Vertical polarization-VORTAC´S last weak link

This paper discusses a problem with the VHF Omnirange System (VOR) which prevents it from performing to its full potential. Some courses on many stations have an unnecessary amount of error plus roughness and scalloping which differs with each aircraft and in each location that it is received. The majority of these effects are not caused directly by reflecting objects as commonly believed. The cause, vertical polarization, and method of correction have been known for many years, but unfortunately have not been properly recognized or universally applied. Tests and corrections should be accomplished in order that those who wish to continue to use the VOR in what is probably its last ten to fifteen years, are provided the best available short distance navigation service without the expense of installing additional equipment in their aircraft