[TowerTalk] Interaction potential Hex and 40 m dipole

[Jim Brown]

One common interaction is between a resonant antenna and a nearby 
antenna on the second harmonic of the first. For example, 40M interferes 
with the 20M pattern.

There's an easy fix for this -- the 40M antenna should be shorted at the 
feedpoint on 20M. This is easily accomplished with a shorted stub that 
is a quarter wave at the resonance of the lower frequency antenna, 
located either at the feedpoint of the 40M antenna or some multiple of 
20M half waves along the 40M feedine. As it turns out, this is the same 
stub needed for 2nd harmonic suppression on the 40M antenna, and at the 
optimum location for harmonic suppression.

73, Jim K9YC

On Mon,5/1/2017 9:48 AM, Kelly Taylor wrote:
> Doesn’t Optibeam use stubs on their 40-10m multibanders to minimize interaction between 40 and other bands?
>