The Musa connector (for Multiple Unit Steerable Array/Antenna) is a type of coaxial ("coax") connector, originally developed for the manual switching of radio signals. It has a

characteristic impedance The characteristic impedance or surge impedance (usually written Z0) of a uniform transmission line is the ratio of the amplitudes of voltage and current of a wave travelling in one direction along the line in the absence of reflections in th ...

of 75 Ω, and was adopted for use in the emerging television broadcast industry.

History

"Multiple Unit Steerable Antenna" refers to an array of rhombic antennas used for high frequency (3–30 MHz) trans-Atlantic communication, "steerable" by the act of connecting several antennas together via a phasing circuit, thus achieving maximum antenna gain in the required direction. The Musa connector was developed by the British Post Office, as a reliable and readily deployed means of achieving the desired configuration. Some time after commercial television appeared around 1936, the Musa connector came to be used as a standard video connector; its distinctive feature being that unlike most other types of coaxial connector, it is engaged and disengaged by a straight push-pull action, making it ideal for patch bays. In such professional

telecommunications Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...

and

video Video is an Electronics, electronic medium for the recording, copying, playback, broadcasting, and display of moving picture, moving image, visual Media (communication), media. Video was first developed for mechanical television systems, whi ...

applications, the connector performed well until the end of analogue (525 or 625 line) television. The Musa connector was designed as to be rugged and reliable, typically using solid

sterling silver Sterling silver is an alloy composed mass fraction (chemistry), by weight of 92.5% silver and 7.5% other metals, usually copper. The sterling silver silver standards, standard has a minimum millesimal fineness of 925. ''Fineness, Fine silver'' ...

contacts, and turned silver-plated brass or

phosphor bronze A phosphor is a substance that exhibits the optical phenomenon, phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescence, fluorescent or phosphorescence, phosphorescent sub ...

bodies. In consumer products, much less expensive connectors, such as the Belling Lee coax connector, have performed the same function.

Modern use

Use of 75 Ω impedance as the standard for video broadcast equipment may be largely due to the better wideband performance obtainable from 75 Ω than 50 Ω cable of similar physical size, and is generally less expensive. The historical choice of 75 Ω has turned out to be advantageous with the latest technology. Often, 75 Ω

BNC connector The BNC connector is a miniature quick-connect/disconnect RF connector, radio-frequency connector for coaxial cable. It was introduced on military radio equipment in the 1940s, and has since become widely used in radio systems and as a common t ...

s are used, however these are not freely pluggable like MUSA connectors, due to the bayonet locking action, except for specially engineered patch panels which omit the bayonet function, just relying upon the friction of the connector's mating surfaces.

References

{{RF Connectors Navbox RF connectors