The ultimate guide to antenna construction

Introduction

After passing the amateur radio license exam and being assigned a call sign, the first question that most likely comes to mind is the choice of radio equipment. This is understandable. However, whether shortwave or VHF, it is more obvious and more useful to consider first the local environment and look for realistic antenna possibilities. The expensive high-end transceiver alone is of little use - everything ultimately depends on the best possible antenna.

Now, at the latest, many new questions arise:
  • What are my interests and goals?
  • How much space do I have available?
  • What do I have to consider for the construction?
  • How high will the costs be?
  • Can I carry out the construction alone...
  • ...or do I need additional helpers?

We consider 3 situations

within the scope of possibilities, although there are of course others.

Scenario A. The homeowner who has the ability to put a mast in the backyard, or install a larger antenna system on the house.

Scenario B. The owner or tenant of a floor apartment, who, with often limited antenna possibilities, still wants to achieve something.

Scenario C. The amateur radio operator who wants to participate in portable amateur radio on weekends or for fielddays, SOTA (Summits On The Air) and POTA (Parks On The Air) on vacation.

At first, you should have a rough idea of what you want to achieve. DX hunter, contester or work only occasionally as portable radio operator? Shortwave or VHF? CW, SSB, digital modes, QRO or QRP? Try to judge your possibilities as realistically as possble, but do not give up your dreams!

It should be clear to everyone that with small antennas one needs sometimes a lot of patience, in order to reach certain goals (DX). That excludes some some variants of amateur radio, because EME operation from the balcony would be an impossibility. On the other hand, however, do not let anybody steal your courage! Don't let anybody tell you that something is impossible, unless you spend a lot of money and have huge real estate. Sometimes it just takes more time and creative ideas.

In the following sections, the specific suggestions and recommendations for antenna construction are considered again and again under the aspect of the three scenarios A, B and C mentioned above.

During current economic sitation, most radio amateurs do not own their own house. Many of us live in an apartment. Therefore most readers will probably find themselves in scenarios B and C. Please always pay attention to this marking in the course of the text!

Shortwave

As a radio amateur in scenario A, depending on your budget, more or less everything antenna technology has to offer is open to you. On a large plot of land, it is possible to install fullsize wire antennas for the lower shortwave bands 160 m, as well as 80 m and 40 m. A maximum height is a bit more difficult to realize and requires, if natural guy points like trees are not available, the erection of guyed tubular masts made of steel, aluminum, wood or GRP.

Without suitable guy points for horizontal wire antennas such as dipoles or loops, it is easier to set up vertical antennas using fiberglass telescopic masts for the lowbands. With realistic installation heights of up to 20 m, there must of course still be sufficient space available for the guy wires and the radials. Elevated radials, which are suspended at a relatively low height above the ground, must be resonant, i.e. not shortened. An earth network laid in the ground, consisting of many individual radials of any length, can be adapted to the size of the site. However, as many radials as possible are required for good efficiency. By burying the radials, the actual effort of antenna construction is exceptionally not in the airspace, but on the ground.

For the upper shortwave bands from 30 m to 10 m, a free-standing, rotatable directional antenna with at least two or more elements is the first choice for most radio amateurs. On a smaller property, a lattice tower with directional antenna for the higher HF bands that also serves as a center guy point for one or more wire antennas is the classic choice. Terraced houses and single-family houses on very small plots of land often only allow an antenna mast to be attached directly to the house or a standpipe to be mounted on the roof.

With sufficient stability and steadiness of this standpipe, this construction can carry a not too large KW-Beam and arranged over it, directional antennas for the VHF range and turn by means of rotor. The simplest and most inconspicuous antenna solution is one of the numerous vertical antennas offered, mounted on a short standpipe on the roof. These antennas are available as quarter-wave radiators, as mono-band versions, or as multi-band antennas with blocking circuits and radials. Half-wave radiators have a greater mounting height, but do not require radials that interfere with roof walkability.

Scenario B does mostly exclude the optimal antenna options shown earlier. But also on site of the one or other rental or condominium, especially on the outskirts or in rural areas, there is usually still a garden available. With permission of the landlord or the permission by the owner community, inconspicuous wire antennas for the short wave and VHF antennas on the roof, permit a satisfying participation in the amateur radio. Unfortunately, always depending on the goodwill of the landlord or the owners' association. Whereby the receipt of an antenna permission from the landlord is sometimes easier than by the resolution of an owners' association. In all these cases, it is certainly advisable to voluntarily impose a restriction to e.g. 100 W transmitting power, instead of putting a KW power amplifier into operation and evoking the conflict case.

