HF antennas. Ultra-wideband antenna for operation on all HF and VHF bands
I needed a transceiver antenna that would work on all HF and VHF bands and did not need to be rebuilt and coordinated. The antenna should not have strict dimensions and should work in any conditions.
Recently, I have an FT-857D at home, this one has (like many others) The transceiver does not have a tuner. They are not allowed on the roof, but I 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 did not even measure, but judging by the resonant frequency of 5.3 MHz, the length is approximately 14 meters. At first, I made different matching devices for this piece, everything worked and coordinated as usual, but it was inconvenient to run from the room to the loggia to adjust the antenna to the desired range. And the noise level at 7.0, 3.6 and 1.9 MHz reached 7 points on the S-meter (multi-storey building, near the main street and a lot of wires). Then the idea came to make an antenna that would make less noise and would not need to be adjusted according to bands. Of course, this will reduce the efficiency slightly.
Initially I liked the idea of TTFD, but it was 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 out of it in the picture. An equivalent rated at 100W of power is used as a 50-ohm non-inductive resistor. The counterweight is a piece of wire 5 meters long, which is laid around the perimeter of the loggia. I think that several resonant counterweights will improve the transmission performance of this antenna (just like any other pin). The RK-50-11 cable goes to the radio station and is about seven meters long. 
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 drop slightly in level, but you can hear them better. For transmission, the antenna has an 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 100 W. and everyone I hear answers me.
To make sure that the antenna works, I conducted several experiments. To begin with I made two separate connections to the beam. The first is a shortening capacitance, with it we get an extended pin at 7 MHz, which matches perfectly and has an SWR = 1.0. The second is the broadband version described here with a resistor. This gave me the opportunity to quickly switch matching devices. Then I selected weak stations on 7 MHz, usually DL, IW, ON... and listened to them, periodically changing matching devices. Reception was approximately the same on both antennas, but in the broadband version, the noise level was significantly lower, which subjectively improved the audibility of weak signals.
A comparison between an extended rod and a wideband antenna, transmitting in the 7 MHz range, gave the following results:
....communication 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 would expect, the broadband antenna loses on resonant transmission. However, the magnitude of 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 frequency range.
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 range, many stations hear me poorly or do not respond at all; at 1.9 MHz only local QSOs are possible. At the same time, from 7 MHz and above there are no problems with communication. The audibility is excellent, everyone responds, including DX, expeditions and all sorts of mobile r/stations. On VHF, I open all local repeaters and conduct FM QSO, although at 430 MHz the horizontal polarization of the antenna greatly affects it.
This antenna can be used as a main, backup, receiving, emergency and anti-noise antenna to better hear remote stations in the city. By placing it like a pin or 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 just need to add a load resistor. Please note that the length of the dipole arm or the length of the pin blade does not matter, since the antenna has no resonances. Length of the canvas, in in this case only affects efficiency. Attempts to calculate the antenna characteristics in MMANA failed. Apparently, the program cannot correctly calculate this type of antennas; 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 counterweights, increase the beam length to 20 - 40 meters or more (if you are interested in the 1.9 and 3.6 MHz bands).
Option with transformer
Having worked on all HF-VHF bands using the option described above, I slightly redesigned the design by adding a 1:9 transformer and a 450-ohm load resistor. Theoretically, the efficiency of the antenna should increase. Changes in design and connections, you see in the figure. When measuring the uniformity of overlap using the MFJ device, a blockage was visible at frequencies of 15 MHz and higher (this is due to the unsuccessful brand of ferrite ring), with a real antenna this blockage remained, but the SWR was within normal limits. From 1.8 to 14 MHz SWR 1.0, from 14 to 28 MHz it gradually increased to 2.0. On VHF bands, this option does not work due to the high SWR.
