There is always a good discussion to be had on what types of antenna perform the best under given circumstances. For some the choice may be a large directive antenna on a high tower, but for most radio amateurs space and many other restrictions mean that compromises have to be made. When there are restrictions the challenge is to adopt the best form of antenna for the particular location.
This can often lead to some experimentation which is normally very interesting and leads to a much better understanding of the operation of antenna systems and two way radio communication in general. There are many options for amateur radio antennas that can be taken, some simple, some that can be made, some that are bought.
Some of the very many options for antennas are given below. The end fed wire, often called a long wire antenna is one of the simplest to build and install.
Simply it consists of a length of wire that is connected to the receiver or transmitter. Often this type of antenna is called a long wire antenna, although a true long wire antenna is many wavelengths long, rather than a random length, often only less than a wavelength.
The more correct terminology is an end fed wire. Erecting this type of ham radio antenna is quite straightforward. A typical antenna installation is shown in the diagram, but it can be almost any suitable configuration. An antenna tuning unit will be required - one which can interface to an end fed wire. This is placed between the transmitter or receiver and the antenna wire. If one is not used, then the impedance of the antenna will not match that of the receiver or transmitter input and this will result in lower efficiency.
Also the transmitter may have trouble matching to this, and this may result in lower power output, or even damage to the transmitter output. It is also necessary to have a good earth connection.
What are the Different Antenna Types?
This should not just be the mains earth that the rig or power supply uses - this would not provide a good RF earth connection and it can result in interference to other electrical and electronic items. It is often thought that an end fed wire should be a quarter wavelength long on the major band of use.
This presents a low impedance to the radio and enables it to be matched very easily. However the current maximum which gives rise to the radiation occurs around this area and this means that there is lots of pick-up and radiation near the radio. This is not good as it results in local pick-up of noise etc and this can mask the wanted signals. Also for transmitters, lots of radiation occurs near the radio and this can cause interference to many other problems with electrical and electronic items.
Even if the antenna is not a quarter wavelength long, some pick up and radiation will occur near the radio and this is not good. If the antenna is not an odd multiple of quarter wavelengths long, then it can be difficult to match. Although the end fed wire can seem like a good option for amateur radio communication applications, it does have some drawbacks and may not provide the optimum overall performance. One popular antenna that is being used increasingly is known as the end fed half wave antenna, or EFHW antenna.
This type of wire antenna is a half wavelength long at its lowest frequency. Being a ham radio antenna, the many of the higher frequency bands are harmonically related, and therefore it will perform as a multiple number of half wavelengths on these bands.
Values of are widely used for these end fed half wave antennas, but some designs may even use ratios of up to - this equates to a turns ratio of around or The RF transformer used is referred to as an unun as it matches from an unbalanced line to an unbalanced antenna - the more familiar balun goes from balanced to unbalanced. Being a high impedance antenna an earth connection is not needed.In radio systems, many different antenna types are used with specialized properties for particular applications.
Antennas can be classified in various ways. The list below groups together antennas under common operating principles, following the way antennas are classified in many engineering textbooks. The dipole, monopole, array and large loop antenna types below typically function as resonant antennas; waves of current and voltage bounce back and forth between the ends, creating standing waves along the elements.
Aperture antennas can be resonant or not. Traveling wave antennas are nonresonant types, the current and voltage waves travel in one direction along the antenna elements. An isotropic antenna isotropic radiator is a hypothetical antenna that radiates equal signal power in all directions.
It is a mathematical model that is used as the base of comparison to calculate the directionality or gain of real antennas. No real antenna can have an isotropic radiation patternbut the isotropic radiation pattern serves as reference for comparing the radiation intensity of other antennas, regardless of type.
An "isotropic antenna" should not be confused with an " omnidirectional antenna "; an isotropic antenna radiates equal power in all three dimensions, while an omnidirectional antenna radiates equal power in all horizontal directions, with the power radiated varying with elevation angle, but decreasing to zero along the antenna's vertical axis. Nearly isotropic antennas can be constructed using multiple small elements, and are used as reference antennas for testing other antennas and for field strength measurements, and for backup antennas on satellites which work without the satellite being oriented towards a communication station.
Has circular polarization. The dipole is the prototypical antenna on which a large class of antennas are based. A basic dipole antenna consists of two conductors usually metal rods or wires arranged symmetrically, with one side of the balanced feedline from the transmitter or receiver attached to each.
This antenna radiates maximally in directions perpendicular to the antenna's axis, giving it a small directive gain of 2. Although half-wave dipoles are used alone as omnidirectional antennas, they are also a building block of many other more complicated directional antennas. Mast radiator antenna of medium wave AM radio station, Germany. Folded unipole with skirt wires connected at a midpoint on the tower.