Indoor antennas for HF

In scenario B, with very little space, what works indoors with a ready-made antenna? Most electric antennas are too long and have very low efficiency when severely shortened. Multiband blocking circuit dipoles suspended under roof often end in disappointment because their length measurements between the blocking circuits are designed for free suspension. The environmental influences under the roof detune the antenna, the propagated resonances are completely elsewhere and the good standing wave ratio is gone.

Correction of the required lengths is extremely complex and difficult for a multiband antenna with blocking circuits. Unshortened monoband dipoles for the upper HF bands, possibly connected in parallel and fed via a common coaxial cable, are a good alternative. With such a combination, 100 DXCC countries and more can be reached with only 5 to 10 W transmit power in telegraphy. In FT8 it is possible with even less power. If there is even less space available, a magnetic antenna, in the room in front of the window, on the balcony or in the attic, is still the best solution.

VHF

Directional antennas for the VHF range 6 m, 4 m, 2 m, 70 cm and 23 cm, from the single very long yagi to the large group of directional antenna, are always possible in scenario A in optimal installation height. Ideally on a separate mast or on a mast tube on the roof of the house. Of course with a rotor, which can carry and turn the whole antenna system. Only a valley location would call these antenna systems into question and set limits.

In Situation B , this applies with the restriction that an antenna permit is available and access with an antenna feed line to the roof is possible. Good for those who live in a condominium or rental apartment on the top floor and can use a balcony or roof terrace. This makes the whole thing easier. A medium sized mast tube with rotor, directional antenna and an omnidirectional antenna placed above it, are then well within the realm of possibility. Furthermore, the broadband Discone antenna, both on the receiving and transmitting side, is well suited for entry-level use.

On the balcony of an apartment below, the possibilities are limited. Simple vertical half-wave radiators, 2-m/70-cm duo-band antennas of the X-series, ground planes as well as vertically mounted, handy directional antennas like the HB9CV or Log-Periodics are suitable in this situation. At best, a 4-element Yagi can be mounted vertically on the balcony railing and, depending on its location, pointed at relay stations a little further away.

For mounting a satellite mirror in the size, as usual for satellite TV, you can almost always find a place. If the free view to the satellite is given, already a short standpipe on the ground is sufficient. Contrary to popular belief, the highest possible location is of course not necessary under this condition. For those who have to put up with modest antenna conditions and a limited radio range, worldwide radio operation via QO-100 is an ideal supplement to local FM operation.

Antenna masts

For large HF Yagis and extensive stacked group antennas, only a lattice mast, at best a heavy tubular mast of larger diameter made from one length, comes into question. Clearly a case for scenario A. Lattice towers are made of galvanized steel or aluminum. Mast structures of this load-bearing capacity require a concrete foundation, structural analysis, and, in most regions, a building permit if the height exceeds 10 meters above ground. Check your local regulations!

Telescopic steel or aluminum masts are guyed, for VHF Yagis and small HF Yagis, equally suitable for users in scenario B and C situations. Fiberglass telescopic masts are predestined for portable applications and carry only light VHF antennas like HB9CVs or LogPeriodics. Furthermore, they are excellent for stationary and portable setup of horizontal and vertical wire antennas.

Antenna Rotors

Especially unrestricted for homeowners in scenario A, more rarely from a floor apartment in an apartment building (scenario B) there is the possibility to use an antenna rotor. Apart from extreme VHF specialists, a rotor is used rather seldom in portable operation (scenario C), in portable use the antenna can also be turned by hand together with the tube mast.

To rotate large HF yagis and extensive, stacked VHF yagis and group antennas, powerful, heavy antenna rotors with a high-quality upper bearing are required. The mechanics must be able to carry the weight of the antenna(s) including the standpipe as well as withstand the lateral forces of the wind load. Only single, small VHF antennas with a few elements on a short boom tube, can be rotated without a top bearing mounted on a short standpipe, using a small and inexpensive rotor.

Feeder cables

Coaxial cable

In most cases, antennas fed with coaxial cable are used in amateur radio, as well as in the commercial sector. From the variety of coaxial cables with 50 Ω impedance, the optimal cable has to be chosen depending on frequency range, attenuation value and maximum power. The attenuation is always given in dB per 100 m cable length. Thus, you can easily calculate back to the attenuation of the individual cable length. The cable attenuation and maximum power rating when correctly matched to 50 Ω can be found in numerous tables of data for common cable types.

