[600MRG] A dilemma....

[Kenneth G. Gordon]

On 31 Aug 2015 at 17:33, Marten T Beels wrote:

> Ken,
> 
> This may be a slightly different thing then what you're looking for, but
> based on the following idea a 5-band dipole can be built with one set of
> traps.  The idea is not operate the traps near resonance, but far from
> resonance and use the resulting capacitive or inductive reactance to 
> resonate the antenna.

Yes! That is exactly what I had in mind, but could find no means of calculating that.

> The best that I can find is an article by Yardley Beers (W0JF) from 
> August 1987 that refers to several equations in the appendices.  I can
> find the original article online, but not the appendices.
> 
> http://www.k0to.us/HAM/Dual%20Dipole/Beers%20-%20dual%20band%20dipole.pd
> f

OK. Thanks. I'll try to track those down.
 
> If you know the inductance of your traps, you could calculate the 
> reduced length of the lower frequency antenna with something like
> this:
> 
> http://www.see.ed.ac.uk/~jwp/radio/software/loading.html
> 
> or this:
> 
> http://www.m0ukd.com/calculators/loaded-quarter-wave-antenna-inductance-
> calculator/
> 
> (same formula).
> 
> Marten

Thanks, Marten. I'll give those a shot.

Ken