HF antennas for work in the field. "Antenna Constructor" is my field antenna for QRP. On air with a computer

I decided to write not just a review, but a practical article about shortwave communications. Moreover, the “soap boxes” of the LPD\PMR range are only suitable for organizing grassroots communications such as “camp/camp - went into the bushes to recover/akhtung, fisheries supervision is on”, and in the NE it is very difficult to contact the “dead zone” of the first jump, and this is 80...300 km.
In general, everything at home that I wasn’t too lazy to redo and I decided to get out to the suburbs for a day and at the same time work on air field conditions... A little theory. In practice, quite often it is much easier to organize communications over several thousand km than to establish reliable communications within 120...300 km. This happens primarily because the surface wave from the transmitter has already scattered and been absorbed, and the spatial wave, reflected from the ionosphere, has “flew past”... Here is an explanatory photo...


In order to have reliable radio communication with correspondents who are in the dead zone, first of all, special antennas are used, more precisely they are called AZI (anti-aircraft radiation antennas). They are called that because their maximum radiation occurs vertically upward (to the zenith) and the emitted radio waves, reflected from the ionospheric layers, “fall back” exactly blocking this very dead zone. The frequency range is limited to 2MHz~10MHz, the uppermost “limit” is 14MHz, since Radio waves are more high frequencies are reflected weaker by the ionosphere, “flying away” into outer space. In our case, the most accessible amateur bands are 80 meters (3.5 MHz), 40 meters (7 MHz), 30 meters (10 MHz, exclusively for those who like to work with telegraph) and 20 meters (14 MHz ) The simplest AZI is a “horizontal beam”, which has a length of 15...25 or all 30 meters (it is not recommended to do more than 30 meters, firstly it’s a chore to stretch, and most importantly there are no coordinated improvements), stretched in 1.0...1.5 meters above the surface of the earth and connected through an External Matching Device (if your radio station does not have a built-in tuner) to your transceiver. Here is an explanatory picture (by the way, I already showed it once)…


Pay attention to grounding, it is necessary for the antenna to operate effectively. And you don’t want to carry a 2-meter crowbar with you and hammer it in/pull it out every time, so you can make such a “grounding loop” from electrodes or some other rods that come to hand. The electrodes are cleaned of amalgam, sharpened on one side, and a thread is cut on the other side and the connecting wires are secured using nuts, screws and washers (it is very convenient to use “wings” instead of nuts). This is what it looks like in practice...


here is a photo from the “other end”...


pay attention to this moment- the “hot” end of the wire should, if possible, be insulated from the ground and insulated sufficiently well. For example, using a dry nylon rope or cord...


Even more effective is the AZI, made not in the form of a horizontally located “beam” (a piece of wire in the sense), but in the form of a horizontally located frame made of the same wire, 15...25 meters long. The shape of the frame can be triangular, square, rectangular, this is not fundamentally important. We connect the second end of the wire (which was “hovering in the air” in the above photos) to the APU ground connector/terminal. Such an antenna does not necessarily require grounding, which is often quite important on rocky/stony/sandy soil. The frame can be stretched, the wire can be attached to trees on stakes or in a clearing. It is also necessary to remember that if such a frame AZI is stretched not in an open area, but in a forest, then its effectiveness can decrease quite significantly, especially when the trees have not shed their leaves. For example, in these conditions...


I used the wire for the frame in fluoroplastic insulation and on top with a fiberglass stocking, it didn’t turn out very noticeable. Here's another explanatory photo...


Here you can clearly see how the connection to the MFJ-902 tuner is constructed. I also connected a grounding connection to it (from the series “you can’t spoil the porridge with butter”). I used the FT-817 as a transceiver and since it does not have a built-in antenna tuner/matching device, I use the MFJ-902. “Cooperative” “MFJ”, it is compact, lightweight and, most importantly, perfectly matches antennas in a wide range of wave impedance with a 50-ohm antenna input/output of radio stations. Here's what it looks like in practice...


On the “handy material” table there is an FT-817 on a case, and on the right there is an MFJ-902, “loaded” with a 10-meter piece of wire. Below under the table there is a gel battery for powering the hurdy-gurdy and you can clearly see the coil of wire from which the frame AZI was soon made. Here is actually all the belongings folded...


