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
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