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linear loading vs lumped RE: [TowerTalk] SteppIR 40/30

To: "Richard Karlquist" <>,"David Jordan" <>
Subject: linear loading vs lumped RE: [TowerTalk] SteppIR 40/30
From: Jim Lux <>
Date: Wed, 05 Nov 2003 09:54:21 -0800
List-post: <>
At 07:11 AM 11/5/2003 -0800, Richard Karlquist wrote:
> Folding the element does little to reduce the performance. It looks
> hokie, but it's simple, light weight, more efficient than lumped
> inductance. The wires have to clear whats underneath but it's a
> wa3gin

No.  A properly designed lumped inductance is better than linear
loading.  That's why many 80 meter Yagi owners have upgraded to
W6ANR's aftermarket loading inductors, replacing the original linear
loading.  Linear loading is a marketing concept to make you think
you have eliminated the ohmic losses associated with loading
coils.  Instead, it *increases* the losses.

I am properly cynical of manufacturer's claims, but I'd be interested in some analysis of why linear loading would be better or worse than lumped. It's an interesting question.

With linear loading, there are currents in both the element and the loading, and perhaps they are higher, for more IR losses. There's also potentially a change in the current distribution on the element which would not only change the pattern, but would also change the IR losses. Intuitively, I would believe that one could build a lower loss coil than a linear inductor of the same inductance (because you need fewer feet of wire in the coil to get a given inductance, because you have the turns squared effect)

Given the remarkably low losses with decent lumped loading, even if the linear loading were 10 times greater, it would still probably be insigificant compared to the other losses in the entire radiating system (except for the few with those hilltop saltwater marshes..)


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