Coaxial connectors

The PL-259 standard connectors and the associated SO-239 jacks already seem somewhat out of date, but still have widespread use, at least in the shortwave range, even with new equipment. Above 30 MHz in the VHF and UHF range, the N and BNC standards have become widely accepted. When buying an antenna, it is essential to pay attention to the respective connection standard. Coaxial cables can be laid anywhere on walls, in cable ducts and in the ground. When changing direction, always pay attention to the permissible bending radius.

Chicken wire

Two-wire cable, also known as chicken wire, can be used for symmetrical feeding of dipoles and loop antennas. Their impedance is defined by the conductor spacing and is usually between about 300 and 600 Ω. However, for tuned operation with a balanced antenna coupler, which is common in amateur radio, the intrinsic impedance of the line plays a subordinate role.

Open two-wire line is no longer available as a finished product on the market. So you have to build it yourself with antenna stranding and spacers or spreaders, which are still available in specialized shops. As an alternative, there are the half-open Wireman ribbon cables. They have the disadvantage that with wetness, hoarfrost, snow and ice, a high attenuation sets in fast. The open chicken wire has the edge in this respect. Two-wire lines and ribbon lines must run as freely as possible, at most with a greater distance to the surroundings. Likewise, major, abrupt changes in direction should be avoided. Ideally, an open two-wire line or ribbon line, while not necessarily perpendicular, should run from the feedthrough out of the house to the feedpoint, viewed largely at right angles to the dipole halves.

Wire antennas

End-fed wire antennas...

...are inconspicuous and easy to set up. Here the question arises, about the property size and the guy points. Sufficient space and at least one guy point in as high a height as possible, as well as a useful RF grounding in the proximity of the feed point presupposed, can be installed with small expenditure at material and costs, an effective multi-band antenna. An unbalanced antenna coupler can be used to match resonant wire lengths as well as long wire antennas of any length. High-impedance matching of resonant wire lengths (half- or full-wave radiators) is not as critical and is relatively independent of ground. The low impedance current feed at a quarter wavelength and odd multiples, only works with a usable RF ground at the antenna coupler ground terminal. Otherwise, you can't get the station ground RF-free and so-called vagrant RF causes multiple problems. Wire antennas, especially pronounced long wires (l > 1λ), are no problem in scenario A.

Endfed antennas...

...with a broadband UNUN transformer, are half-wave radiators in monoband design or with blocking circuits for multi-band operation. They also have the mechanical advantage that the feed is via a coaxial cable at the end of the antenna. The coaxial cable is not conspicuous on the house and a single, additional guy point is already sufficient. Grounding is usually not required. Residual RF occurring on the cable sheath can be eliminated with a sheath wave blocker.

Monoband dipoles...

...for the lower shortwave bands, especially 80 and 160 m, are somewhat more demanding in terms of space requirements and guy points. A horizontal, stretched suspension usually requires two guy points, ideally located on the site so that the coaxial cable leading to the feed point can be easily routed over the shortest distance. Inverted-vee dipoles require only one central suspension point (lattice mast, tubular mast or standpipe on the roof of the house) at a sufficient height, as well as two further guy points for the dipole ends at a height of several meters above the ground. From the floor apartment (scenario B), monoband dipoles will be possible, at best only for the higher bands.

Blocking circuit dipoles...

...allow operation on several shortwave bands and have reduced total span compared to a monoband dipole of the lowest frequency band. Due to the blocking circuits, the maximum power handling capacity and the usable bandwidths on the bands are reduced and narrowed depending on the design.

Chicken ladder dipoles

In the 1950s, the λ/2 long Zeppelin antenna was end-fed with a chicken ladder. One end of the chicken wire remained open at the top of the antenna and was thus more highly resistive than the side loaded by the antenna. The feed could not be fully symmetrical. As a result, the line had an asymmetry. The currents, which were in opposite phase but not of equal magnitude, did not completely cancel each other out. Consequently, the chicken wire itself radiated and created interference in the neighborhood. At the latest with the rapid spread of coaxial cable-fed amateur radio antennas in the 1960s, the good old chicken ladder fell into disrepute and into oblivion. It was not until the 1980s and later that the balanced two-wire line experienced its belated renaissance with the advent of numerous fully balanced antenna couplers. After the W3DZZ, amateur radio had rediscovered the universal and unproblematic multiplex operation of a symmetrically fed dipole.

