Very-Low-Frequency Intercept System
Abstract
An investigation of a new type of instantaneous broadband very-low-frequency intercept system to monitor the 5 to 20 kc radio-frequency band has been conducted, and experimental equipment has been developed to demonstrate its feasibility. The system permits continuous coverage of the frequency range, and provides for visual detection and bearing determination of signals regardless of their method of modulation or length of transmission. It utilizes the familiar principles of the dual matched-channel direction finder with a cathode-ray-tube presentation. However, instead of employing the conventional, continuously tunable narrow band circuits, this equipment uses wide-band, low-time constant amplifiers preceded by bandpass filters of various bandwidths and center frequencies. Signal separation within the band is accomplished visually by noting the difference in angle and length of trace of the signals in the cathode-raytube presentation. The operational sensitivity of the wideband intercept system is comparable to that of the narrowband very-low-frequency communication receivers now in use by the Navy. As many as five discrete signals, differing in field strength by as much as 60 db, have been detected and their individual bearings resolved at one time.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 16, 1955
- Accession Number
- AD1223407
Entities
People
- Kenneth G. Snyder
Organizations
- United States Naval Research Laboratory