Testing the antenna on the air gave the following results: The air noise when switching from an extended GP to a broadband antenna decreased from 6-8 points to 5-7 points. When working with a transmission power of 60W, in the 7MHz range, the following reports were received:
RA3RJL, 59+ wideband, 59+ remote GP
UA3DCT, 56 wideband, 59 remote GP
RK4HQ, 55-57 broadband, 58-59 remote GP
RN4HDN, 55 broadband, 57 remote GP
On page F6BQU, at the very bottom, a similar antenna with a load resistor is described. Article in French. So the goal has been achieved, I made an antenna that works on all HF and VHF bands and 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 a button on the radio station. Laziness rules the world. hee. Send 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 is not particularly important, but unlike the previous design, it is important that it does not resonate 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 need to 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 ability 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. The finished structure is placed in a box from which comes a PL connector for the cable and two terminals for the beam and grounding. Operating frequency range 1.6 - 31 MHz.
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 broadcast aces from time to time look at what’s new. In order not to stand still, but to improve our results, we are following this path of understanding and improving our antennas. It is even possible to single out some radio amateurs as separate group- Antenna operators.
IN Lately antennas and finished form have become more accessible. But even having purchased such an antenna along with the installation, the owner, in our case the radio amateur, should have an idea. In my opinion, everything starts with the place where our antennas will be placed, then the antennas themselves. Of course, not everyone is given the choice of place, but here we can win big, and how to choose, not everyone is given such an instinct, but there are such radio amateurs.
HF Antennas come first
Technically, comparing a location on HF is problematic (on VHF it’s easy and measurements show a difference of four decibels). Let those who have to choose such a place be lucky. For the HF bands we have a larger selection of antennas and the dimensions are tolerable, but for the LF bands the choice of ready-made antennas is smaller. And it’s clear that not everyone can afford five yagi elements for the 80-meter range. This is where the field of work can be large, if a radio amateur has such a field for placing antennas in the low frequency ranges
There is a book with a lot of information on antennas for low frequency bands
Amateur antennas of short and ultrashort waves
An antenna is a device involved in the process of transmitting 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. The active element of the antenna is, as a rule, a vibrator. directly connected to the power line. Appearance AC voltage on the vibrator is associated both with the propagation of the wave in the power line and with the occurrence electromagnetic field around the vibrator.
Ideal antenna for amateur radio communications on HF
What antennas do we, radio amateurs, use? Which ones do we need? Do we need an ideal antenna for meter bands? Say that there are no such people, and that nothing is perfect at all. Then close to ideal. What for? You ask. Anyone who wants to achieve results and move forward will sooner or later come to this question. Let's look at how to understand an ideal antenna on the meter amateur bands. Why on amateur meter, and because our correspondents are on different distances V different sides Sveta. Let's 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 a lot of unknowns. What angle of radiation, what polarization will be maximum in a specific period of time with a specific correspondent (territory).
Yes, some may get lucky. With location, choice of antennas, height of suspension. So what should you do? To always be lucky. We need an antenna that will have best parameters For of this walkthrough radio waves with any territory. More details = We scan (rotate) the antenna in azimuth, this is good. This is the first condition. Second condition = we need to scan along the radiation angle in the vertical plane. If anyone doesn’t know, depending on the transmission conditions, the signal can arrive at different angles from the same correspondent. The third condition = is polarization. Scanning or changing polarization from horizontal to vertical polarization and back, smoothly or stepwise. By creating and obtaining these three conditions in one antenna, we get ideal antenna for amateur radio communications on short waves.
Ideal antenna
Ideal antenna, so what is it. If we consider, for example satellite dishes, then perhaps it becomes clearer and easier to understand. Here we take the size (diameter of the plate), 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 could be two reasons. It was the wind that shook our 4-meter antenna and the signal disappeared. This satellite in orbit does not maintain its coordinates stably. So, on the one hand, it turns out that the 4-meter antenna is the best in terms of gain, but 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. Five yagi elements at a height of 40 meters for the 80-meter range will not always be optimal. So, not ideal. You can even give some examples from practice. In my laboratory work I made 3 elements for the 10-meter range. Passive elements are curved inward of the active one. Then a three-band version of such an antenna will come into fashion under the well-known name. I listened, twirled it, and of course made connections to this antenna, the first impression was wonderful. Then the weekend came, another contest. But when I turned on 10 with this antenna, there was silence, so I think, yesterday the range thundered, but today there is no passage.
