multiband resonant radials
 

On Fri, 03 Apr 2009 10:52:48 -0500, Bob Miller
wrote:

The Butternut radial design is simply a variation in the fan dipole
where several wires are connected at one point, but each wire
resonates in a different band.

The Butternut twinlead appears to be connected at each end, forming a
single wire folded back on itself. Is that the same as a fan dipole?

Hi Bob,

Look closely at the figure. The twin lead is connected at both ends,
true enough; but it also has added wire. The connection at the far
end of the twin lead actually defines two paths, and the connection at
the near end defines two paths. Any one path that is resonant at a
quarter wave is going to swamp the other paths' reactances.

This is the trick of the fan dipole. Those extra leads' present
hugely mismatched Zs which do not accept power, and the one lead that
is matched (at resonance) takes all the power applied - very
convenient. When you shift frequency, another wire becomes resonant,
leaving the others to mismatch. This is the simplicity of the Fan
Dipole that resides in these multi-band radials.

73's
Richard Clark, KB7QHC