I took it the same way solar battery, it is to the left of the case in a camouflage bag. But I didn’t connect it this time, since the day was mostly cloudy and the battery capacity (4.5 A/h) was quite enough... Here’s another photo, a view of the very comfortable “boudoir” I built for easy on-air communication with correspondents, that they are in the nearest 100...300 kilometer zone... I practically worked on the frame AZI telephone (SSB) with Birobidzhan, Khabarovsk, but it’s not so interesting and went beyond the scope of the task I set, and most importantly, according to the actual plan, it worked with the r / lovers from the region, and this is primarily Ussuriysk, Artyom, Nakhodka, Dalnegorsk... and even barely, with the glorious city of Vladivostok, in which I have the honor of living and in the suburbs of which I am actually located. I worked on the 40-meter band, as I worked during the daytime.

But nature is happy not only with local gossip, but also with desire to make long-distance connections. Therefore, to work in the field, you need simple antennas that are light in weight and design, which can be made from scrap materials. the main task here, unlike AZI, make such an antenna so that it radiates at as small an angle as possible to the horizon in the vertical plane. The smaller this angle is, the higher the efficiency of the antenna for long-distance radio communications will be. In the simplest case, and for operation in the low-frequency HF bands, which are the 160- and 80-meter bands, an “oblique beam” antenna is used. Its length should be at least about 40 meters to work on 160 meters and at least 20 meters for the 80-meter range. For higher frequency ranges, you can limit yourself to a 15...20 meter piece of wire. And practically, to work on 80/40/20/15/10 meters, a 25...30 meter skein is enough. Here's an explanatory picture...
We are looking for a suitable “mast”, the higher the better. Trees, buildings, etc. standing separately on a high-rise building. We throw it with a weight tied at the end (the nuts are large, unlike pliers, which strive to remain forever in the tree crown when the antenna is folded), American comrades even use slingshots with spinning reels with fishing line, I myself also used lead weights, with a tablespoon cast. Also take care of the best grounding that you can think of in these conditions. You can also use counterweights instead of grounding. In this case, these are three or four conductors, the same length (25...30 m) arranged in a “cross” / “star” and stretched along the ground. For operation on bands starting from 40 meters, the Inverted Vee antenna is also quite effective. It is a half-wave dipole, the power point of which is located on a folding mast, and the ends of the “arms” are attached to the ground (through insulators). Here is the corresponding picture...


This antenna is resonant, i.e. it must be calculated for one range on which to work. Adjust it to a minimum SWR, shortening/lengthening the length of the arm. The power cable is coaxial, with a characteristic impedance equal to the input/output of your radio station. Typically this is 50 ohm. I myself use RG-58 cable. It is moderately shitty (and it consists primarily of enormous attenuation at VHF and microwave frequencies, and at HF ​​they are negligibly small), it is quite cheap, thin, light and flexible. If you want to work on several bands, then the length of the antenna is calculated for the lowest frequency range (for example, 40 meters), and at higher frequencies it is used to match the APU. Working on ranges below 40 meters is not effective, because it is very problematic to build a mast of 20 meters or more in the field, and Inverted Vee on the 80 and 160 meter range essentially turns into an AZI, due to the low suspension height . Telescopic rods made of fiberglass are now widely available, and therefore it is possible to make a fairly effective antenna for long-distance communications - a whip antenna. Here's an explanatory picture...

We take a longer fishing rod, wind 15 meters of mounting wire around it, starting from the thin end, leaving a couple of meters to connect to the APU, drive a piece of angle into the ground, and attach a rod pin to it. If necessary, we make guy wires, always made of insulating material (the wire won’t work, because it’s made of rope), so that the antenna doesn’t fall off from the wind...

Look behind the tent in the photo, I apologize for not having a better photo. For the antenna to work, it is necessary to have a good grounding or 3 counterweights. Here is an explanatory photo of the folded “mast”...


As a “corner/base” I use the base from the Severk mast...


Here is a photo of a folded and duct-taped (so that it doesn’t get lost and for convenience) “portable grounding...


I worked on this antenna the weekend before last with “digital”, or rather “slow telegraph” - JT-65, that’s actually my workplace at that time...


I took a CF-18 laptop, a FT-897 transceiver, in addition to external power, it has a couple of built-in batteries, but I matched this antenna using the NFJ-902, you can clearly see the wire that goes from this “pin” to the tuner on the right... Then it worked with correspondents from North and South America, Australia, Europe, Oceania. Well, that’s all, if in short... I wanted to add about VHF and radio communication through sporadic TROPO, but I thought about it and decided that the topic is quite specific and in conditions of isolation from civilization there will inevitably be difficulties with predicting the passage and its short duration is not particularly suitable to the concept of “confident communication”. Here are a couple of recent photos on this topic...

