HF Antennas. shortwave antennas on amateur bands, is and remains one of the hot topics in amateur radio. The beginner looks at which antenna to use and the aces of the ether from time to time look at what's new. In order not to stand still, but to improve our results, here we are following this path, understanding and improving our antennas. You can even single out some radio amateurs in separate group- Antennas.
AT recent times antennas and ready-made have become more accessible. But, even having bought such an antenna along with the installation, the owner, in our case, a radio amateur, must have an idea. In my view, everything starts with the place where our antennas will be placed, then the antennas themselves. Of course, not everyone has the choice of a place, but here we can win great, and how to choose, not everyone has such a flair, but there are such radio amateurs.
HF Antennas First
Technically, it is problematic to compare the place on HF (on VHF it is simple and measurements show a difference of four decibels). May those who face such a choice of place be lucky. For HF bands, we have a larger selection of antennas and dimensions are tolerable, but for LF bands, the choice of antennas in finished form is smaller. Yes, and it’s understandable - not everyone can afford five elements of a yaga for a range of 80 meters. Here the field of work can be large if the radio amateur has such a field for placing antennas on the low bands
There is such a book where there is a lot of information on antennas for low frequency bands
Amateur antennas of short and ultrashort waves
The antenna is a device involved in the process of transferring electromagnetic energy from the power line to free space, and vice versa. Each antenna has an active element, such as a vibrator, and may also contain one or more passive elements. Active element antennas - - a vibrator, as a rule. directly connected to the power line. Appearance AC voltage on the vibrator is connected both with the propagation of the wave in the power line, and with the emergence of an electromagnetic field around the vibrator.
Ideal antenna for HF communications
What kind of antennas do we radio amateurs use. What do we need? Do we need an ideal antenna for meter bands. Say that there are none, and that nothing is perfect at all. Then close to perfect. What for? You ask. Who wants to achieve results, to go forward, he will sooner or later come to this issue. Let's look at how to understand the ideal antenna on the meter amateur bands. Why precisely on amateur meters, but because our correspondents are on different distances in different sides Sveta. Let us add here the local conditions where the antenna is located, and the conditions for the passage of radio waves in given time at these frequencies. There will be many unknowns. What angle of radiation, what polarization will be maximum in a specific period of time with a specific correspondent (territory).
Yes, some people might get lucky. With a place, choice of antennas, suspension height. So what should be done? To always be lucky. We need such an antenna, which at any time will have best parameters for a given passage of radio waves with any territory. More = We scan (twist) the antenna in azimuth, this is good. This is the first condition. The second condition = we need to scan along the radiation angle in the vertical plane. If anyone does not know - depending on the conditions of passage, the signal may come from different angles from the same correspondent. The third condition = is polarization. Scanning or changing polarization from horizontal to vertical polarization and vice versa, smoothly or stepwise. Having created and received these three conditions in one antenna, we get ideal antenna for amateur radio communication on short waves.
Ideal Antenna
Ideal Antenna so what is it. If we consider, for example satellite dishes, then perhaps it becomes clearer, easier to understand. Here we take the size (diameter of the dish), this is a direct dependence on the gain. One satellite - we took a 60cm antenna as an example. diameter. The signal level at the receiver input will be low, and sometimes we will not see the picture. Let's take an antenna with a diameter of 130 cm. The level is normal, the picture is stable. Now let's take an antenna with a diameter of 4 meters and what can we observe. Sometimes the picture disappears. Yes, there are two reasons for this. It was the wind that shook our 4-meter antenna and the signal disappeared. This satellite in orbit does not hold its coordinates stably. So it turns out, on the one hand, the 4-meter antenna is the best in terms of gain, on the other hand, it is not optimal, which means it is not ideal. In this case, the optimal antenna is 130 cm. In this case, why can't it be called ideal.
So it is on the meter amateur radio bands. Not always five elements of a yaga at a height of 40 meters for an 80-meter band will be optimal. So not ideal. You can even give a few examples from practice. In my laboratory work, I made 3 elements for a 10-meter range. Passive elements are bent inside the active. Then three - the band version of such an antenna will come into fashion under a well-known name. I listened, twisted and, of course, made connections to this antenna, the first impression was wonderful. Then the weekend came, another contest. But when I turned on the top 10 with this antenna, then silence, so I think yesterday the range rattled, but today there is no passage.
