Topband: Measuring field strength

[Tom Rauch]

> 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.

I measured dozens of systems and that method will not work 
except by pure luck.

As an example just a few moths ago Roy Lewallen and I 
measured a series of 40 meter vertical radial system. We had 
a very low base impedance with four elevated radials (about 
40 ohms) but about 16 buried radials produced identical FS 
with a base impedance of about 60 ohms.

I've found the same to be true when measuring FS on 160 and 
80 meters, as well as the BC band.

I also think Rudy Severns posted something on here a month 
or two ago agreeing with this.

If you want to know  FS change you really have to measure 
the FS.

73 Tom