We are having fun working through Japanese repeaters (bands 2 meters, 70 centimeters and 23 centimeters)


And this is me at 1.2 GHz (23-centimeter amateur band) turned around in convenient location Yes, I make connections over short distances (5...15 km)…

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Nothing fuels creativity in antenna improvements like low power operation. After all, the success of QRP communication depends not only on the good sensitivity of the correspondent’s antennas, as is commonly believed by many radio amateurs, but also on the quality of the signal and the QRP station’s antenna. I often had to observe the following picture: the signal of the station giving CQ is barely discernible at the waterfall and is decoded with errors. You answer, and the correspondent gives a report 579 (often they give 599 - I consider such reports not informative, someone is just too lazy to correct the numbers in the macro). You tell him your power of 1 watt. As a rule, after this they give their power at 25-30, or even 50 watts and begin to be interested in the antenna.

I was prompted to take up field antennas by participating in such a wonderful event as the “QRP Marathon”, held annually in April by the “72 Club”. Compared to the “marathon”, all other competitions seem like a short distance race - you give it your all and relax. And not everyone who starts a marathon reaches the finish line. Here it is important not to miss a single day and it is not always possible to work at home.

This happened to me in 2012. The place in the overall standings ranged from 3rd to 5th, and there was success in the 15 and 10 meters. And then my father called and asked me to come to him for a week. I urgently began to scour the Internet in search of a suitable antenna (at that time there was nothing other than a 40-meter dipole for working in the field). The VP2E antenna seemed to me the simplest and most suitable. I made it 10 meters and left. Early in the morning and in the evening I worked on a dipole, which the neighbors kindly allowed me to hook onto the third floor balcony, and pulled the shoulders onto the trees in the yard. During the day, I carved out 1-2 hours and went to a local park, where I deployed VP2E.

After the “marathon” I came to the conclusion that it is necessary to have in reserve good antenna for work in the field. I started experimenting with VP2E. Already by the day the QRP stations were active in June, I had a tested dual-band version of this antenna (Vesti QRP magazine, No. 3). VP2E is a good antenna, but then it seemed to me that it was impossible to make it in a multi-band version. And I started looking for other antenna options.

I stopped at an OCF dipole 41 meters long. I calculated it on a computer with a low suspension point. I came to the conclusion that the optimal suspension height at which this antenna radiates at low radiation angles on bands from 17 to 10 meters is 4-5 meters. The radiation maxima are directed in both directions along the antenna surface. In this case, the radiation angles relative to the horizon are: 18 meters - 24 degrees, 15 meters - 23 degrees, 12 meters - 22 degrees, 10 meters - 19 degrees. This suited me, and I began practical implementation. First, I made a classic asymmetrical dipole and started testing. The results were encouraging. By changing the length of the arms by winding, I achieved resonance at 10, 12 and 17 meters, and the first connections to this antenna appeared in the log.

When setting up, I noticed that shortening the web by winding the wire into a coil of small diameter is equivalent to cutting it off with wire cutters. Since I never liked wire cutters as a tool for tuning antennas, I made two reels and tied them to the ends of the antenna arms. Further tests showed that if the long arm is 37.5 meters, then adjustment can be made by changing the length of only the short arm. Thus, I was able to achieve an acceptable SWR on all bands from 40 to 10 meters.

Winter came and further tests were postponed. I returned to this antenna when, during the next “marathon,” the need arose field work. I made it in the Sleeve version, while the short shoulder was made of coaxial cable RK-50-2 15 meters long. I calculated the length of the short arm for various ranges and put tags directly on the cable.

During setup, this arm was shortened by placing shut-off chokes based on ferrite latches for the cable at the design points. At the same time, I specified the shoulder length for each range and marked these points by moving the tags. The number of turns wound around the latch must be calculated in advance depending on its size.

And now the antenna is deployed on a summer cottage surrounded by a two-meter metal fence. Checking the settings and general call at 10 meters. The third time, EA3GTO answers (distance 3066 km, azimuth 254 degrees). I exchange information, switch to the 12 meter range and after 10 minutes I communicate with R9UAK (distance 3060 km, azimuth 73 degrees). From both correspondents I receive reports of 599 and this is with my power of 1 watt! Next there were connections with OK1 on 17 meters with report 599, with DO1 and HB9 on 15 meters with reports 579. I was convinced that the antenna was working. As confirmation, I provide QSL cards received for this day.

