Topband: Measuring field strength

[Telegrapher9 at aol.com]

Dan,

five wavelengths will be far enough. An indirect measurement can be as good 
as a field strength measurement. If you can accurately measure the base 
impedance at resonance you can calculate the change in field strength. This is done 
by simulating the antenna over perfect GND. You then know the feedpoint 
resistance. In actual use the feedpoint resistance will be higher. The difference is 
due to losses. The radiation efficiency is then calculated. As the GND system 
is improved the base resistance will decrease. I use this method and it is 
convenient. It has confirmed simulations and articles that say that many short 
radials is not much better than a few short radials. 

    Dave WX7G