Tip 1: How to increase the antenna sensitivity

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Tip 1: How to increase the antenna sensitivity

Sensitivity antennas Is its ability to receive weak radio signals. It is measured in microvolts. From sensitivity antennas the quality of the receiver depends to a large extent. As practice shows, it is inadequate and then it should be increased.

Instructions

As is known, the receiving antenna performs the inverse transformation of the energy of the electromagnetic field of high frequency into electrical oscillations. Radio reception antennas There are two types - subscriber andprofessional. The main characteristic of antennas is resonance amplification, measured in decibels. So, for example, the flexible antenna of the radio station "Maycom SH-27" has a resonant gain of 15 dB, and a similar antennas, belonging to a portable radio station - 20 dB. The difference of 5 dB can increase the transmission range up to 30%. It is enough to connect a wire counterweight to the regular antenna of the radio station, as the radio communication distance is increased by 1.5-2 times.

Sensitivity antennas grows with the increase in its dimensions - length and thickness. However, today you can meet small compact antennas with a rather high sensitivity. In some cases, it is proposed to use a spherical antenna to increase it, since it has a large cross section for interaction with a gravitational field, since it has a large mass.

The quality of the radio signal is greatly influencedrenders the terrain. Reflecting from various obstacles, it is caught by the antenna in a very weakened form. If you have high-end radio equipment, then to ensure stable radio communication, you can use two space-separated receivers antennas and two receiving paths. In this case, one antenna will always insure the other if a weakened signal has come to it.

A weak radio signal causes a poor-quality image on television receivers. This problem can be solved by means of an antenna amplifier, which significantly increases the sensitivity antennas. To increase the sensitivity of the receiving devices of the radiotelephone, you first have to adjust the receiving path and then enter an additional UHF cascade at the input of the receiving device.

Tip 2: How to choose walkie-talkies

The radios are designed for voice transmission of oneman to another at a certain distance. In order to correctly choose a radio, you need to have an idea of the power of the device, frequency range and other parameters.

Radio stations are divided into two main types -professional and amateur. Amateur radios have the allowed capacity and they can be used without a special license. But for the use of professional radios will require a certificate. You will also need to register the device.

How to choose walkie-talkies, depending on the purposes and conditions of operation?

If you plan to use walkie-talkies in the forest,walking or fishing, amateur models will be a good option. In such simple radios, the settings can be changed manually, which is very convenient. For construction and installation work professional radio stations with a wide frequency range, as well as protected from dust and moisture, are suitable. And drivers should choose radio sets with a frequency range of 27 MHz. The range can be increased with the help of an automobile antenna. Within one city, you can use radios with a range of UHF. For normal operation in the mountains or forest, walkie-talkies with a frequency range of 30-50 MHz will do. If the operating conditions are constantly changing, it is better to use the tri-band portable devices.

Basic criteria for choosing radios

When choosing radios, you should pay attention tosuch parameters as: frequency bands, communication range, power and sensitivity. Short-wave range allows you to send voice messages over long distances. Such walkie-talkies are usually suitable for marine applications. CB range is designed for taxi drivers and car owners. LB-band radios are especially good for use in rural areas. As for radio stations with a VHF range, they are widely used in rough terrain. If you plan to use walkie-talkies in the city, it is better to choose models with a UHF band. They show themselves well in a densely built environment. The range of radio communication largely depends on the power and sensitivity of the device. The lower the sensitivity of the radio, the better it works. This must be taken into account when choosing. And the ability to overcome electromagnetic interference depends on the power of the radio. In a dense forest or in rough terrain, an increase in power significantly improves the quality of communication. The most effective are radio stations with telescopic and car antennas. They have a large range of action.