In article ,
Fred McKenzie wrote:

I added a 40 Meter element to the Cobweb.

In addition to interaction with the 36" loop, I should have mentioned
that there is interaction between 40 and 15 Meter elements on 15 Meters.
The effect is to spread out the 15 Meter SWR curve in an upward
direction, increasing its bandwidth. I think that is because the 3rd
harmonic of the 40 Meter element is higher than the fundamental of the
15 Meter element.

Fred
K4DII