We have heard this numerous times from our Amateur Radio customers. Whether you are just starting out, or an oldtimer who has been hamming for years – and everyone in between – this is a fairly complicated and in depth subject.
What does an antenna do ?
This is what radiates your signal out to the world. This is the most critical part of any amateur radio station. If you are going to cut corners or save some of the budget, this is NOT the part to do it on.
So how do you select the correct antenna, when there are so many to choose from ?
Let’s look at the types of antennas available.
Verticals – Basic, can be single or multi band. Relatively inexpensive as well. Should be ground mounted with ground radials installed, which is what turns most people away from this type of antenna. An absolute minimum of 4 radials are required, but don’t expect huge results. Typically 32 or more should be installed, on the ground (they will settle in and disappear over time) or you bury them yourself.
Ground mounted verticals are good for DX because of their low angle of radiation.
The same vertical can also be installed on a roof or tower, but they require some form of counterpoise system. This is typically accomplished by hanging the radials from the base of the antenna. A good example would be installing the antenna on a roof, and laying the radials across the roof.
Radials always connect to the base of the antenna , and are run outward in equal divisions, much like the spokes of a wheel.
Here is a typical vertical antenna: https://radioworld.ca/but-hf6v
You can add some options or homebrew your own.
This radial kit by DX Engineering includes radial wire, fasteners, and “staples” to staple the radials to the ground. The staples will decompose naturally on their own.
DX Engineering also manufactures a base plate for mounting the vertical to a post, and then securing the radials to the plate.
Radioworld sells verticals by Butternut, Comet, Cushcraft, DX Engineering, Hustler, Hy-Gain, and MFJ.
Some are single band, two band, or multiband up to 9 bands. In general, the more bands that the antenna covers, or the smaller an antenna is, the more of a compromise the antenna is. Where most multiband antennas employ coils and/or traps to allow extra bands, antennas like this 43 foot vertical from DX Engineering use no coils or traps, but utilises a remote tuner (sold separately) at the base of the antenna. And you still need those radials.
Then, there are vertical antennas that employ a matching network on the antenna, with a few very short radials at the base of the antenna. These are much better for tower or roof mounting, as you don’t have wire radials hanging and drooping down, and looking messy. This is again a compromise antenna, but they do work reasonably well. Typically they cost 1.5 – 2 times more than a ground mounted vertical.
Here is an example of a multiband vertical with a matching network.
Vertical antennas are very popular due to their reasonable cost, multiband coverage and ease of installation. They are ideal for small lot sizes. They offer a uniform radiation pattern, but tend to be noisier than horizontally polarised antennas. Yes, you can work DX, but you’ll be blending in with everyone else when you’re calling that rare one.
And be sure to keep an open mind – this CB antenna covers 10, 11, 12 and 15 metres, and requires no radials.
Wire Antennas – The easiest and least expensive of HF antennas. You can purchase commercially made and pre-tuned single, or multiband wire antennas, or build your own. Typically wire antennas are configured as dipole or inverted V styles, but can also be slopers, inverted L’s, long wire or various other styles.
Some popular wire antennas, like the G5RV, require a matching network (tuner) to work properly. This would also apply to non-resonant antennas like longwires, inverted L’s and slopers.
Because of their low cost, low profile, low maintenance and decent performance, many hams build their own wire antennas. You can build everything yourself, or use some commercially made parts like this inexpensive centre and end insulator kit. Add your own wire, special dacron rope to tie off the insulators, and feedline (cable), and you’re all set !
Beams, or directional antennas, are a step up from the others. These antennas direct the signal in one direction, and reject signals from other directions. They are basically a dipole antenna with reflective and directive elements added on to a common boom. They can be for single bands or for multiple bands, but because of their size do not (usually) cover lower frequencies.
A single element antenna is a dipole. The signal radiates from the sides, but not the ends. Adding a director(s) and a reflector(s) alters the radiation pattern into one direction. The more “elements” (director/reflector elements) the more gain an antenna will have, in one direction. The antenna is aimed at the station you wish to contact. This is done with a rotator on the tower, accessed from a control box at the operators station.
Here is a three element beam for 10, 15 and 20 metres
In this picture, the signal is aimed to the left. The centre element, called the driven element, radiates the signal. The element on the right (the reflector), reflects the signal to the left. The leftmost element (the director) directs the signal to the left. Directors are physically shorter than the driven element, whilst the reflector is physically longer than the driven element. And there is plenty of math to calculate all those dimensions.
Beams can be quite large, and usually need to be supported by a tower. Some smaller beams can be mounted on smaller structures, like tripods or stand alone masts.
Here is an example of an extremely large antenna system
Like any antenna, the higher up it is mounted, the better it will perform.
To the left is a 5 element beam for 20 metres, on a 78 foot tower. Quite expensive, it requires some serious work to put up, but will give a really big signal.
So when customers come in saying they want an antenna for HF and what do we recommend, it really isn’t an easy answer. We have to ask many questions to find what works for you.
Come on in and let’s talk.
WAC, WAS, DXCC