Radio amateurs and listeners of radio broadcasts regularly face two problems. This is erratic reception and interference. And with that, and with the other you can fight. True, different methods are used on different waves.
It is necessary
- Copper or aluminum wire with a cross section of 3-5 mm.
- Enameled wire with a diameter of 0.3-0.5 mm
- Cardboard or wood
Instructions
Step 1
There is one rule for radio reception on all bands. The receiving antenna should be located as high as possible above ground level. If there is no receiving antenna, it must be manufactured. For the LW, MW and HF ranges, the antenna can be a long bare copper or aluminum wire. The antenna length can be up to 40m.
Step 2
If the receiver has an antenna socket, there is no problem with the antenna connection. If there is no antenna jack, proceed as follows. From scrap materials (for example, cardboard or wood), make a box or frame in which to place the receiver. Wrap 5-10 turns of enameled wire onto the frame. Ground one end of the wire (for example, to the central heating battery), the antenna is connected to the other. The frame then provides inductive coupling to the internal antenna. Select the position of the receiver relative to the frame empirically.
Step 3
On VHF, you can also use an external antenna, which is quite suitable for a multi-element television antenna "Wave Channel". Such antennas were used as antennas for collective television reception. Sometimes they can still be found on the roofs of residential buildings. Connection to such an antenna is carried out using a coaxial cable, and the antenna itself must be directed to the radio transmitting station. In any case, the coverage area of even a powerful VHF station will not exceed 50 km.
Step 4
Interference can be dealt with in three ways. The first option is a directional antenna. The method applies to all ranges. At medium and long wavelengths, for receivers equipped with a ferrite antenna, this is achieved by rotating the loop antenna or the receiver itself in search of the best reception with the least amount of interference.
Step 5
Make a loop antenna to eliminate interference at medium, long and short wavelengths. It is a wooden rhombic or square frame with a side of 50 cm. Wrap an enameled copper wire with a diameter of 0.3-0.5 mm on the frame. The number of turns can be about 10. Such a frame is either plugged into the antenna and ground sockets on the receiver, or if there is only one antenna socket, the second loop tap is connected to the metal chassis of the receiver or grounded. By turning the bezel, you can tune in a station precisely and tune out interfering interference.
Step 6
You can also use outdoor "anti-noise" antennas. They represent a lumped capacitance to which a vertical drop (wire) is connected, leading to the antenna socket of the receiver. As such a concentrated container, you can use, for example, a metal rim of a bicycle wheel with spokes and a hub, fixed on a vertical insulated mast - for example, on a wooden pole.
Step 7
In any case, the signal-to-interference quality is determined by the signal-to-noise ratio. And the more powerful the received signal, the easier it is to tune out the noise, simply by lowering the volume. VHF directional antennas tend to look like television antennas. At the receiver itself, try to tune out the interference by narrowing the receiver bandwidth. Some receivers have a dedicated switch for this. This method is suitable for radio communication and is not very suitable for receiving artistic transmissions.