From time to time I turned on this range in order to listen, the passage would suddenly begin. At the next call to 10-ku, numerous amateur radio stations stunned me - it began. And then I immediately discover that the wrong antenna is connected. Instead of 3-elements, there was a pyramid for the 80-meter band. I switch to 3 elements - silence, signals thunder on the pyramid. I went outside, examined 3 elements, maybe something happened, no, everything is fine. Well then I worked on 28 megahertz, I made many connections on the pyramid for the 80-meter band. On Monday, Tuesday, the same picture was observed, and only on Wednesday it seemed to fall into place. There is silence on the pyramid, but on the 3-elements they rattle. What is the difference? The difference in the angle of radiation.
In my pyramid, the radiation is at 28 MHz. at an angle of 90 degrees, that is, at the zenith, and in a 3-element below 20 degrees. Such practical example gives us food for thought. Another example was when I was in the zero area. I hear a call for the zero region on the 20th, I know that this comrade has an antenna for several thousand dollars, that it is at a good height and the power amplifier there is not less than a kilowatt. I call him, but he does not hear, or rather, he hears, but he cannot even make out the call sign. He twisted his expensive antenna, there was no sense, and out loud he said, like, that there is no passage today. Here on this frequency I hear - and you receive me. Yes, I accept. It turned out to be his neighbor and with only five watts and the antenna is such that I have already forgotten (perhaps, like a triangle at 80). We made a radio contact, and he was pleasantly surprised, knowing what kind of antenna and power the neighbor had. I don’t know how many meters, kilometers between them, but in that case the steep antenna was powerless.
Antennas for low frequency bands
There were such laboratory works and on 40 and 80-meter bands. All this is in search of which antenna is better. And there is a moment here where radio amateurs still have the opportunity to work on such an antenna so that it is optimal at any time, and therefore ideal. In part, radio amateurs use some points that should be incorporated into an ideal antenna. The simplest is the azimuth adjustment. The second in terms of radiation angle - we put the same antennas on different masts, at different heights or at the same one, while switching them into stacks. We get different angles of radiation. And also different antennas with different polarization, some have. But this is partly, not in general. Yes, and some will say, why such an antenna. Ten kilowatts and the first place in your pocket. Yes, it's your choice. In this case, you deceive not only everyone, but first of all yourself. Or who has been using such an antenna for HF for a long time (there is one for VHF), where the properties of an ideal antenna are laid down.
Our Antennas
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For many radio amateurs, this topic has been, is and will be one of the most popular. Which antenna to choose, which one to buy. In either case, we need to mount it, install it, configure it, here we need some knowledge on antenna topics, magazines and books on antenna topics will help here. So that in the end we understand something. That the radio amateur's antenna should be one of the first lines. That SWR is not an indicator and you don’t have to chase it in the first place. That an antenna with SWR=2 can perform much better than one with SWR=1. That the efficiency drops with an increase in elements and much more.
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Log-periodic wire antenna for 40 meters. Everything is simple and effective. Several options for "sloper" antennas for low-frequency bands of 40,80,160 meters. Scanned antenna RA6AA, setup, parts used. In the magazine Radioamateur 1 1991. Read completely.
Practice tuning and mounting antennas. Mast lifting. Options for attaching antenna sheets to a tree. Tuning using a GSS and a tube voltmeter in the Radio Amateur 2 magazine 1991. Read.
In the seventh issue for 91 years of the magazine Radioamateur RA6AEG talks about his M antenna.
All this information is primarily for those who already have the call sign of an amateur radio station. Also for everyone else who has not yet come to HF.
Name: Amateur antennas of short and ultrashort waves.
An extensive range of issues is considered (the theory of antennas, power lines, radio wave propagation, etc.), the study of which will help to purposefully choose antenna circuits and its parameters for various ways amateur radio communications. Descriptions are made of the main types of amateur antennas, including their numerous modifications and recommendations for manufacturing and tuning.
For a wide range of radio amateurs.
