A Submarine Direction Finder for Radar Intercept the AN/BPA-1(XN-1)
Abstract:
An experimental direction finder, AN/BPA-1(XN-1), has been developed for installation on submarines to serve primarily as a warning device against radar-equipped ships and planes. The direction finder employs a rotating, horn-type antenna system and covers the frequency range of 2300 to 10,600 Mc. The d-f antennas and drive unit are contained in a pressure-tight aluminum-alloy housing capped by a dielectric radome. Both radome and antenna housing are designed to withstand a submerged depth of 1000 feet. The antennas rotate at speeds up to 720 rpm and are capable of receiving either vertically or horizontally polarized signals. Bearings are presented automatically on a cathode-ray-tube indicator. Range tests of the direction finder against several shipborne radars indicate that it has an intercept range advantage of from 2-1/2 to 3 times the radar range against a surface submarine.