Editing Professional mobile radio (section)

==Introduction==
When private- or professional-mobile-radio (PMR) first started the systems simply consisted of a single base station with a number of mobiles that could communicate with this single base station. These systems are still in widespread use today with taxi firms and many others using them for communication. Now facilities such as [[DTMF]] and [[CTCSS]] provide additional calling selection. Because the [[antenna (radio)|antenna]] may be mounted on a high tower, coverage may extend up to distances of fifty kilometres. This is helpful especially when there is no signal in a GSM mobile phone.

Licenses are allocated for operation on a particular channel or channels. The user can then have use of these channels to contact the mobile stations in their fleet. The base station may be run by the user themselves or it may be run by an operating company who will hire out channels to individual users. In this way a single base station with a number of different channels can be run by one operator for a number of different users and this makes efficient use of the base station equipment. The base station site can also be located at a position that will give optimum radio coverage, and private lines can be provided to connect the users control office to the transmitter site. As there is no incremental cost for the transmissions that are made, individual calls are not charged, but instead there is a rental for overall use of the system. For those users with their own licences they naturally have to pay for the licence and the cost of purchase and maintenance of that equipment.

The term PMR is often used by the public and magazine publishing to refer to the low power (500 milliwatt) [[PMR446]] license exempt radio systems that consist of sixteen FM frequencies between 446.00625 and 446.19375&nbsp;MHz for analog FM and thirty-two FDMA (digital) channels between 446.003125 and 446.196875&nbsp;MHz. These are used for personal or business communications where they are legal. Split frequency repeaters are not allowed on these frequencies and these radios do not communicate with licensed PMR systems. PMR446 radios are much cheaper than those used for the licensed PMR systems.