counterweights under the passive elements in a circle without connecting electrically with other counterweights. There is an empty space under the antenna so you can work all summer to get the result. I need work at small angles and have good gain. Vasily.
#61
Well then it’s strange that you’re asking me questions and not DL2KQ. In this design, it would be advisable to carry out preliminary modeling. I do not rule out that there is some optimal arrangement of counterweights. For now, I’m in favor of using them in pairs: one inside towards the vibrator, the second outside the system - away from it. And if you have such conditions, then, it seems to me, you would be better off considering the option of using SpitFire, but in 4 directions.
#62
Thanks Dmitry for the answer. There is still time to model and think about the antenna. Thanks for communication. Basil.
#63
http://www.egloff.eu/index.php/en/
Dmitry, what is the simplification?
Maybe like the author?
#64
#65
Dmitry, hello!
Your calculated data: L= 1.13 μH, C = 226 pF.
From the formula we find Z = 70 Ohm.
Did you really calculate for 70 ohms or is there an error somewhere in the original data.
For Z=75 Ohm L=1.13 µH C = 200 pF
#66
Sergey, I don’t know what formula you used to calculate 70 Ohms, but I can assume that according to the formula given in the text FOR LINES. You can't use it. Secondly, initially Cx is calculated based on Rline = 100 Ohms, and Lx - from 50. Everything is fine, do as written;-)
#67
#68
You need to do exactly as I wrote. If L=1.25, then you need to rewind the turns to 1.13. The ratio of L and C in the circuit should be exactly this for this R. If you want to calculate for another R (but you didn’t mention this), then you need to recalculate the entire system, yes.
#69
It happens when the impedances of the verticals are low (shortened verticals), it is actually possible to recalculate the system not at 50 ohms, but at 35 ohms, for example. Just agree on the input and that’s it. You just need to understand that the R line on the ring is the same about 100 Ohms and the SWR line will still be increased.
#70
In general, C=1000000/(2ПFXc), where Xc=100 Ohm (in a 50 Ohm system), C in pF.
L=X/(2ПF), where X=50 Ohm, L in μH, F in MHz.
#71
Thank you, Dmitry.
There is no special need to recalculate for other resistances. By spring, I slowly began making an antenna for traveling. I will customize it according to your recommendations.
#72
After winding the transformer, does it make sense to fix the turns, for example with hot glue or lacquer cloth?
#73
Enough plastic clamps at the beginning and end

It’s impossible to even imagine how many antennas are growing around us: mobile phone, TV, computer, wireless router, radios. There are even antenna devices for psychics. What is a HF antenna? Most non-radio people will answer that it is a long wire or a telescopic pole. The longer it is, the better the reception of radio waves. There is some truth in this, but it is very little. So what size should the antenna be?

Important! The dimensions of all antennas must be commensurate with the length of the radio wave. The minimum resonant length of the antenna is half the wavelength.

The word resonance means that such an antenna can operate effectively only in a narrow frequency band. Most antennas are resonant. There are also broadband antennas: for a wide band you have to pay for efficiency, namely gain.

Why does the stereotype work that the longer the HF antennas, the more effective they are? In fact, this is true, but to certain limits, since this is typical only for medium and long waves. And as the frequency increases, the antenna sizes can be reduced. At short waves (lengths from approximately 160 to 10 m), antenna sizes can already be optimized for efficient operation.

Dipoles

The simplest and most effective antennas are half-wave vibrators, also called dipoles. They are powered in the center: a signal from the generator is supplied to the dipole gap. Amateur radio portable antennas can operate as both transmitters and receivers. True, transmitting antennas are distinguished by thick cables and large insulators - these features allow them to withstand the power of transmitters.

The most dangerous place for a dipole is its ends, where voltage antinodes are created. The maximum current of the dipole is in the middle. But this is not scary, because the current antinodes are grounded, thereby protecting receivers and transmitters from lightning discharges and static electricity.

Note! When working with powerful radio transmitters, you may receive shock from high-frequency currents. But the sensations will not be the same as from a blow from a socket. The blow will feel like a burn, without shaking in the muscles. This is due to the fact that the high-frequency current flows over the surface of the skin and does not penetrate deep into the body. That is, the antenna can burn the outside, but the inside will remain untouched.

Multiband antenna

Quite often it is necessary to install more than one antenna, but this is not possible. And in addition to a radio antenna for one band, antennas for other bands are also needed. The solution to the problem is to use a multi-band HF antenna.

Possessing fairly decent characteristics, multi-band vertical antennas can solve the antenna problem for many shortwave operators. They are becoming very popular for a number of reasons: lack of space in cramped urban environments, the growth in the number of amateur radio bands, the so-called “bird license” life when renting an apartment.

Multi-band vertical antennas do not require much space for installation. Portable structures can be placed on the balcony or you can go with this antenna somewhere to a nearby park and work there in the field. The simplest HF antennas are a single wire with asymmetrical feeding.

Someone will say that a shortened antenna is not that. The wave loves its size, so the HF antenna must be large and efficient. We can agree with this, but most often there is no opportunity to purchase such a device.

Having studied the Internet and looked at the designs of finished products from different companies, you come to the conclusion: there are a lot of them, and they are very expensive. All these designs contain is a wire for HF antennas and one and a half meters of pin. Therefore, it will be interesting, especially for a beginner, to find a fast, simple and cheap option for homemade production of effective HF antennas.