With largely complete symmetry of antenna and coupler, the fields of the opposite-phase currents on the line cancel each other out. Except for a minimal residual component, only the dipole itself radiates. Due to the earth-independent operation, the reception is particularly quiet. Chicken ladder dipoles are mainly made for the deep bands 80 and 160 m in self-construction. They are mainly interesting for larger plots in scenario A. With shortened versions, e.g. for the bands from 40 m upwards, the chicken ladder dipole can also be considered for reduced space in scenario B.

Windom antennas...

...with a single wire feed in the original classical form, are not used in amateur radio for a long time. What remains is the modernized form with coaxial cable feed and 1:6 balun transformer, better known as FD4 or FD3 antennas. The wire antenna, operated as a half-wave radiator for the lowest band and in the harmonic multiples (or harmonic multiples) on the bands above, is fed at about one third of the total length. The off-center, laterally offset feed point can be an advantage for the down and routing of the feed line, depending on the situation on the property. However, the off-center feeding can cause problems with unbalances and sheath waves on the coaxial cable. To eliminate them, experimentation with different cable lengths and a cladding wave block is then called for. Windom antennas are predominantly something for scenario A, with restriction to the version FD3 it finds with 21 m span also still in scenario B a place.

Antennas for portable operation

Of course there are also OM who like to be portable QRV in addition to their home station. Who finds himself at home in the situation "Here really nothing more goes", has in the absolute scenario C nevertheless a chance, even very successfully in the DX business to mix. Fielddays, vacation trips, activities such as IOTA, SOTA and POTA, or be it only the occasionless portable radio operation in the free nature, offer with well selected locations, excellent antenna possibilities. With basically simple and inexpensive antennas, such as long wires, wire vertical antennas on fiberglass telescopic rods, and lightweight directional antennas, you're pretty far ahead. In any case, these outdoor activities open up far more diverse opportunities to live out most facets of amateur radio. The outdoor radio operator is thus quite well positioned compared to the "at home not at all radio operator".

If you have chosen a remote vacation spot with plenty of space for antennas, theoretically any antenna would be suitable. Unfortunately, weight, size and pack size set limits to what you can take with you on vacation. What can still go with you when traveling by car, has to stay at home when traveling by plane. Thus, in addition to weight, the ability to disassemble portable antennas is an important criterion.

Especially this group of radio amateurs in scenario C have the choice from an extensive range of portable antennas and versatile accessories. Starting with numerous lightweight and quick to set up vertical antennas, preferably for the bands 10 to 40m. They can be set up with an impact sleeve or on a short standpipe directly above the ground. A set of short radials, laid out directly on the ground or guyed low above the ground, serves as the ground net. It is also possible to set up the net at a higher level, for example on a balcony railing. For example, the "Buddipole" as a shortened half-wave radiator in the 40- to 10-m band is largely independent of the ground. This multi-band radiator requires a slightly elevated mounting with some distance to the ground. For this purpose, a standpipe in an impact sleeve or a light tripod is sufficient.

If there is more space and suitable guy points, wire antennas such as Hy-Endfed and lightweight blocking circuit dipoles are well suited. Folded and coiled, they even fit in carry-on luggage if necessary. With fiberglass telescopic masts and fiberglass rods, many individual vertical and horizontal wire antennas can be realized. Besides enough coaxial cable and antenna stranding, everything else, such as end and center insulators, balun transformers, box and wire clamps, is rather small stuff.

Sliding masts of aluminum or steel, pushed together to a length of just over a meter, allow for a larger payload when braced. Lightweight 2-element multiband directional antennas with elements of wire construction, such as Moxon-Beam, HexBeam, or Spiderbeam, are more something for a longer vacation, and their construction requires considerably more time.

Do-it-yourself antennas

Do you want to build your own antenna or buy a ready-made one? To build antennas yourself, you should ask yourself what you want to achieve. Just to save money, it is often not worthwhile to create a commercially available antenna in the self-construction. A home-built product of equal quality is certainly possible, but it may not be cheaper than a commercially manufactured product. The more rewarding motive for homebrewing tends to be the construction of commercially unavailable antenna shapes. The immediate environment at the place of residence can hardly be changed, consequently the antenna must be adapted to the local conditions. Even if an individual solution is more expensive, it is sometimes the only way to become QRV in seemingly hopeless cases.

