[RTTY] RTTY Contesting

[Kok Chen]

If you are interested in raised counterpoises for vertical antennas,  
then I would highly recommend getting hold of Rudy Severns N6LF's  
articles "Experimental Determination of Ground System Performance for  
HF Verticals" in the last two issues of QEX, where he had conducted  
careful controlled field measurements (using S21 of a VNA between the  
test vertical and a receiving loop to measure the gain of the antenna  
system).

Parts 1 & 2 appeared in the Jan/Feb 2009 issue of QEX.

In the most recent installment in the March/April 2009 QEX "Part 3 -  
Comparisons Between Ground Surface and Elevated Radials," N6LF has  
pretty much validated the use of NEC for modeling raised counterpoises.

 From my own fooling around, I have found that proper modeling of  
radials on the ground (or buried in the ground) requires the use of  
NEC4.  If you want to do any comparisons between radial types (ground  
versus elevated), then you probably want to get hold of NEC4 instead  
of using NEC2.  However, if you just want to find out about raised  
resonant vs raised non-resonant radials, or 2 versus 4 of them, then  
N6LF's article gives good support for using antenna modeling to  
compare them, where you can use NEC2 in the numerous free antenna  
software. Both EZNEC and cocoaNEC have NEC4 support, but you need to  
license NEC4 from the Lawrence Livermore Labs.

N6LF has also validated ground mounted verticals that have "gull wing"  
elevated radials (where the radials start at ground level at the base  
of the vertical).

A radial system has to do with Near Field losses.  The quality of the  
ground around you will still determine the ultimate gain and takeoff  
angles of a vertical antenna.

73
Chen, W7AY