Part In The Transmission Of Radio Waves example essay topic

Jargon buster 2 G 2 G, the second generation or GSM, is the technology currently used in the operation of mobile phones. 3 G 3 G, or third generation, is the generic term used for the next generation of mobile communications systems. The new systems will enhance the services available today and offer multimedia and internet access and the ability to view video footage. The third generation technology used in the UK is called UMTS. These services operate at 2200 MHz. (2.2 GHz).

Aerial / Antenna A device which transmits and receives radio waves. There are different designs in operation. Analogue First mobile phone technology which was phased out in the UK in 2001 with the introduction of second generation technology. Cabin A structure which protects transmitters and receivers from damage. They can be in the form of large cabins or smaller cabinets.

Cell A geographic area of coverage that a radio base stations covers. Dish Antenna Dish antenna transmit and receive highly focussed radio waves in one direction. Electromagnetic Waves / Fields Electromagnetic waves are emitted by many natural and man-made sources and play a very important part in our lives. Electromagnetic waves are used to transmit and receive signals from mobiles phones and their base stations.

The type of electromagnetic waves mobile phones use is called radio frequency (RF) waves / fields. Feeder cable The co-axial cable which connects an antenna to a base station transmitter or receiver. Frequency Frequency is the number of times per second at which an electromagnetic wave oscillates. It determines the wave's properties and usage.

Frequencies are measured in hertz (Hz). 1 Hz is one oscillation per second, 1 kHz a thousand, 1 MHz is a million and 1 GHz is a thousand million. Frequencies between 30 kHz and 300 GHz are widely used for telecommunication, including broadcast radio and television, and comprise the radio frequency band. Mobile telephone systems currently operate at 900 MHz and 1800 MHz. GSM GSM - Global System for Mobile Communications or Groupe Speciale Mobile is the international, pan-European operating standard for the current generation of digital cellular mobile communications. It enables mobile phones to be used across national boundaries.

GSM systems are operated by BT Cell net and Vodafone at 900 and 1800 MHz, and by One 2 One and Orange at 1800 MHz. ICNIRP The International Commission on Non-Ionizing Radiation Protection (ICNIRP) is an independent scientific body which has produced an international set of guidelines for public exposure to radio frequency waves. These guidelines were recommended in the Stewart Report and adopted by the Government, replacing the National Radiological Protection Board (NRPB) guidelines. The mobile network operators have accepted these guidelines and work within them.

Macrocell A macrocell provides the largest area of coverage within a mobile network. The antennas for macrocells can be mounted on ground-based masts, rooftops or other existing structures. They must be positioned at a height that is not obstructed by terrain or buildings. Macrocells provide radio coverage over varying distances depending on the frequency used, the number of calls made and the physical terrain.

Macrocell base stations have a typical power output in tens of watts. Mast A ground-based structure that supports antennas at a height where they can satisfactorily send and receive radio waves. A typical mast is 15 m high, and of steel lattice or tubular steel construction. New slimmer versions of masts are now available which can be painted to blend in with their surroundings, disguised as trees or used in conjunction with street lighting and CCTV cameras.

Masts themselves play no part in the transmission of the radio waves. Maximum Ground Level Emission Maximum Ground Level Emission or the beam of highest intensity usually occurs between 50 m and 200 m from an antenna. The ground level emission within this area is the highest circling a base station. It is usually many thousands of times lower than international public exposure guidelines. Emission levels reduce rapidly as the distance increases from the antenna. The highest emissions levels are directly in front of the antenna, 15 m or more off the ground.

Microcell Microcells provide additional coverage and capacity where there are high numbers of users within urban and suburban macrocells. The antennas for microcells are mounted at street level, typically on the external walls of existing structures, lamp-posts and other street furniture. Microcell antennas are smaller than macrocell antennas and when mounted on existing structures can often be disguised as building features. Microcells provide radio coverage over distances, typically between 300 m and 1000 m and have lower output powers compared to macrocells, usually a few watts.

NRPB The National Radiological Protection Board (NRPB) has two main functions: to advance knowledge about the protection of mankind from radiation hazards and to provide information and advice to persons in the UK with responsibilities relating to protection from radiation hazards. The NRPB has produced a set of national guidelines for public exposure to Radio Frequency waves. These have the same scientific foundation as the ICNIRP guidelines. Picocell A picocell provides more localised coverage than a microcell. These are normally found inside buildings where coverage is poor or where there are a high number of users such as airport terminals, train stations or shopping centres. Radio Base Station A radio base station is a macrocell, microcell or picocell site and consists of transmitters and receivers in a cabin or cabinet connected to antennas by feeder cable.

Second Generation See 2 G Sectored Antenna Antenna which transmits or receives higher signal levels in a horizontal direction. The antenna is split into several sectors (typically 3 or 6) to provide 360 degree coverage. Stub Mast A roof-mounted mast structure which supports multiple antennas at a height where it can satisfactorily send and receive radio waves. A stub mast is typically 4 m - 6 m high and of steel lattice construction. Stub masts themselves play no part in the transmission of radio waves. Third Generation See 3 G Transmitter Electronic equipment that generates radio frequency electromagnetic energy and is connected to an antenna via a feeder cable.

UMTS Universal Mobile Telecommunication System (UMTS) is part of the international vision of a global family of third generation mobile communication systems. The UK refers to this as 3 G. Wavelength Wavelength is the distance in metres between any two 'similar' points on a radio wave. This portion of the wave is referred to as one complete cycle. The lower the frequency of a wave the longer the wavelength.