From time to time I turned on this range to listen in case a passage suddenly began. During the next approach to 10, numerous amateur radio stations deafened 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 range. I switch to 3 elements - silence, signals are blaring on the pyramid. I went outside, examined 3 elements, maybe something happened, no, everything is fine. Well, then I worked on 28 megahertz, made a lot of connections to the pyramid for the 80-meter range. On Monday and Tuesday the same picture was observed, and only on Wednesday things seemed to fall into place. There is silence on the pyramid, but on the 3-element there is noise. What is the difference? Difference in radiation angle.
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 one below 20 degrees. Such practical example gives us something to think about. Another example was when I was in the zero area. I hear a call on the 20 for the zero region, I know that this friend has an antenna for several thousand dollars, that it is at a good height and the power amplifier there is no less than a kilowatt. I call him, but he doesn’t hear, or rather, he hears, but he can’t even make out the call sign. He twisted his expensive antenna, to no avail, and he said out loud that there was no way through today. Here on this frequency I hear - and you receive me. Yes, I accept. It turned out that his neighbor had only five watts and the antenna was such that I had already forgotten (perhaps like a triangle at 80). We made radio contact, and he was pleasantly surprised, knowing what antenna and power his neighbor had. I don’t know how many meters or kilometers there are between them, but in that case the cool antenna was powerless.
Antennas for low frequency ranges
There were such laboratory works both on the 40 and 80 meter bands. All this is in search of which antenna is better. And there is a point 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 included in an ideal antenna. The simplest thing is to set it in azimuth. The second in terms of radiation angle is to place identical antennas on different masts, at different heights or on the same one, while switching them into stacks. We get different radiation angles. And also different antennas with different polarization, some have. But this is partly, not overall. And some will say, why such an antenna? Ten kilowatts and first place in your pocket. Yes, it's your choice. At the same time, you are deceiving not only everyone, but first of all yourself. Or who has been using such an antenna for a long time on HF (there is one on VHF), where the properties of an ideal antenna are inherent.
Our antennas
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For many radio amateurs, this topic was, is and will be one of the most popular. Which antenna to choose, which one to buy. In both cases, 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 antenna of a radio amateur should be one of the first lines. That SWR is not an indicator and there is no need to chase after it in the first place. That an antenna with SWR=2 can work much better than with SWR=1. That efficiency decreases with increasing elements and much more.
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Log-periodic wire antenna for the 40 meter range. Everything is simple and effective. Several variants of “sloper” antennas for low-frequency bands of 40,80,160 meters. Scanning antenna RA6AA, setup, parts used. In the magazine Radio Amateur 1 1991. Read in full.
Practice tuning and installing antennas. Raising the mast. Options for attaching antenna panels to wood. Tuning using GSS and a tube voltmeter in the magazine Radio Amateur 2 1991. Read.
In the seventh issue for 91 years of Radio Amateur magazine RA6AEG talks about its 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.
Antenna for amateur radio communications
The antenna device consists of an antenna and a feed line that serves to transmit RF energy from the transmitter to the antenna and from the antenna to the receiver.
To a large extent, the efficiency of the antenna is determined by the properties of the feed line, and therefore, when designing an antenna device, the most serious attention should be paid to the implementation of the feed line. The main requirements for feeder lines are to ensure minimal losses, that is, high efficiency, and the inadmissibility of distortion of the directional properties of the antenna.
To transfer energy high frequency with the highest efficiency, it is necessary to ensure that energy moves along the feeder in only one direction, for example, from the transmitter to the antenna. In this case, only so-called traveling waves will propagate in the feeder.
The specified mode is ensured if the load resistance is equal to the characteristic impedance of the feeder, the value of which is usually indicated in reference books. In this case, the traveling wave coefficient KBV (Kb), which is determined by the formula:
Kb = Zv/Rn,
where Zв is the characteristic impedance of the feeder, and Rн is the input impedance of the antenna, equal to 1. In some cases, measurements are carried out not in units of KBV, but in units of standing wave ratio - SWR (Ks).