At the end of the “marathon” I had to work on this antenna for a whole week. I made at least fifty communications on various ranges with a power of 0.5 - 1 watt. Result - 1st place at 12 meters.

When I was making the antenna, I installed a choke on a ferrite tube from computer mouse 30 centimeters from the connector for connecting to the transceiver, which corresponds to ¾ lambda for 17 meter range.

I noticed that with this design the antenna works great on 17, 15, 12 and 10 meters.

In the summer, while working with this antenna from the dacha, I noticed that on some bands it is difficult to achieve SWR = 1 by changing the length of the arms. I made the antenna sheet from a single piece of wire 41.5 meters long. The power cable was taken to be 15 meters long based on its multiplicity of approximately ½ lambda for all ranges from 40 to 10 meters, taking into account the shortening factor. Powered by I.V. Goncharenko’s method. DL2KQ via latch-on transformer.

At the same time, I made a larger loop on the cable so that up to 6 turns of cable could be wound around the latch. By varying the number of turns of the cable and antenna wire, as well as changing the length of the arms and the location of the feed point, it was possible to achieve SWR = 1 on all bands. Although in this form the antenna was perfectly tuned on all bands, the work on 40, 30 and 20 meters did not suit me; it was clearly inferior to the dipole. Apparently, the low height of the suspension had an effect.

I decided to check the operation of the antenna in the form of a dipole, because with the help of a latch the power point can be placed at any point on the wire. I cast it in the center of the canvas and raised it to a height of 8 meters using a nine-meter telescopic rod without an upper arm. I checked the tuning on the main ranges by winding the shoulders. The results were positive from 80 to 10 meters. So, the asymmetrical dipole was transformed into a multi-band IV. But the winding of the shoulders created certain inconveniences - it was necessary to move the pegs securing it to the ground. I decided to check how the antenna behaves if I shorten it by placing inductors on the wire with latches? After all, on cable it justified itself. I calculated that it is necessary to wind at least 7 turns of wire onto the existing latches for a range of 80 meters. I stopped there.

So, the antenna is deployed and tuned to 80 meters. I check at 40 meters - the SWR is off the charts. At the calculated points at 40 meters, I install latches on both arms, winding 10 turns of wire on them.

I check the setting - SWR is about 1. By moving the latches along the canvas I achieve SWR = 1. Hurray, this option works! I play around with tuning to other bands using latches - the antenna is easily built up to SWR = 1.

Celebrated New Year 2014 in the village. I took the transceiver with me, deployed the antenna in the yard next to the house in the VP2E version for 40 meters, and ran the power cable through the window. In between the installation of the Christmas tree and other events, he went on air. IN this option the antenna is operational with acceptable SWR on all bands from 80 to 10 meters, but as VP2E it only works on 40 meters. That day and night I successfully worked at 40, 15, 17 and 80 meters. True, on 80 meters we had to increase the power to 2.5 watts; on other bands it worked at 1 watt. To tune to 80 meters I had to select the turns ratio on the power transformer, I got 3:5.

I always check antennas at 1 watt, then switch to 0.5 watt, and if at this power I can communicate over 1000 kilometers, then I think that the antenna deserves attention. So, the VP2E option is not alien to this antenna.

Later, before frost set in, I managed to test the two-element Yagi version at 15 meters - the results were positive. At the same time, in order to spread the canvas in the upper part, it was necessary to make a spacer from the upper leg of the rod about a meter long. The canvas was divided into working sections (vibrator and reflector) using inductors on latches. Since the arms are shortened when winding the wire onto the latches, I tied 0.5 meters of thick fishing elastic to the reels to reduce the load on the top of the mast.

Two-element Yagi variant

I plan to carry out the main work and parallel testing of this antenna in various versions during the next “marathon”. In this case, the main position will be on the summer cottage, where electricity has not yet been supplied.


The result is such a compact, lightweight and quickly deployable antenna.

