Crosstalk in radio systems caused by foreground reflections

The effect of cross polarization was studied on two of three antennas tested. The interfering transwitting antenna was changed from its normal vertical polarization to horizontal polarization, and the effect on the reflections was noted. At Buckingham, the nearby reflections were reduced by 3 db, and the more distant reflections by 8 db. At New Holland, the distant reflection was reduced 10 db. These low numbers are in sharp contrast to the 30 odd db cross polartzation discrimination that can be realized in direct transmission at these frequencies. So this study calls to attention another limitation on selection of sites for radio relay repeater stations, already beset by a multitude of interlocking requirements. Reflection troubles can be minimized by carefully serutinizing foreground geographies of proposed repeater sites for possible reflecting agencies, and by so arranging the transmission paths as to minimize illumination of possible reflectors.