Topband: Response to W8JI's comments about using a K2AV foldedcounterpoise at VK6VZ

[Jim Brown]

On 9/24/2012 12:25 PM, Dan Edward Dba East edwards wrote:
> my suburban lot is small, and i would prefer to make the measurements on my property; the lot is 120'

N7CL suggested 5 wavelengths as being a viable distance for meaningful 
measurements -- that's half a mile.  Rudy's 160M measurements were done 
at only 700 ft, with a quarter-wave radiator and quarter-wave radials.  
That distance seems close, and there are elements of the results from 
that series that don't agree with N7CL's observations of the difference 
between comparable systems.

One major problem with measurements of this sort is that the presence of 
one radial or counterpoise system, even if it isn't hooked up, can 
contribute to inaccuracies when measuring the other one. Rudy noted that 
when he was doing an extensive series of measurements of 4, 8, 16, 32, 
and 64 radials, he added them a group at a time, measured them, then 
repeated in reverse order, rolling up those that he was disconnecting to 
avoid that problem.

Based on my studies, I'd expect to see differences between various not 
bad but non-ideal ground systems of the sort we're discussing here on 
the order of a few dB.  When you're trying to quantify such small 
differences, it doesn't take much to contribute significant errors.

73, Jim K9YC