Ranges of CB, LPD and PMR Communication

Описание: Ranges of CB, LPD and PMR CommunicationIn Russia there is no need to obtain a license in order to realize civil communication. Three ranges of frequencies are used. These are the CB, LPD and PMR ranges. Each of them has its own peculiarities. CB, that is Citizen Band, has the frequency of about 27 Mhz, the capacity of the transmitter not exceeding 10 Watt. Portable radio stations or transport equipment with antennae of any type, both stationary and portable compact, may serve as transmitting devices. Such communication devices are used, for instance, by some special services on the frequencies of about 27 Mhz. Even though you may freely purchase a walkie-talkie of the sort, you will have to register and to obtain a call sign to be able o use it in Russia.The next equipment type and range is called LPD - Low Power Device. The frequency is significantly higher - about 433 Mhz. However, the power is significantly lower than that of the former standard - 0,01 Watt. The power may be significantly higher, but then the walkie-talkie must be registered. This standard is used in portable transmitting devices, domestic low-power walkie-talkies with the integrated antenna and in some domestic devices requiring short-distance communication - car signaling, for instance. Another frequency standard is the PMR. Private Mobil Radio. This is a European radio system in the range of metric waves. It is used for a wide range of devices, portable walkie-talkies mostly, which in their turn are quite widespread. The frequency of the PMR is about 446 Mhz. The permitted capacity is up to half-watt. How do these systems differ practically? The CB walkie-talkies have rather long waves - about 11m, which are better at rounding obstacles and provide the longest distance communication out of the three types. They are fit for usage on the rugged ground and in forests - that is, in places where the ability to round objects is required. Such waves are scarcely absorbed by the environment. However, communication may be unstable in town due to noises. The two other standards have waves of about 70 cm long. They are fit for cities and open country, as less affected by distorts. They are also more compact, available and do not require registration.If a radio station fails to meet one of the established criteria, it is to be registered with Roscomnadzor.