[TowerTalk] Delta Loop Info and Opinions?

[David J Rodman MD]

I have had some experience detuning a tower.  In my case, I discovered 
my tower was acting as a reflector element for my apex up delta loop 
antenna which was adjacently located.  I modeled the system, including 
the tower and all adjacent structures.  By setting the length and 
azimuthal orientation, I was able to detune the tower, cancel the 
reflector activity and turn the tower into a director.  I added a relay 
to the system and now can change the pattern at will, depending on 
directivity required.  The relay grounds and ungrounds the wire from the 
tower.  The reason the tower was so interactive was because of the 
vertical polarization, which is predominent with an apex up loop.  You 
might also consider hanging the apex off a guy line.  I have done this 
too, but to be honest any structure within at least a 1/4 wavelength 
will be possibly involved in changing patterns.  As suggested in other 
posts, you should model the situation first before making any serious 
changes.  Good luck.