[TowerTalk] Tower Detuning

[Jim Brown]

  On 10/5/2010 10:10 AM, David Gilbert wrote:
> either 15m or 10m (I don't remember
> which band  .. maybe both) as he rotated the stack.  He was convinced he
> was getting interaction with the top sections of each guy even though he
> had them split with insulators per the usual recommended lengths.  We
> put three Mix-31 clamp-ons from DX Engineering on the top section of the
> guys out as far as I could reach from the tower at each level and the
> situation dramatically improved.

That worked for two very important reasons. First, the frequency of 
interest was much higher (20-30 MHz), and second, he used multiple 
clamp-ons.  It's also important to realize that at these frequencies, 
the clamp-on is still WELL below its resonance (in the 150 MHz range), 
so it is acting primarily as a lossy inductor. For even better results, 
you would want more turns to move the resonance down to the operating 
frequency, AND to increase the loss.  Obviously impractical on a tower 
or guy wire. :)

73, Jim Brown K9YC