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. When constructing a fan dipole, the
general advice is to maintain some distance between the wires to
reduce interaction (the addition/subtraction of reactance to
neighboring wires). This separation is not herculean, six inches to a
foot is often quoted, and reports tend to emphasize the distant ends
being that far apart, with the ends at the common point being "fanned
out" to them (hence the term fan dipole).

Ok, looking at fig. 6 of the pdf, 4 bands,2 wires. I assume that the
long top wire is somewhat resonate on 40 and 15, with the clipped wire
being for 20 and 10. That means one wire is both 1/4 and 1/2 wave.
I should have looked better at that because I am picturing a 1/4 wave
vertical with a half wave radial...Or with rf, wouldn't that matter?


The practicality of construction is found in the separation of the
wire. The twinlead construction is going to be the most difficult
(but not impossible, obviously), whereas wire that is radically
separated will have minimal interaction (aka invisible).

So then on my triband vertical idea, I would be better off staggering
radials around in a fan shape, say one every hour of rotation, (3 bands,
4 radials) and have four resonant radials connected by some insulating
material for mechanical stability. Harder to make but easier to tune.
Going to look like a multi band vhf antenna on steroids, but as long as
it works......


I am glad I came upon this ng. I like learning about antennas, it's
about the only area left that every ham can tinker with anymore.

73,
Tim - WN8OAB
dit dit