Measuring equipment

A complete set of measuring equipment for do-it-yourself construction of amateur radio antennas, which also meets commercial requirements, is an expensive affair and is mostly reserved for the professionals. However, do-it-yourself and simple measurements on antennas are also possible with some amateur measuring equipment. In addition to a standing wave meter, which probably everyone owns, one is already well equipped with an SWR analyzer, an antenna current meter, an LC meter, a watt meter and a multimeter, if one knows how to use and exploit the possibilities of these instruments.

Tools and craftsmanship

Do-it-yourself construction of wire antennas does not require too much mechanical or handicraft skill and should be doable by anyone, since many components such as bellows housings, center insulators, end insulators, chicken ladder spreaders and the like are usually purchased ready-made anyway. With antenna strands, guy ropes, guy plates, rope clamps and box clamps, pegs and screw anchors, a wide range of individual parts is available for the do-it-yourself construction of wire antennas. Self-wound balun transformers and balun housings, extension coils and blocking circuits make somewhat higher demands on skills and the necessary tools. Yagi antennas for HF and VHF "are another house number", whose self-construction leads only with extended knowledge in metalworking and the tool equipment of a small metal workshop to success.

Technical books on antenna construction

Which technical books do you need? Recommended are "Rothammels Antennenbuch" [1], the "Praxisbuch Antennenbau" [2], the mainly practice-oriented books of the vth-series "funktechnik-berater", such as "Kurzwellen-Drahtantennen für Funkamateure" (as book on demand) [3], the editions of the DUBUS-series [4], as well as the English-language antenna literature of the ARRL [5] and the RSGB [6].

Legal issues and neighbors

Note: The following paragraph refers to the legal situation in Germany. Other rules and laws certainly apply in other countries. We ask you to familiarise yourself with the local regulations in good time before setting up an antenna system. Thank you very much.

In connection with the installation of an amateur radio antenna system, legal dealings with landlords and the members of an owners' association are governed by tenancy law or the German Condominium Act (WEG). Furthermore, municipal regulations of the city or municipality, such as development plans, may also have to be taken into account, which can vary considerably from state to state. In most federal states, for example, a mast height of up to 10 m does not require a permit. Beyond that, a building permit is usually required.

While the radio amateur in scenario A "approves" the antenna himself, so to speak, and possibly obtains further, necessary permits from the local authorities, the tenant or owner of a floor apartment is dependent on the goodwill of the landlord or the approval of the owners' association. A majority resolution of the owners' association is required for an antenna permit. In this respect, it is sometimes easier for a tenant if he is dealing with a private landlord and not a housing association or cooperative.

Even if you live in your own home, you can come into conflict with your neighbors if a large directional antenna partially covers the airspace above your neighbor's property when you turn it.

When erecting an amateur radio antenna, the relevant VDE regulations on lightning and fire protection must be observed. The proper execution of the work is a prerequisite for claiming benefits in the event of damage from building and household insurance, from exclusive antenna insurance policies, and from the DARC e.V. insurance benefits included with membership.

It can be assumed that the antenna construction work is mainly done privately. Nevertheless, it can not hurt to think about the issue of occupational safety and health. For larger actions, safety equipment such as climbing harnesses and helmets are recommended.

Last but not least, after completion of the antenna construction there is still the topic of EMC and self-declaration, the data of which can be done by measurements and/or by means of simulation via software.

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FAQ

What steps must be followed when setting up an antenna in amateur radio?

There are several steps to follow when building an antenna in amateur radio. First, you should select the appropriate type of antenna for your application, such as a wire antenna, a Yagi antenna, or a vertical antenna. Then you need to procure the necessary materials, such as antenna cables, masts, insulators and connectors. Further, careful installation and alignment of the antenna is important to ensure optimum performance.

What factors affect the performance of a homemade antenna?

The performance of a homemade antenna in amateur radio can be affected by several factors. These include proper sizing of the antenna according to the frequency ranges, use of appropriate low loss materials, proper alignment and placement of the antenna, consideration of obstacles in the environment, and use of an appropriate antenna tuner to match the impedance of the transceiver.

Are there any special tips for setting up antennas in amateur radio?

When building antennas in amateur radio, there are some tips that can help you. It is advisable to share best practices and experiences in the amateur radio community to benefit from their knowledge and expertise. Using antenna analyzers such as SWR meters or antenna analyzers can help you check the performance of your antenna and make adjustments if necessary. It is also important to familiarize yourself with the legal requirements and regulations governing amateur radio in your area to ensure compliance with all required rules.