[BC] Directional Antenna Proofs - Ground systems.

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Not exactly.

For Medium Wave, a few feet won't work.

The elevated radials need to be at least 0.1 Lamda above the ground.   
This can be very significant at the low end of the band.

Experiments to seem to indicate that elevated grounds work very well,  
with far fewer radials.  However, you really need to protect the ends  
of the radials.  They are at the zero Current point, so the Voltage is  
very high.  Someone coming in contact with the end of an elevated  
radial will be very unhappy.

So, it would seem to make sense to turn them down and attach them to a  
ground rod to be "safe."  However, this appears to make them not  
work.  So, the ends need to just be left in the air.

You need nearly 120 burried elements to be efficient, and about eight  
elevated radials (even though the FCC won't accept it).  Still, hams  
wanting to save a LOT of money on a 160 or 80 meter vertical should  
elevate them.

Barry can likely amplify this.

--chip

From: "Richard Fry" <rfry at adams.net>
>Horizontal radials work differently when elevated at least a several feet above the earth than when they are buried.
>
>The experiments of George Brown et al detailed in their 1937 I.R.E. paper on buried ground systems shows that it takes 113 or more 0.412-wave  
>buried radials to produce the system performance of the same monopole on the same frequency when using only a few, elevated, 1/4-wave radials.