WIRE FIELD three-element tri-band antenna from UY2RA fishing rods.
Start. Continue watching Ogorodno Field Antenna 2 Ogorodno Field Antenna 2
Repeated trips (to the islands) and work from the field (memorials) gave invaluable experience in the work of real radio operators: how to provide communication with improvised means. In this regard, the experience of using amplifiers is very interesting. Not the main thing, but the first thing: in this case you need a battery, preferably a large one. It is included as a high-capacity capacitor (buffer) between the 12-volt power supply and the transceiver and should smooth out current surges during transmission. Then the generator, when the power amplifier is running, is not so stressed during consumption peaks. But when using amplifiers, another problem immediately arises. In the field, of course, light and simple antennas. In the ranges of 160-80 meters there is no competition for "inverted V". But from 40 and above options are possible. Often, due to design advantages, a variety of pins win. They are especially effective from 40 meters and above..... But every medal has a downside. The pin is definitely not a receiving antenna. This disease is greatly aggravated when working with an amplifier, since GP is very effective at transmission, especially over long distances. As a result, the crocodaile effect—big mouth and small ears—is hyperactivated. Outwardly, it looks as if there is a bad (deaf) operator behind the transceiver. It can be assumed, that the best option Of all the possible - carry a spider or "Russian Robinson" with you ( this is not the same thing, as many assume).

