[TowerTalk] abreviated radial systems

[Rudy Severns]

I have recently completed a series of tests comparing the signal strength 
between a 40m vertical with 32, 1/4-wave, radials in a complete circle to 
the same vertical with a sector missing from the radial system.  This 
represents the case of placing a vertical near an obstruction such as a 
building.  Even over my rather good soil the results are discouraging. 
There is signal reduction in all directions but the greatest reduction is 
towards the missing sector.  I observed from 0.5 to over 3 dB of signal loss 
in various directions.  Over poor soils these numbers would be even worse. 
This does not take into account the loss due to a building in immediate 
proximity to the vertical which is not likely to have a positive impact. 
NEC modeling gives similar results to my experiments, overall signal 
strength is down and the pattern is distorted.

These results will be published in the Nov/Dec 2009 issue of QEX magazine. 
In the meantime I suggest that placing a vertical against a building is 
probably a bad idea.  If you have any other option, take it.

73, Rudy N6LF