Topband: Verticals and Radials

[Tom Rauch]

> ========== Over "average" ground the pattern would be slightly oval
> with a "F/B ratio" of about 1.33 dB.  Directivity favors the same
> direction that the radials run.

In an effort to bring a pattern into spec, an engineer cut and 
removed radials in the null area of the towers at WAAM radio in 
Michigan, a location with fairly good farmland.

The only measurable thing  (using normal BC FS measurements)  
that happened was the entire pattern became a little weaker, and 
the system became unstable with moisture.

An identical result occurred in the 70's at a station licensed to 
serve Bowling Green, Ohio (WMGS?) where someone did the 
same thing!

It is very possible that a 1 dB change in directivity would be 
missed, but the decrease in field strength in the desired direction 
and instability of the arrays were definitely noticeable.
73, Tom W8JI
W8JI@contesting.com