Vertical Antenna (Ground Plane)

The Ground Plane is a vertical ham radio antenna with a long quarter wavelength pole. But why a quarter and not a half? Here the missing half of the dipole is a mirror reflection of the vertical pin from the surface of the earth.

But since the earth conducts electricity very poorly, they use either sheets of metal or just a few wires spread out like a chamomile. Their length is also chosen equal to a quarter of the wavelength. This is the Ground Plane antenna, which means earthen platform.

Most car antennas for radios are made according to the same principle. The wavelength of the VHF radio broadcast is about three meters. Accordingly, a quarter of a half-wave will be 75 cm. The second beam of the dipole is reflected in the car body. That is, such structures must, in principle, be mounted on a metal surface.

Antenna gain is the ratio of the field strength received from the antenna to the field strength at the same point, but received from the reference emitter. This ratio is expressed in decibels.

Magnetic loop antenna

In cases where the simplest antenna cannot cope with the task, a vertical magnetic loop antenna can be used. It can be made from a duralumin hoop. If in horizontal loop antennas their technical performance is not affected by the geometric shape and method of power supply, then this does affect vertical antennas.

This antenna operates on three bands: ten, twelve and fifteen meters. It is rebuilt using a capacitor, which must be reliably protected from atmospheric moisture. Power is supplied by any 50-75 Ohm cable, because the matching device ensures the transformation of the transmitter output impedance into the antenna impedance.

Short dipole antenna

There are shortened 7 MHz antennas, the arms of which are only about three meters long. The antenna design includes:

two shoulders about three meters;
edge insulators;
ropes for guy ropes;
extension coil;
small cord;
central node.

The coil winding length is 85 millimeters and 140 turns wound closely. Accuracy isn't that important here. That is, if there are more turns, this can be compensated by the length of the antenna arm. You can also shorten the length of the winding, but this is more difficult; you will have to solder the ends of the fastening.

The length from the edge of the coil winding to the central unit is about 40 centimeters. In any case, after manufacturing, the antenna will have to be adjusted by selecting the length.

DIY vertical HF antenna

How to make it yourself? Take an unnecessary (or buy) inexpensive carbon fishing rod, 20-40-80. Glue a paper strip with dot markings onto it on one side. Insert clips into the marked places to connect jumpers and bypass the unnecessary coil. Thus, the antenna will switch from band to band. The shaded areas will contain the shortening coil and the indicated number of turns. A pin is inserted into the “fishing rod” itself.

You will also need materials:

copper winding wire is used with a diameter of 0.75 mm;
wire for counterweight with a diameter of 1.5 mm.

A whip antenna must work with a counterweight, otherwise it will not be effective. So, if you have all these materials, all that remains is to wind the wire bandage on the rod so that you first get a large reel, then smaller and even smaller. The process of switching antenna bands: from 80 m to 2 m.

Selecting the first HF transceiver

When choosing a shortwave transceiver for a novice radio amateur, first of all, you need to pay attention to how to buy it, so as not to make a mistake. What are the features here? There are unusual, highly specialized radios - this is not suitable for the first transceiver. There is no need to choose handheld radios designed for on-the-go operation with a whip antenna.

Such a radio station is not convenient for:

use it as a conventional amateur radio device,
start making connections;
learn to navigate the amateur radio airwaves.

There are also radio stations that are programmed exclusively from a computer.

The simplest homemade antennas

For radio communications in the fields, it is sometimes necessary to communicate not only over distances of hundreds of kilometers, but also over short distances from small portable radio stations. Stable communication is not always possible even over short distances, since terrain and large buildings can interfere with signal propagation. In such cases, raising the antenna to a small height can help.

A height of even 5-6 meters can give a significant increase in the signal. And if audibility from the ground was very poor, then by raising the antenna a few meters the situation can improve significantly. Of course, by installing a ten-meter mast and a multi-element antenna, long-distance communications will definitely improve. But masts and antennas are not always available. In such cases, homemade antennas raised to a height, for example, on a tree branch, come to the rescue.

A few words about shortwaves

Shortwave operators are specialists with knowledge in the field of electrical engineering, radio engineering, and radio communications. In addition, they have the qualifications of a radio operator, are able to conduct radio communications even in conditions in which professional radio operators do not always agree to work, and, if necessary, are able to quickly find and fix a malfunction in their radio station.

The work of shortwave operators is based on shortwave amateurism - the establishment of two-way radio communications on short waves. The youngest representatives of shortwave frequencies are schoolchildren.

Mobile phone antennas

A dozen years ago, small beads stuck out of mobile phones. Today nothing like this is observed. Why? Since there were few base stations at that time, it was possible to increase the communication range only by increasing the efficiency of the antennas. In general, the presence of a full-size antenna for a mobile phone in those days increased its operating range.

Today, when base stations are stuck every hundred meters, there is no such need. In addition, with the growth of generations of mobile communications, there is a tendency to increase frequency. HF mobile communication bands have expanded to 2500 MHz. This is already a wavelength of only 12 cm. And not a shortened antenna, but a multi-element one can be inserted into the antenna housing.

You can’t live without antennas in modern life. Their variety is so huge that I could talk about them for a very long time. For example, there are horn, parabolic, log-periodic, directional antennas.

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