In addition to purely antenna topics, the book discusses the theory of long lines, which helps to understand the theory of wire antennas and power lines, and outlines the design of baluns and matching devices (without which it is difficult to get good internal parameters antennas), provides basic information about the propagation of radio waves (without knowledge of which it is impossible to carry out right choice external parameters antennas).
The radio amateur is already familiar with a number of publications on the theory and technology of antennas (we note in passing that they are clearly not enough) and has the right to ask what new things will give him this book. It seems to us that we have already partially answered this question. Let us add that this book surpasses other well-known publications in terms of the variety of considered problems related to the design of amateur radio antennas, in terms of the number of antennas analyzed and the extremely large amount of calculated and experimental data.
Translation editor's preface
Chapter 1. Introduction
1.1. Amateur radio antenna devices
1.2. Classification of amateur radio antennas
Chapter 2. Elements of Antenna Theory
2.1. electromagnetic field
2.2. Power lines
2.3. Elements of Antenna Theory
Chapter 3 Antenna Power
3.1. Options for building power lines
3.2. Practical implementations of matching systems
3.3. Balancing devices
3.4. Coordination of the "transmitter-power line" system
Chapter 4
4.1. Introductory remarks
4.2. Methods of propagation of radio waves
4.3. Basic laws of radio wave propagation
4.4. Energy balance of radio links
Chapter 5 Short Wave Antennas
5.1. Introduction
5.2. Harmonic antennas
5.3. Aperiodic aitens
5.4. Dipole Antenna Systems
5.6. Dipole antennas of the "wave channel" type
5.6. Loop Antennas
5.7. Loop Antennas
5.8. Vertical dipoles
5.9. DDRR Antenna
Chapter 6
6.1. Introduction
6.2. VHF Dipole Antennas
6.3. Antennas surface wave
6.4. Antenna arrays
6.5. Antennas for satellite communications
6.6. Reflector antennas
6.7. Spiral aitens
6.8. Recommendations for radio amateurs
Applications
Bibliography
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I needed a transmit-receive antenna that would work on all HF and VHF bands and at the same time it did not need to be rebuilt and coordinated. The antenna should not have strict dimensions and should work in all conditions.
Recently, I have FT-857D at home, this (like many others) The transceiver does not have a tuner. They don’t let you on the roof, but you want to work on the air, so from the loggia, I lowered a piece of wire at an angle of 50 degrees, the length of which I didn’t even measure, but judging by the resonant frequency of 5.3 MHz, the length is about 14 meters. At first, I made different matching devices for this piece, everything worked and matched as usual, but it was inconvenient to run from the room to the loggia to tune the antenna to the desired range. Yes, and the noise level at 7.0, 3.6 and 1.9 MHz reached 7 points on the S-meter (high-rise building, near the main street and a bunch of wires). Then the idea came to make an antenna that would make less noise and it did not need to be rebuilt in ranges. Of course, this will slightly reduce efficiency.
Initially I liked the idea of TTFD, but it is heavy, too noticeable, and a piece of wire was already hanging (don't take it off). In general, taking the principle of this antenna as a basis, I slightly changed its connection, and you can see what came of it in the picture. As a 50 ohm non-inductive resistor, an equivalent rated for 100 W of power is used. The counterweight is a piece of wire 5 meters long, which is laid along the perimeter of the loggia. I think that a few resonant balances will improve the performance of this antenna for transmission (however, like any other pin). Cable RK-50-11 goes to the radio station and has a length of about seven meters. 
When this antenna is connected to a radio station, the air noise is reduced by 3 - 5 divisions on the S-meter, compared to the resonant one. Useful signals also fall slightly in level, but they are heard better. For transmission, the antenna has a SWR of 1:1 in the range of 1.5 - 450 MHz, so now I use it to work on all HF / VHF bands with a power of 100W. and everyone I hear answers me.
To make sure that the antenna works, I did some experiments. To start, I made two individual connections to the beam. The first is a shortening capacitance, which results in an elongated 7 MHz pin, which is perfectly matched and has an SWR = 1.0. The second is the broadband version described here with a resistor. Thus, I had the opportunity to quickly switch matching devices. Then I chose weak stations at 7 MHz, usually they were DL, IW, ON ... and listened to them, periodically changing matching devices. The reception was approximately the same, on both antennas, but in the broadband version, the noise level was much less, which subjectively improved the audibility of weak signals.
