An ariel comparator and monitor unit

The paper describes a system for improved aerial selection and signal monitoring at receiving centers. The system enables any available ariel to be applied, via a coaxial switch, to a monitoring receiver whose output at intermediate frequency is displayed on the screen of a cathode ray tube; thus providing monitoring facilities at any frequency on any aerial. It also provides facilities for any two aerials to be switched alternately on to the monitoring receiver, either manually or at high speed by electronic means, in order that a visual comparison may be obtained between the two aerials on a cathode ray tube whose time base is locked to the aerial switching speed.