November 2012 | NTIA Technical Memo TM-13-492
Frank H. Sanders
Abstract: This Technical Memorandum describes a process for selecting an appropriate antenna for monitoring radio signals from airborne transmitters. A mathematical formula for the optimal receiver antenna gain is presented. This formula takes into account the factors of minimal required signal-to-noise ratio of signals in a monitoring receiver, airborne radio transmitted power and antenna gain, airborne radio height and resulting maximal line-of-sight coverage, free-space propagation loss, airborne radio signal bandwidth, monitoring system bandwidth, and the sensitivity of the monitoring system’s receiver. The optimal monitoring antenna gain is calculated as a function of elevation angle above the local horizon. That function is used to select an antenna type that will receive signals from as many airborne radios as possible. A worked example of the selection process is presented. Although it is assumed that a terrestrial system will be used for monitoring, the process can be applied to antennas for marine and airborne monitoring systems as well.
Keywords: antenna gain; RF measurement; airborne signals; RF monitoring
For technical information concerning this report, contact:
Frank H. Sanders
Institute for Telecommunication Sciences
Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.