The antennas are relatively light, with relatively good gain and the directional coefficient, which is actually not good, since working from the field and islands involves mainly working on CQ, and it is unknown from which direction the signal will come. It doesn’t take a sage to determine that even a three-element antenna has significant dips on the sides. Even Spider, not to mention Robinson, who strictly speaking is a hexabim, i.e. Its coefficient of performance and efficiency are higher than those of the Spider (of course, with the same dimensions). The fact is that hexabim elements are less curved and a larger part of their conductors than a spider’s is located in the plane of the “straight” element. Hence the large induced emf in the conductor. Plus, the deployment of such antennas is not such a simple process: a lot of vibrator wires, directors and reflectors, assembling a cross (or hexahedron), and you need to not mix anything up... Then pull all the elements up with guy wires to the same height and .d. ...
Thus, the priority properties of the desired field antenna are in the following order: equal reception and transmission efficiency, ease of assembly and installation, minimal SWR, preferably some kind of gain with a circular (or close to it) radiation pattern. The following proposal scores the most points - the W3DZZ panel stretched on fishing rods (for the design below) for the ranges of 14-28 MHz. If you stretch two such panels perpendicularly, they can be switched using a relay. Of the priorities, there are three and a half: gain = transmit, simple, SWR is close to 1, and, if there is no gain, then there is an almost directional action.
The thought naturally suggests itself of a two-element antenna with some kind of gain, but not such deep dips on the sides. And at the same time having a minimum SWR. Well, of course, easier to assemble, disassemble and install. After thinking, I decided to try the following design (working name - “garden-field”): four fishing rods in pairs, bent down by the required amount under the weight of the wire elements. This is good because it does not require special measures for centering, (determining the center of gravity) and hanging (pulling) the ends of the fishing rod up like in a spider. In order for the range elements to be parallel, for 10 and 15 meter elements you will have to use ropes - extend them to the clamp on the rod. The vibrator-director pair was chosen based on the fact that its gain is greater than that of the vibrator-reflector pair. Another argument is that the director is much shorter than the reflector. And this is the “wing span” of the antenna, weight, etc. One could be greedy and make the elements shortened with a capacitive load in the form of segments parallel to the traverse, but then the efficiency of the antenna and its already small gain will become even lower, and there will be a headache with calculating and stretching the elements of the capacitive load, so I abandoned this idea: that’s it It should be simple - sticks and wires. :-)
The advantages include: equal reception-transmission efficiency, good SWR, the presence of a small gain (4-4.5 dBd), which can be used if necessary, but most importantly - shallow dips on the sides - there is no need to constantly rotate the antenna. The simplicity of the design is obvious from the drawing, and those who dare to implement it in reality will appreciate the low material costs. Four thick-walled 6-meter fishing rods without the last knee and without rings cost 200 hryvnia at the market. It will take about the same amount to weld two fishing rod attachment points. If you don't know a welder, all the components can be assembled from wood using plywood and U-bolts. I don’t even know how much a dozen water clamps cost, hardly more than 10 hryvnia....
When assembled, the longest length is the length of the traverse - 1.95 m (for now). Thus, the antenna “package” does not exceed 2 meters in length. If the distance between the elements is not 5 cm, but 10 cm, the length of the traverse can be reduced to 1.45 m, but at the same time, for obvious reasons, the already small gain on the 20 meter range will decrease and increase on the 28 MHz range, but the antenna It will already be possible to transport it in the trunk of a Zhiguli. At the specified distance between elements, the antenna will theoretically have a gain of approximately 4-5 dBd (almost A3S Cushcraft). In practice, this value is unlikely to rise above 4-4.5 dBd. It is difficult to determine this exactly at home... :-) We say this in case someone wants to make one for themselves at the dacha. Of course, even if the diameter of the wires of the elements themselves is two millimeters, the antenna bandwidth will be very small, in the range of 100-150 kHz. By increasing the diameter of the wires, we increase the weight, and it is already large (for fishing rods :-). In fact, the thickness of the wire is no longer critical, since it is far beyond what is desired: make the elements with 1 mm wire and in practice nothing will change. Therefore, you need to be prepared for this and either change the size of the elements (CW or SSB sections) before raising the antenna, or put up with an increase in SWR at the edges of the range to an indecent value. The next problem that will arise due to the flexibility of fishing rods is a change in antenna parameters in gusty strong winds. It is clear that a strong wind will swing the ends of the fishing rods and, due to the fact that the voltage antinodes (resistance) are located exactly at the ends of the dipoles, the input impedance (read SWR) will change, which may lead to the launch of the transceiver’s autotuners. If such a problem arises, you can combat it by installing lightweight plastic water pipes as spacers between the fishing rods at a distance of no more than two meters from the traverse on each side. To fasten the spacers, you can use two clamps, as shown in the figure. It should be noted that this will most likely be needed only by those who wish to build this structure as a stationary one on the roof, since in order to “swing” fishing rods loaded with at least three wires, the wind must be very strong. A stretch garter with a regular nylon cord cannot be ruled out.
The rotating device itself is in the photo. Of course, other options cannot be ruled out: for example, a system of rope blocks or even a proprietary twist. But in the field, I think muscular strength is quite enough. The practice of using "Russian Robinson" has shown that wire yagi work perfectly at a height of 7 meters. Below, the strong influence of the earth begins and the resonance rapidly “moves” down. Thus, if you limit yourself to a height of 7 meters, you can get by with one level of stretch marks.
Thanks to Sergey, (UR5RMD), who calculated two versions of this design using MMANA-GAL Basic. You can get it here:http://gal-ana.de/basicmm/ru
Option one - just wires. It should be noted that many people have a critical attitude towards the strength of the structure: they claim that fishing rods will not withstand the weight of three wire elements for long. I tried to do something similar at the dacha, but with switching using a relay, a piece of wire that turned the director into a reflector. For one range it worked perfectly - as befits full-size 2nd elements, an increase (by ear) of about 2 points. As always, this parameter is important when the correspondent is barely audible in noise... :-) But as soon as the second range appeared, everything turned upside down. The director of the lower frequency range began to work as a reflector for the next one. Plus, there was nothing to calculate the distance between the elements at which this effect had minimal influence. Thus, my doubts concern the multi-range design.
Hence the confidence that the antenna should not be switched, but rotated. How, you ask? Easy, I’ll answer :-). The option is also military. At the bottom there is a pipe welded from below, in which there is a metal ball from a large bearing.The mast will turn on it(it is assumed that this is a set of one and a half meter pipes from an army prefabricated telescope, at the top there are two tiers of guy wires or on regular ones (reinforced so that they do not fall down the pipe)bearings, or, cooler,on support-radial. In practice, on expeditions, a support can be a stump with a hole hollowed out in the middle, a block, or even just a piece of board. The main thing is to ensure that the base remains motionless in the horizontal plane. As practice shows (see photo and comment below), muscular strength is quite enough. F(MHz) – frequency
R (Ohm) – antenna resistancejX (Ohm) – antenna reactance
SWR 50 – Standing wave ratio in a cable with a resistance of 50 Ohms.
Gh (dBd) – Antenna gain compared to a half-wave dipole
Ga (dBi) – Antenna gain relative to an isotropic radiator.
F/B (dB) – Forward/backward emission ratio.
Elev (gr) – Zenith angle (degrees) corresponding to the maximum gain.
Land – indicated during calculation (Free space, Ideal, Real)
Height – height on ideal, real ground.
Polar. – horizontal, vertical polarization.
Directional pattern at 20 meters. To save space, the diagrams for the 15 and 10 meter ranges are not shown, but you know that from range to range the “banana” stretches a little, and the dips on the sides slightly increase. The same thing happens with radiation in the vertical plane.