A monopole antenna consists of a single conductor such as a metal rod, usually mounted over the ground or an artificial conducting surface a so-called ground plane. The radio waves reflected from the ground plane seem to come from an image antenna below the ground, with the monopole and its image forming a dipole, so the monopole antenna has a radiation pattern identical to the top half of the pattern of a similar dipole antenna.
The most common form is the quarter-wave monopole which is one-quarter of a wavelength long and has a gain of 5. Monopoles have an omnidirectional radiation patternso they are used for broad coverage of an area, and have vertical polarization.
The ground waves used for broadcasting at low frequencies must be vertically polarized, so large vertical monopole antennas are used for broadcasting in the MF, LF, and VLF bands.Recently a student in our Technician License Class realized that it may take quite a few antennas to cover all of the available ham bands.
This is a very valid question. Radio amateurs have so many bands available to them, it does present a challenge to figure out the antenna situation. The focus of this article is broader than that, with the addition of HF operation. The General Class license provides greatly expanded privileges on HF. These antennas are vertically polarized, covering basic 2m and 70 cm simplex and repeater operating.
Some folks may argue for just putting up a single-band antenna for 2m only, which is the most popular VHF band. You could put up single-band antennas for every band, but that gets complicated and typically results lots of antennas and lots of cable runs back to the ham shack. Focusing on the new ham, it makes sense to go for a multiband antenna and keep the number of individual coaxial cable runs to just a couple. My biases are towards the higher bands 20m and up because I like to work other countries around the world during daylight hours.
If you are more interested in North American contacts, especially in the evening hours, you might want to cover the 40m and 80m bands. For a new ham, this may be difficult to figure out, until you get some experience and discover your preferred ham bands. Some reasonably inexpensive commercial options with such band allowances are readily available as horizontal wire fan dipoles or trap dipoles. Fan Dipole also known as a parallel dipole — This is a half-wave dipole with additional elements added to cover additional bands.
While there is some interaction between the different dipole elements, they are normally fed by a common coaxial cable, avoiding the need for multiple cable runs. A fan dipole configures multiple dipoles trimmed to different bands using a single feedline. Not to scale. The dipole length is determined by the lowest frequency band and the traps are used to electrically shorten the dipole for higher bands. A trap antenna has resonant circuits inserted in the radiating element that electrically shorten the antenna for use at higher frequencies.
A well designed matching transformer at the end feed point facilitates this antenna configuration. Multiband versions of this antenna exist and are a convenient way to enable several bands at once. It is 65 feet long, uses three short stub extensions along the length, and has an end-of-wire feed point transformer with coaxial connector.
Multiband vertical — Quite a few different vertical antenna designs support multiple bands. When considering a vertical antenna, pay attention to whether the design requires ground radials to be installed.Getting started on DXing? Love to find and communicate with new people from distant locations? We researched and reviewed some of the best vertical HF antennas that will satisfy your hunger for DXing.
Things can get pretty much technical when you are looking to buy anything related to radio. We tried to keep things simple so that even new radio enthusiasts can understand.
Most of these antennas are portable and can be carried to new places. So, you get a bit of flexibility with them. The antenna is fully collapsible. It can be stretched from just 12 inches to 12ft. And the tripod can also be collapsed to 24 inches size. However, to access the lower ends of the HF bands from 3. Tuning is very easy in this antenna, thanks to the aircraft-grade aluminum tubular slide and military-grade slip connections. Apart from the antenna whip and tripod, you also get a radial set, ground mount, SWR ruler and a portable carrying bag.
The portability and the ability to communicate on HF and VHF bands is what makes the antenna worth buying. For HF, it operates on 3. On the higher end, it covers 7 to 30 MHZ. But for 2m, you will have to use an external adapter like the MC2 Superplexer. The antenna collapses from 7ft to 12 inches. And with an overall weight of 5 pounds, you can carry this kit anywhere you go.
We really loved the SuperMount clamp which you can use to attach the antenna to virtually anything from fences to plastic pipes. The best performance of this antenna can be found on 20M and above. The performance is similar to the large vertical HFs that are more expensive. If you want better performance than the MP1 we reviewed earlier, you should definitely get this one.
However, it might be a bit on the expensive side.
So, the price should be a factor here. The ability to perform exceptionally above 20M range is what makes this vertical HF antenna so effective. If you are searching for the best HF vertical antenna with no radials, then the Comet vertical antenna is worth installing. This is not a portable HF antenna. Because the fitting will become loose on each installation.
If you wanted something temporary, this is not the antenna to deal with. This is a multiband HF antenna for 3. So, no VHF here. It will readily provide SWR of 1. And the coax lead in the wire helps it to operate without radials. If you decide to add more radials, the performance will significantly improve. The only issue we found is that the antenna becomes ineffective below 15 ft.
