System and method for improving the interference resistance of an radio frequency antenna system through passive prescreening of the RF energy incident upon the antenna. The string includes a split bridge AC to DC converter which provides pulsating DC current to the shunted, series-connected incandescent bulbs. The light bar can include a plurality of signaling devices supported on and distributed along a base member and enclosed by a cover. Also provided are methods of using D-pinitol to promote a healthy nervous system and as a food supplement. The first polymeric material is visco-elastic when solidified. In a separate aspect of the invention, a perimeter rail, and more preferably, a discontinuous perimeter rail may be used at the edge of the base.