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 single wave propagating along the line; that is, a wave travelling in one direction ...

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 bay A patch panel is a device or unit featuring a number of jacks, usually of the same or similar type, for the use of connecting and routing circuits for monitoring, interconnecting, and testing circuits in a convenient, flexible manner. Patch ...

s. In such professional

telecommunications Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than tha ...

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 of silver containing 92.5% by weight of silver and 7.5% by weight of other metals, usually copper. The sterling silver standard has a minimum millesimal fineness of 925. ''Fine silver'', which is 99.9% pure silver, is ...

contacts, and turned silver-plated brass or phosphor bronze 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 (initialism of "Bayonet Neill–Concelman") is a miniature quick connect/disconnect radio frequency connector used for coaxial cable. It is designed to maintain the same characteristic impedance of the cable, with 50 ohm and ...

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