New pin insulators free from radio interference

Electric power transmission lines employing ordinary pin type insulators may cause radio interference although otherwise in good operating condition. With more than 13/000/000 radio receiving sets in the United States the seriousness of this problem is at once apparent. Accordingly, several manufacturers have developed insulators that are claimed to be free from interference at their rated operating voltages. In this article comparative tests on some of these insulators are described and the relative merits of the different designs are pointed out.