It's So High...

Finding The Perfect Antenna Location

By Jonathan Imberi

After assembling or buying a new antenna, the next step is finding a good place to put it. You NEVER want to put your antenna or its feed line under, or over, the top of electrical power lines, or anywhere that it may fall against or come in contact with electrical power lines! If your antenna was to ever come in contact with any power lines you could be severely electrocuted! You may even receive unwanted electrical noise just by running your antenna parallel to power lines that are close to your station. Power line noise can and, for the most part, will cover up all but the strongest signals your receiver will detect. It is also a good idea to avoid placing your antenna near metal objects, such as rain gutters, metal beams, metal siding, or even electrical wiring. These objects will shield your antenna and will reduce its receiving and transmitting capabilities. 

With dipole antennas the key to success is height. One wavelength above the ground is normally high enough, and this can range from 240 feet above ground for 80 meters to 35 feet above ground for 10 meters. Using this figure, you only need to be about seven feet above ground for a 2 meter dipole antenna, but you should always try to install the antenna higher to get it clear of buildings and trees. Because so very few people are able to get their antennas 240 feet in the air, most of them settle for 40 to 60 feet for their 80 meter dipoles. If you can only get your antenna up about 20 feet, do not get upset - even low antennas can work well! It is a general rule of thumb that the higher above ground and surrounding objects you can get your antenna, the better your coverage will be. You may even find this true if you can only get part of your antenna up high. 

Normally dipoles need to be supported at both ends. Buildings, trees, poles or anything high enough will work as a support. In many cases though, you will run into a situation where you are not able to get both ends of your dipole high in the air. There are two reasonably good alternatives when faced with this problem: you can either support your dipole in the middle, or just at one end. 

If the middle of the antenna is chosen as the support point, the two ends will droop towards the ground. This forms an inverted V shape, for which the antenna is named: The Inverted-V Dipole. This type of antenna works best when the angle between the wires is no less than 90 degrees. If you plan to use this type of antenna, you need to make sure that the ends are high enough above ground that no one can touch them because there are high voltages present when transmitting, which can cause RF burns to your skin. 

If you choose to support your antenna only by one end, you will notice that the antenna slopes. This type of antenna is known as a Sloper for this reason. Making sure the lowest point of the antenna is out of reach is just as important with this type of antenna. 

If you do not have enough room to install a dipole in either of the forms mentioned above, do not hesitate to experiment! After all, experimentation is the basis of the hobby of amateur radio! You can make the dipole to fit your property in various shapes. You can even make a horizontal V-shaped antenna. If you have questions about installing or creating your dipole, always remember you can ask another ham radio operator for help. 

With the six meter and two meter bands, dipoles work much better if they are installed vertically. With this type of installation you need only one support. The coax and antenna should form a right angle for as far as possible, so that it does not interfere with the radiation from the antenna. Dipoles are rarely used on frequencies above the two meter band because beam antennas are small and easy to built for the UHF frequencies. 

Building your antenna and choosing its location is only half the battle. The fun part begins with the question "How am I going to get this antenna up in the air?". You may be one of those lucky few that can support at least one end on a mast, a tower, a building, or a tree. Unfortunately, it is not always as easy as climbing a ladder and fastening your antenna. 

There are many methods of getting antenna support ropes onto the intended support. Many of these methods involve a simple weight attached to a rope or line. We have found that a sand-filled tennis ball attached to a rope works great for getting supports into trees, and this is what we use when we go camping in the summer. This method only works well for low antennas though, because it is fairly difficult to throw the ball higher than 40 feet into a tree. 

Using a bow and arrow, a fishing rod, a sling-shot, etc. are all other methods of launching the weight and rope. Please be careful when using these methods - especially if you are around other people, like at a camp site. 

After getting the support ropes in place, haul your antenna up and find a way to secure it. This leaves you with just one final step before your antenna installation is complete: routing the coax cable. After routing the cable to your station, cut it to the proper length and install the proper connector for your rig. Remember to ask local hams for help if you have trouble installing the connectors. And as always, be careful, use your head, and never work alone when doing an antenna installation. Safety always needs to come first in the hobby of amateur radio!