So, you need to set it up at least above 16 ft and for best performance above 35 ft from the ground. The wind resistance of the antenna is good enough to withstand 67 MPH wind.Learn something new every day More Info An antenna, or aerial, is a device to send or receive signals. There are many antenna types and many ways of categorizing them. The two major antenna types that we first learn about and many people learn to distinguish as children are the antennae that are a body part for some animals on the one hand, as distinguished from all the antenna types that are made by people on the other hand.
Many people are familiar with insect antennae, but crustaceans—including the lobster—and myriapods have them, too. For animals, antennae function as a sensory organ.Amateur General Lesson 7.1B, Antenna Basics (G27B)
Antennas made by people are often metal and have many different designs. The second major categorical division of antenna types is between those that transmit signals, known as a transmitting antennas, and those that receive signals, called receiving antennas.
It is also possible to have antennas that are made to both transmit and receive. Usually, transmitting antennas handle a good deal more electrical energy than receiving antennas. Antenna types can also be used to differentiate antennas for radio, television, and radar systems. Because antennas can be built for transmission of different frequencies, another way to categorize antenna types is by their frequency.
The range of antennas can be categorized as short, medium, or long. For customers buying a television antenna, the decision is dependent on how close they are to the transmitting towers that they wish to pick up a signal from.
If the range is well matched to the distance, it will help avoid the antenna picking up unwanted signals. Location is another way of looking at antenna type. Antennas can be made for indoor installation, outdoor installation, or attic installation.
Indoor antennas are easy to install, but usually do not have the elevation to provide the best signal, particularly for customers who are far from the transmission. It used to be that outdoor antennas were primarily made for rooftops, but more are being designed to mount on the side of a house, or on a pole or deck.
The attic can be a useful installation point for those who do not want their antenna inside or outside for aesthetic or other reasons. Another set of antenna types is differentiated by style.
Best overall HF wire antenna
Style can speak to the antennas appearance in terms of design. It can also address whether the antenna is directional and gather signals from a central location or whether it is multidirectional, seeking signals from towers transmitting from different locations. I never realized there were so many different kinds of antennas. I thought I'd just go out and pick up a small one to place on top of my TV.Forgot Password?
The feed line also called the transmission line is the RF power conduit between your radio and your antenna. All the energy you generate travels to the antenna through the feed line. By the same token, all the signals picked up by your antenna must reach your radio through the same feed line. To complicate matters, all feed lines are not created equal.
The amount of loss at any frequency will vary considerably from one type of feed line to another. The most common type of feed line is coaxial cableor simply coax. There is also insulating material between the center conductor and the shield. This material can be hard plastic, foam plastic or even air. A popular type of feed line for HF use is ladder line. In fact, at HF frequencies it is the most common feed line for random-length dipoles and other antenna designs.
Ladder line consists of nothing more than two wires in parallel separated by insulating material. Just remember that the higher the decibel number, the greater the loss. Feed lines also have a characteristic impedance value measured in ohms. Coaxial cable commonly used for Amateur Radio has an impedance of 50 ohms while ladder line impedances can vary from to ohms. Amateur Radio transceivers are designed to work with an impedance of 50 ohms, so you must use 50 ohm coax, or find a way to convert the to ohm impedance of ladder line to 50 ohms.
If you are using an antenna that is designed to deliver a ohm impedance, it is best to use a coaxial feed line to provide a ohm antenna system impedance for your transceiver.
The other approach is to use a device called an antenna tuner to transform the impedance of the antenna system to 50 ohms for your radio without physically adjusting the antenna at all.
An antenna tuner is a kind of adjustable impedance transformer. Some tuners operate manually; you twist the knobs until the SWR meter shows a SWR, or something reasonably close to it. Other tuners are automatic and do all the adjustments for you. Taking the antenna tuner approach is not a good idea when you are using coaxial cable under high greater than SWR conditions.
The tuner may provide the 50 ohm match to your radio, but the mismatch and high SWR still exists between the antenna tuner and the antenna! This translates to high losses in the coaxial cable. At HF frequencies, the loss in ladder line is so low, you can still see good results even when the SWR is horrendous.
So which type of feed line should you use at your station? Fortunately, the answer is simple: You want the feed line that has the lowest loss at the highest frequency you want to operate.
As you probably guessed, low-loss feed lines are more expensive. A little planning and common sense goes a long way when it comes to selecting feed line. As long as the SWR is low, the loss will be acceptable. However, if you have an antenna that is feet from your radio and you are operating at, say, MHz, RG would be an extraordinarily bad choice!
When used in a multi-vertical array, verticals can even provide low-band directivity. Verticals are specifically advantageous because their superior low-angle pattern promotes better long-range DXing. The packages include industry-leading instructions and technical support.
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