Homemade antennas are typically suited to radio amateurs as regards employees of enterprises, then get ready to buy accessories. Under ordinary citizens communicate reserved ranges 27, 433 and 446 MHz. They have been noted advantages and disadvantages, but it is considered to be the only global standard. This CB (CitizenBand) at a frequency of 27 MHz. There are difficulties with antennas Sirio and the like. It is generally accepted means of communication over long distances. Consider what kind of antenna for a radio buy.
Digital antennas for radios
More surprising that people are trying to buy a digital antenna. But the antenna - it is a passive device, not a digital or analog. Simply receiving a signal from said corresponding direction and polarization. In ratsiyah vertical polarization accepted, although there a stray and the horizontal component as well as the manufacturer is trying to place a half-wave dipole in a small case.
The antenna for the radio
How is the choice. To buy an antenna for the remote control for the TV, radio, know two things:
- Operating frequency.
Wave resistance is important, but not as these parameters. Now readers know how to buy a radio antenna to the radio, move smoothly to the consideration of the subject header.
Features range, designed for two-way radios
Workers are forced to go to different measures to reach at the desired removal. Small walkie-talkies do not pull a long distance. UHF waves can not go around the earth barriers. The front does not pass through the walls, a simple tree trunk would be an insurmountable obstacle. As a result of the industrial buildings have not heard interlocutors who are in relatively close proximity.
As a consequence, it is necessary for people to communicate by mobile, spending money. This is inconvenient, because the range is necessary to buy in order to GRKCH can check and give the green light to use. Already concluded shortcomings UHF band (300 MHz), adding that it communicate industrialists. The communication range is small, if the terrain is rough, the matter is complicated. Transmitter power is limited by law, and to get a boost of energy in the ear - not what people dream.
Modern home radio
With regard to 27 MHz, the length of this connection truckers wave. Distances are found huge, Wikipedia contains information that due to multiple reflections from the atmosphere and the earth will pass the signal will return to the point of transfer. As for other things, this kind of experimentation, there are various links. For example, in relation to the United States from Russia.
The difficulty is that the half-wave dipole length of more than 5 meters. By the way, like an antenna for CB available in the store, but a transport set, it remains unclear. We believe that the accessory is useful for the ATV on condition that he would not cling to the trees. Half-wave vibrator has a maximum gain of the available funds. Other, usually expressed in dB on different levels, so the gain in the item cards is given as a negative value. If the value is a positive sign, indicating gain relative to an isotropic radiator.
Selection of antennas for radio
The ability to use third-party antennas
It is often difficult to understand how, due to which increases the antenna. In the negative direction with increasing performance deteriorates. This, incidentally, the first thing you need to focus the attention. The second feature of antennas for radios - non-directional. This ensures that the reception from the different parties. If this need is not available, the radio arranged so that the face is constantly in a particular direction, then use safely directed television antennas. They should be rotated 90 degrees to the polarization is vertical.
In this case, the reception improves. At high frequencies, a decimeter biquadratic suitable antenna, along with the other. Difficulty in agreeing. Antenna for the radio on the car have a block, through changing characteristics. For example, a Mureny Deluxe rotary screw varies the brightness luminescence bulbs, to a maximum value. There are also other means. When carrying out commissioning will need SWR meter. With it the coefficient is adjusted to 1 - 1.5. This is considered a normal value.
Therefore, when choosing an antenna for the radio, evaluate the possibility of setting. Without this part of the power is lost. Experienced radio amateur knows that propagation conditions are not ideal in the line for the desired setting. TV antenna is designed for use with a cable impedance of 75 ohms and operate at radio 50. That means VSWR is less than 2, if you use a cable RK - 50. connection option is not directly suitable. Will occur in exactly the old situation.
When using the antenna for the radio possible use case of an active antenna, but solely at the reception (transmission to treat other techniques). In such a case, and a bad SWR can not hurt to take long distance transmission. Recall, we are talking about a time when the radio does not move, and permanently installed. Similarly create a base station, for example, the paintball when detachment commander sends Actions command. Players do not hear each other, but the base station with a powerful antenna and can transmit and receive messages.
A suitable antenna for the radio
In addition to patents, filling the internet, find other materials difficult. We believe that any antenna is equipped with the same characteristics on the reception and transmission. If you put an existing parallel amplifier, the signal will pass in the forward direction and in reverse. Note the chance to go beyond the permitted state. Transmitter power at frequencies strictly metered. Details described in Wikipedia. But perhaps there are exceptions, use its own work to increase the communication range.
Alternatively, an antenna placed higher, and the design should be active. With increasing length of the line signal begins to attenuate. If you want to throw the antenna higher for the organization of the base station, it is necessary to think about strengthening and calculate signal strength correctly. As a result, it will be possible communication over long distances at frequencies traditionally used for such purposes.
an antenna for radio frequency and connectors
When choosing an antenna do not forget about the range. For nominal operating frequency must comply. We believe that the antennas 433 and 446 MHz replace each other in the case of other can not be found. When buying look at the interface. The connector can be different from the required.
Cable with connector PL 259
For example, PL 259 buy separately and put on the cable. For this:
- Stripping 5 cm and external insulation sheath, are cut.
- Strip the central conductor 4 - 4.5 cm.
- If the main branch of the plurality of fine wires (to increase the minimum radius and bending resistance), the need for copper to tin protrusion length.
- It begins the process of joining. Like most of demountable connectors, PL 259 consists of two parts. Remove okoltsovku, tinned wire is threaded into the hole to stretch the abutment.
- As a result, it is necessary to solder the tip of the center conductor.
So use either connector (interface), and can be found in the store, for example, there http://krikam.net/shop/acc/index.php? ELEMENT_ID = 3538 for 110 rubles. According to the instructions the assembly is mounted on the RG 58 cable. C 50 Ohm - basic characteristics:
- shortening coefficient of 1.51;
- an outer shell diameter 4.95 mm;
- dielectric - polyethylene, diameter 2.95 mm;
- 50 MHz - 1.1 dB / m;
- 1000MHz - 7 dB / m.
The exact specifications refer to the network, and the material from Wikipedia, see here: http://en.wikipedia.org/wiki/RG-58.
Antenna installation type for the radio
If walkie-talkies is clear that there is a minimum of two types of installation for the mobile equipment on a magnet and locks. The first encouraging fact that the set quickly, the second stronger hold. Before buying an antenna for the radio see the future path of the cable. Sometimes a branch just passed through the door seal.