TV aerial plug
TV aerial plug
|Type||RF coaxial connector|
|Designer||at Belling & Lee Ltd in Enfield, United Kingdom|
|Designed||Around 1922 (Belling-Lee)|
Antenna plugs are male antenna connectors that fit into female antenna sockets.
Antenna sockets are female antenna connectors that have slots or holes which accept the pins or blades of antenna plugs inserted into them and deliver or receive TV signal to or from the plugs. Sockets are generally mounted on the TV set or in the wall. Sockets are usually designed to reject any plug which is not built to the same standard. Some sockets have one or more pins that connect to holes in the plug.
The Belling-Lee connector or IEC 61169-2 connector (formerly IEC 169-2), known colloquially in countries which use it as a TV aerial plug, a TV antenna connector or simply an antenna plug, is commonly used in Europe and Australia to connect TV sets and FM / DAB-radio receivers to terrestrial VHF/UHF roof antennas, antenna amplifiers, and CATV networks via a coaxial cable. It is one of the oldest coaxial connectors still commonly used in consumer devices.
Invented at Belling & Lee Ltd in Enfield, United Kingdom around 1922 at the time of the first BBC broadcasts, it was originally only intended for medium frequency broadcasts, where accurate impedance matching of an antenna connector is not a concern.
Belling-Lee vs other connectors
|This section needs additional citations for verification. (October 2013)|
Unlike the coaxial F connector used today for the same purpose in North America, the IEC 61169-2 connector is not matched to the 75-ohm characteristic impedance of the antenna cable used, having an impedance closer to 50 ohms. This lack of impedance matching causes signal reflections in the cable, leading to noticeable signal distortion on VHF and UHF frequencies (but not MW or Shortwave).
- The IEC 61169-2 connector is recognised as a source of signal distortion and has become a particular concern with digital signal reception, specifically UHF HDTV.
- DAB (digital radio) and other reception modes are not as severely affected by the impedance matching issue, so only HDTV and satellite reception systems are encouraged to use the F connector.
- In spite of being somewhat unsuitable for modern analogue VHF and UHF TV frequencies, due to industrial inertia, the Belling Lee connector is still used today as a TV signal reception connector.
- In Europe and the Americas this connector is not used to connect satellite TV antennas. The more electrically suitable 75-ohm F connector is standard. However, the obsolete BSB receiver used a Belling Lee connector for the LNB feed as did the MK1 Nokia SAT1700 analogue Sky receiver. (The MK2 used 'F' connectors.)
Miniature Belling Lee
There is also a miniature Belling Lee connector which was used for internal connections inside some equipment (including BBC RC5/3 Band II receiver and the STC AF101 Radio Telephone). The standard Belling Lee plug is about 33 mm long and 9.5 mm diameter (mating surface); the miniature version looks similar but is only about 17 mm long and 4.4 mm diameter. Amalgamated Wireless Australasia (AWA) used miniature Belling & Lee connectors, internally, in their 25M series Land Mobile two-way radios in the early 1970s. The socket is a Belling & Lee L1465/CS whilst the plug is a Belling & Lee 1465/PF.
- International Standard IEC 61169-2: Coaxial unmatched connector (= British Standard BS 3041-2).