A New 10 GC to 40 GC RFI Measuring Instrument

Our constantly expanding space age developments have an ever increasing need for more frequency channels for communications, telemetering, radar, etc. In order to maintain electromagnetic compatibility, new developments are being forced higher and higher in frequency. Some of the most recent developments have been in the X band (8.2 -12.4 gc) and Ku band (12.4 to 18.0 gc). These new higher frequency bands have created a need for new Radio Frequency Interference Measuring Instrumentation, the chief weapon used in the fight for electromagnetic compatibility. As our frequency spectrums have become more crowded, the glaring need for electromagnetic compatibility has become more apparent. No longer are contractors and manufacturers being allowed exceptions to radio interference specifications. All electronic devices purchased by government agencies must be electromagnetically compatible. The slow, laborious, and costly process of checking compatibility with most present RFI (Radio Frequency Interference) measuring equipment has shown the need for new equipment and methods. These new methods are contained in the new (January 1964) MIL-STD-826 Electromagnetic Interference Test Requirements and Test Methods. This specification calls for fast, simple, accurate, and semi-automatic methods of testing devices for electromagnetic compatibility. The Stoddart NM-62A, 1 to 10 gc RFI measuring instrument had pioneered the methods called out in MIL-STD-826. To increase the range of this instrument to fill the need at higher frequencies, the NMC-1040 Microwave Frequency Converter was designed. This paper describes the design of this instrument.