Ks = 1/Kb.
When determining efficiency feeder formula is used:
where B is the attenuation constant, which, in the case of using a coaxial cable as a feeder, can be taken from a reference book, L is the length of the feeder. The efficiency for the most commonly used values of the product BL can also be determined from the graph Fig.1.
Fig.1
In amateur radio conditions, when correspondents are located at different distances and in different directions, it is most convenient to use vertically located antennas with a circular radiation pattern in the horizontal plane. However, on the 80 m band, a vertical quarter-wave vibrator is structurally difficult to construct.
A half-wave vibrator located parallel to the ground has two radiation maxima in directions perpendicular to the antenna axis, and there is no reception or radiation along the axis. To avoid this drawback, in some cases, two horizontal antennas are installed, located perpendicular to each other and switched depending on the direction towards the correspondent. Installation of such antennas requires several masts, which is structurally inconvenient.
Behind last years The antenna became widespread among Soviet and foreign radio amateurs Inverted Vee. To operate on the 80 and 40 m bands, this antenna consists of two half-wave vibrators (dipoles) connected in parallel. The antenna is powered using an unbalanced coaxial cable.
When feeding balanced antennas with an unbalanced cable, a balanced device is usually used. In this design, the center conductor of the cable is connected to one arm of the dipole, and the braid to the other. As a result of such inclusion, the equality of the capacitances of the halves of the vibrator with respect to the ground is violated, therefore the currents in the halves of the vibrator will be different, and an equalizing current will flow along the outside of the outer braid. It will create an external radiation field, which in this case is useful, since it provides circular radiation.
Due to the inclination of the wires of the canvas to the ground at an angle of 45 degrees, it emits both horizontally and vertically polarized waves.
The radiation patterns for two components in the horizontal plane look like figure eights, rotated 90 degrees relative to each other. As a result of this, and also due to the radiation of the feeder, the antenna radiates energy in the horizontal plane at all angles. The antenna design is simple and understandable from Fig.2.
Fig.2. Inverted Vee Antenna Design
To install the antenna, you only need one mast, which can be mounted on the ground or on the roof of the house. The mast can be made of duralumin or steel pipes with a diameter of 50...60 mm, as well as wood. It is secured using two tiers of guy wires.
Walnut insulators are inserted into the guys of the lower tier every 4...5 meters in order not to introduce distortions into the radiation diagram. The top tier of guys are the vibrators themselves. The planes of the vibrators of the 40 m and 80 m ranges must be located perpendicular to each other. For vibrators, copper wire with a diameter of 2.5...3 mm or bimetallic with a copper top layer is used. For the lower tier of guy wires, steel wire or cable is used. Vibrators are attached to the top of the mast through separating insulators.
The central conductor of a coaxial cable with a characteristic impedance of 50 Ohms (RK-50-3-13, etc.) is connected to vibrators “a” and “b”. As a last resort, you can use a cable with a characteristic impedance of 60 Ohms (RKG-5, RKS-5).
The cable braid is connected to vibrators “b” and “d”. It should be remembered that the electrical contact must be reliable. It is best to solder the connection points and protect them with insulating tape (or varnish) to protect them from atmospheric influences. Coaxial cable laid inside the mast or mounted on its surface.
After manufacturing the antenna, it is necessary to determine the efficiency. feeder according to the above formula or according to the schedule Fig.1. To do this, the SWR value can be approximately measured, for example, using a device published in the journal Radio No. 6/1978 p.20.
If all antenna dimensions are observed, the feeder SWR should be close to unity, and the efficiency should be feeder to be 85...90%. At low efficiency It is necessary to improve the matching of the feeder with the antenna by changing the length of the vibrator of the range on which the measurement is made.
Eng. Yu. Zhomov (UA3FG), master of sports of the USSR. "Radio" No. 4/1968
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