[TowerTalk] Modeling antenna traps

[Jim Brown]

On Sun,6/5/2016 1:20 PM, Timothy Holmes wrote:
> I would like to model them so that I can properly adjust them to see if it
> is even worth my time, and what the performance will roughly look like

To model the antenna, you will first need to measure the traps to find 
their complete equivalent circuit. A trap is fundamentally an inductor 
with series resistance in parallel with a capacitor with parallel 
resistance. Near resonance, they simplify to parallel R, L, and C, but 
above and below resonance, we need to know the R in series with L, 
because these values affect performance on bands below the resonance of 
the trap. And, of course, both Rs vary with frequency, thanks to skin 
effect.

73, Jim K9YC