How to make a radio antennaJanuary 11, 2014
Radio receivers have long been firmly established in our lives. We listen to music and news on the radio at home, at work, when driving in a car and walking in nature.
In order for the quality and volume of the reproduced sound to be at a high level, it is necessary that the receiver be connected to a special antenna. The design of this antenna is not particularly difficult and it is quite possible to make your own hands.
Materials and tools
For this we need the following set of parts:
- Coil of copper wire with a diameter of 1.5-2 mm or flexible cable of the same material. In extreme cases, you can use galvanized steel wire, but copper is more convenient for installation work.
The length of the wire is selected based on where and how the antenna will be placed, but in most cases, about 25-30 meters is enough. In those places where the level of the radio signal is high, the dimensions of the antenna will be minimal, in more remote areas the length of the antenna and the height of its suspension should be increased;
- Several small ceramic insulators with fixtures for them.We will need these parts in order to isolate the antenna wire as much as possible from a circuit to earth or nearby trees and structures. You can buy such insulators at the nearest radio market or remove them from old houses that are to be demolished;
- Several pieces of thin steel cable for attaching insulators to braces;
- Two roller blocks. It is very convenient to use these parts for tensioning an external L-shaped antenna;
- Plug for connecting the antenna to the receiver.
- Lightning protection device in the form of a two-position knife switch. According to the safety regulations, the outdoor antenna must be able to quickly disconnect from the equipment and be grounded during a thunderstorm.
Installation of radio antenna
The installation of an outdoor horizontal antenna begins with the choice of supports on which the insulators will be fixed. As a rule, one of the supports is installed on the roof of the house and is strengthened with wire stretch marks, and the other can be used with a tree of suitable height. After that, with the help of steel wires we fix insulators on the posts.
They will hang the horizontal part of the antenna.You shouldn’t stretch it too much, because at low air temperatures the wire “compresses” and can break. Roller blocks can be used to compensate for the oscillations of the supports and to ensure the desired tension of the antenna. To do this, at the second end of the wire there is a small load, which is thrown over the unit and through the insulator is firmly connected to the antenna.
In order for the antenna to work well, it is undesirable to make its receiving part of several pieces. In the extreme case, if there is no solid wire, separate parts of the wire are interconnected after careful stripping of their ends and sealing this place with tin. Equipment vertical descent antenna is usually not difficult. The only thing you should pay attention to is that the wire should not touch the roof or walls of the building. To this end, it makes sense to fasten the wire on a special trimmer rack that will not allow it to sway during the wind and touch grounded parts.
In order for lightning discharges not to damage the equipment and not to cause a fire inside the building, experts recommend providing the antenna with a so-called lightning protection.It consists of a two-position knife switch, the antenna is connected to the central terminal, and a cable with a plug and a grounded wire are connected to the side terminal. In good weather, the switch is thrown into the “antenna-receiver” position, and during a thunderstorm it switches off the equipment and closes the circuit “antenna-grounding circuit”. Even if the lightning accidentally falls into the antenna, the electrical discharge will go to the ground and cause no harm to people.
If the space for the antenna is limited, it is possible to make another design. It is a bundle of individual wires, which are located in the "whisk", and their lower ends are securely connected to the antenna cable.
For good contact between yourself and the cable, the ends of the wires can be poured with molten lead or tin. After cooling, the propaing site is isolated from moisture by bitumen or other similar material. Such an antenna is fixed on a long pole in any convenient place and, as a rule, gives a good level of input signal.
If there is no access to the street, it is possible to make a room antenna. Its design is much like the outdoor version,only in this case insulators are fixed indoors as close as possible to the ceiling, and the wire is stretched horizontally or coiled.