The dimensions of the elements and the distances between the elements are shown in the figures below. The distance between vibrators and directors is 1.95 meters. The vertical distance between elements is 5 centimeters. Vibrators
Directors. As we warned, the antenna is very narrowband. SWR varies greatly across bands. There is only one solution: choose the priority section - SSB or CW. Unfortunately. It must be said that both spider and hexabim suffer from the same disease. But they are literally used everywhere.


Tuning the antenna is quite simple and mostly requires patience: if we don’t need maximum back suppression, and we definitely don’t need it, then start tuning with the low-frequency ranges. First, adjust the 20-tube by changing the length of the vibrator to the minimum SWR, then change the length of the director to the minimum SWR and, if necessary, re-adjust the vibrator to the minimum SWR. Then the 15-meter range and at the end 10 m. I have already touched on this topic in my previous materials, take a look if you are not lazy... The biggest concern (and irritation) will be the tangle of wires and ropes. There is a way to reduce the number of elements several times - to make the antenna in two elements, but with ladders. Then each fishing rod will have one (heavy, admittedly) element that will work in three ranges. But the number of wires and ropes will decrease by 6 times. In addition, the length itself large element, the vibrator, will become smaller: 9 meters versus 11.6 meters for the full-size version. Worth a try? Of course, you will have to pay for everything; in this case, the antenna bandwidth will be narrowed even more. And structural elements other than straight wire will be added. The diagram of the new antenna version is shown in the figure below. To enlarge, simply click on the picture with the mouse.

The antenna characteristics are given in the table. Comparing the tables of parameters of both antennas, you can see that the gain of the antenna with ladders is slightly higher, but in practice these changes can be neglected, there will be no significant change in the radiation pattern, so we will only show the 20-meter range diagram, but the changes in SWR will be significant. The positive point is that the SWR value across the ranges will become smaller, of course, with precisely tuned traps, but a change in the SWR across the range can be very disappointing.

As for ladders, the recommendations are as follows. There are a sufficient number of programs on the Internet for calculating inductors for ladders. The capacitances in the ladders are not critical; you just need to take care of a sufficient (high) operating voltage of the capacitors in the case of large input power. At 100 watts, the operating voltage of the capacitors at 300 volts will be sufficient. The design also depends on how much power we will send to the antenna. Here is a link to one of the types of ladders http://dl2kq.de/soft/6-6.htm. And also “Three or more range dipoles with one pair of ladders” http://dl2kq.de/ant/kniga/533.htm. The trap antenna is configured as follows. First, you need to tune the circuits (trails) into resonance at a given frequency; it is most convenient to do this with the ramps already included in the antenna fabric using a heterodyne resonance indicator (HIR). It is clear that the resistance of the circuits will be high at the resonant frequency and thereby the electrical lengths of the antennas are adjusted. Then the wires are adjusted. We start with the 10 meter range. By changing the length of the vibrator, adjust the SWR to a minimum. Then, by changing the length of the director, we also achieve the minimum SWR reading. If the SWR does not satisfy us, then again we need to adjust the vibrator to the minimum SWR. Then we move on to 15 m and 20 m. With well-tuned ladders, this process will not be difficult and time-consuming. This way you have a choice of what to try - a standard 2 el 3 bander or a ladder design.
Comment and photo by R9HAJ (Rinat Kulakhmetyev): " Good day, I still couldn’t take a picture of the antenna... I’m happy so far as a locomotive, it withstood a hurricane, survived the winter, and works stably. The beam is slightly longer than calculated."

Based on the results of subsequent experiments, the Ogorodno Field Antenna 2 was created in which, due to the bending of the longest elements of the 20-meter range, it was possible to reduce the “wingspan” by as much as 2 meters and improve the strength (at least stability) of the elements. We had to pay for this with some deterioration in the radiation pattern. Best wishes Egor UY2RA.

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Here is a link to a very interesting resource on the Internet - http://tempsdr.suws.org.uk:82 We already know WEB SDR radio, but on UHF/VHF and with good sensitivity. You can listen to both local London skeds and local packet networks. For us, this is probably the most interesting thing - you can use “other people’s ears”, it’s true, but independently receive telemetry from all sorts of satellites that can be heard there in London. For example, I dug into their PR networks with interest. Although we should also try satellites. Let's do it together?