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Flat Coil Vs Rounded Coil

D

distortion

Active Member
Jan 1, 2006
106
1
26
atlanta, ga
What are the pro's/con's/differences between the two if any?

I would think that a flat coil would have the best performance due to sheer surface area. But I sure love my predator 10k, and it seems to work extremely well.. So I'm wondering if there is much of a difference at all.

Thanks,
Josh
 

i think it's just a gimmick.

flat bar stock was easier to acquire and bend.
 
Want more surface area? Better use a round conductor. After that, what's the biggest difference between a 'flat' coil and a 'round' one? Nothing, absolutely nothing. Except 'looks'. Like the 'round' coil? The use it. Like the 'flat' one, then use it too. All the 'hoopla' about flatter signals, more horizontal polarization, etc, amounts to the same stuff best spread on a garden to make it gow better. The sharp corners on flat coil windings tends to promote sparks, sort of. Sparks disipate energy where it doesn't really do any good (sparks = bad). But they make very good sales gimmics. You needed to hear that like you needed a hole in the head, right?
- 'Doc
 
flat coils do have an advantage IF spaced properly
Click to expand...

Please explain? This can't have anything to do with skin effect...the coil inserted into the antenna causes a field that changes the way current flows. I don't see how flat surface would change that behavior any. But I don't profess to know everything either?

Most of the antennas with flat coils that I have seen have the coils spaced too close together. At the right power levels, that sharp edge of the coil next the other sharp edge of the coild can cause you some serious problems (can you say spark plug? :) :) )
 
W5LZ said:
Want more surface area? Better use a round conductor. - 'Doc
Click to expand...

A circle encloses the maximum area, with the minimum outside dimension and a sphere encloses the maximum volume, with the minimum of outside area. So, for skin effect, flat is better.

Rich

Edited for spelling
 
less skinn effect losses with flat bar and what about turn to turn capacitance and circulating currents, i suppose the type of inductor best suited depends on where it is in the antenna and what materials are in close proximity to the windings, im sure freecell will set me straight ;)
 
I could be very wrong on this, but I don't see how the flat surface in the coil section has greater skin effect. In fact, I don't see how the skin effect is even relevent in that part of the circuit. The coil serves a very specific purpose, and it seems to me that the purpose is served with either flat or round material.
 
Assuming the longest dimention of a cross section is the same in both a circle (diameter) and a rectangle (diagonal, corner to corner), which would have the most surface area (cast the 'greater' shadow')? ('Shadow' equates to 'usable' surface area.)
Then, since most antennas using a loading coil are for a mobile, which of the two shapes would have less wind resistance? Even with today's gas prices, gas milage doesn't have much to do with it, but the resulting forces because of the shape do have considerable affect on what is required to make the antenna practical.
Then, since we're talking about things that have very little electrical affect, lets silver or gold plate the coil to increase conductivity! Which brings up a safety issue, reflected light. Ever get 'blinded' by a chrome bumper? Ever wanna beat the @#$ fool with the chrome bumper? And because of the additional movement of most antenna loading coils, flash, flash, flash sort of thingy, ever seen rhythm induced epilepsy? ...
... sort of a stretch there? Lord! I hope so, but just about as pertinant as flat/round coil windings.
- 'Doc
 
well, I guess I'd extend the idea to something simpler...a 102" whip.

If you made the whip out of flat bar stock, what difference would that make? More broad banded? I don't think it would make a difference really.
 
If you want greater conductivity than copper, the only choice for plating is silver. Gold is a worse conductor than c o p p e r (and platinum is even worse).

You could try supercooling it, but that might be impractical for a mobile installation... ;)
 
Yeah but... once you get passed the first dissimular metal connection, what'sa micro-ohm here and a miro-ohm there?
- 'Doc

And I'll quit, this is getting rediculous. Even for me.
 
what i have seen is one day a flat coil antenna will talk better than a round coil antenna one day then the next day the round coil will talk better than a flat coil.

just like a beam setup
one day you can talk flat side then next day nothing but vertical
 
KC2OST,
Sure it does, but not because of the shape of the coil windings or the polaziation of the beam. It's just normal propagation. But you knew that anyway, right?
- 'Doc
 

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