A comparison between an extended pole and a broadband antenna, for transmission in the 7MHz band, gave the following results:
.... connection with RW4CN: for extended GP 59+5, for broadband 58-59 (distance 1000km)
....communication with RA6FC: for extended GP 59+10, for broadband 59 (distance 3km)
As you might expect, a broadband antenna loses out to a resonant transmission. However, the loss is small, and with increasing frequency it will be even smaller, and in many cases it can be neglected. But the antenna really works in a continuous and very wide range frequencies.
Due to the fact that the length of the radiating element is 14 meters, the antenna is really effective only up to 7 MHz, in the 3.6 MHz band many stations hear me poorly or do not answer at all, only local QSOs are possible on 1.9 MHz. At the same time, from 7 MHz and above, there are no problems with communication. Audibility is excellent, everyone responds, including DX, expeditions and all sorts of mobile radio stations. On VHF, I open all local repeaters and conduct FM QSOs, although 430 MHz is greatly affected horizontal polarization antennas.
This antenna can be used as the main, spare, receiving, emergency and anti-noise in order to better hear remote stations in the city. By placing it like a pin or by making a dipole, the results will be even better. You can ""turn"" into a broadband, any antenna already installed earlier (dipole or pin) and experiment with it, you only need to add a load resistor. Note that the length of the arm of the dipole or the length of the rod web does not matter, since the antenna has no resonances. The length of the canvas, in this case, only affects the efficiency. Attempts to calculate the characteristics of the antenna in MMANA failed. Apparently, the program cannot correctly calculate this type of antenna, this is indirectly confirmed by the TTFD calculation file, the results of which are very doubtful.
I haven't checked yet, but I'm guessing (similar to TTFD) that to increase the efficiency of the antenna, you need to add several resonant balances, increase the beam length to 20 - 40 meters or more (if you are interested in the 1.9 and 3.6 MHz bands).
Transformer option
Having worked on all HF-VHF bands on the option described above, I slightly redid the design by adding a 1: 9 transformer and a 450 ohm load resistor. Theoretically, the efficiency of the antenna should become greater. Changes in design and connection, you see in the picture. When measuring the uniformity of the overlap, with the MFJ device, a blockage was visible at frequencies from 15 MHz and higher (this is due to the unsuccessful brand of the ferrite ring), with a real antenna, this blockage remained, but the SWR was within the normal range. From 1.8 to 14 MHz SWR 1.0, from 14 to 28 MHz it gradually increased to 2.0. On the VHF bands, this option does not work, due to the high SWR.
Testing the antenna in real air gave the following results: Air noise during the transition from extended GP to broadband antenna, decreased from 6-8 points to 5-7 points. When working on a transmission with a power of 60W, in the 7MHz band, the following reports were received:
RA3RJL, 59+ wideband, 59+ remote GP
UA3DCT, 56 wideband, 59 remote GP
RK4HQ, 55-57 wideband, 58-59 remote GP
RN4HDN, 55 wideband, 57 remote GP
On the F6BQU page, at the very bottom, a similar antenna with a terminating resistor is described. Article in French. So the goal is achieved, I made an antenna that works on all HF and VHF bands, which does not require coordination. Now you can work on the air and listen to it while lying on the couch, and switch bands only with the button on the radio station. Laziness rules the world. hee. Submit your feedback....
Option number three
I tried another option, broadband antenna matching. This is a classic 1:9 unbalanced transformer loaded with a 450 ohm resistor on one side and a 50 ohm cable on the other. The length of the beam does not really matter, but unlike the previous design, it is important that it does not fall into resonance on any amateur band. (for example 23 or 12 meters). then the SWR will be good everywhere. The transformer is wound on a ferrite ring, with three wires folded together, I got 5 turns, which must be evenly spaced around the circumference of the ring.
The load resistor can be made composite, for example, 15 pieces of 6k8 resistors of the MLT-2 type, will provide you with the opportunity to work in CW and SSB with a power of up to 100W. As grounding, you can use a beam of any length, water pipes, a stake driven into the ground, etc. Finished construction is placed in a box from which there is a PL connector for the cable and two terminals for the beam and ground. Operating frequency range 1.6 - 31 MHz.
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