The antenna is that part of your receiver which actually captures signals from distant stations. Technically, the antenna is an extension of your receiver's design even though your radio may not have come equipped with one.

Portable radios often feature a built-in antenna but most larger sets do not. If your radio doesn't have a built-in antenna, or if you would like to get better reception on your portable, then lake a moment to learn a few antenna basics.
Antennas work best when erected outdoors. Some communities place restrictions on outdoor antenna construction, so you might want to begin by checking local ordinances. The only other limiting factors will be space and the availability of structures to support the antenna.
Some basic rules for antenna construction:

	First, It is important that you get the antenna up as high as possible.
	Second, avoid sources of radio frequency noise such as power lines, transformers, heavy machinery, or fluorescent lights.
	Third, for safety, remember to NEVER cross your antenna over or under power lines.
	Fourth, remember that reception generally is best when the antenna is placed at right angles to the signal you want to receive. Of course, this means that you do not want to run your antenna parallel to power or telephone lines.

Copper wire is best for antennas. Select a good size wire that will withstand its weight and movement in the wind. Use ceramic insulators when securing the antenna wire to its support at the ends or at any points of support in between. Remember that when splicing wires together that are going to remain outside, make secure splices with bare wire against bare wire, and weatherproof the splice with a generous wrapping of electrical tape.

Connecting the antenna to the receiver is done with a lead-in wire. The lead-in for a basic long wire antenna can simply be more wire, or even a continuation of the antenna wire itself.

The lead in must not come in contact with anything that will absorb its radio energy, so use ceramic insulators to secure it along its path. Insulated wire will be handy for bringing the wire inside through a window or any convenient opening.

If you must run the lead-in wire close to radio frequency noise sources, use a coaxial cable. This type of cable transfers the signal from the antenna to the receiver through a specially protected center wire. The outside metal braid of coaxial cable shields the center wire from interference by being grounded to your receiver.

The selection of what kind of coax you use is determined by the impedance rating of your receiver. Check the manual and find out which kind is recommended to match up best. 

Check These Antenna Basics

	Run the wire as high as possible.
	Avoid radio frequency noise producing sources.
	Insulate all wire supports.
	NEVER crossover or under power lines.

The basic antenna is the long wire. However, the best reception comes from specialized dipoles. These antennas are tuned to match a specific frequency for superior performance.
A dipole is two identical lengths of wire, running at opposite directions of each other from one common starting point. It uses a coaxial cable lead-in that connects at that starting point. The center lead of the coax is connected to one wire, the outside metal braid to the other.
Remember to make secure splices with bare wire against bare wire, and weatherproof the splice with a generous wrapping of electrical tape. On the receiver end of the coax, the outside metal braid connects to the receiver ground, the inside lead to the antenna terminal. The lengths of the two wires making up the dipole are determined by the frequency you
want the dipole to maximize. The total length of the completed dipole should match the wavelength in meters on which you want the best performance.
To determine the length for your dipole, use this formula for converting frequency to wavelength: The wavelength in meters is equal to 300 divided by the frequency in megahertz. The full length of the dipole should match the length in meters of your target frequency.
If that is too long of an antenna to be practical, it will still perform well if you cut it to match one-half the wavelength. This is called a half-wave dipole. In fact, it is interesting to note that a dipole with a length cut for 30 meters will give an almost equal peak performance on 15 meters, as well as 60 meters. A multiple of the frequency is referred to as a harmonic. A division of the frequency is called a sub- harmonic. A dipole will also receive frequencies in between the peak points, but not at maximum performance.
If you live in an apartment or have limited outdoor space, you can use an indoor antenna. Often a simple long wire strung around the wall near the ceiling and hidden as much as possible will give you reasonable reception.
Another option is the vertical antenna, like the telescoping antenna of a portable. A vertical used with a broad-band amplifier is called an active antenna. These, too, work reasonably well, but pick up electrical noise much more easily.

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