Re: NEC-LIST: Re: NEC-List Digest, Vol 3, Issue 15 Coil Loading

With apologies to the Canadian server computer about my inability to conform
to its expectations:

I do not recall NEC4 taking the (appropriately) named proximity effect into
account. The pitch of practical helix antennas seems to be such that the
proximity effect is negligible. Modeling a multiple turn loop antenna
probably could benefit from including the proximity effect. What other
structures would benefit from its inclusion in NEC4?

    Here is an example of where measured and modeled could be compared.
However, building on what Roy has observed, if the Q gets above something
like 250, I expect measurement to be problematic.

    Regards, Mac

J. Mc Laughlin; Michigan U.S.A.
Home: JCM_at_Power-Net.Net

"Mike Jacobs" <mj_at_star-h.com> writes:
> On the subject of coil Q, I have been working on a project that required
> the use of high-Q coils for efficient tuning of a short dipole and have
> looked at using NEC-4.1 for modeling air-core coils using a wire
> conductivity LD command to get a value for the loss in the coil. I recall
> reading something by or hearing from Gerry Burke that he had
> successfully used NEC to model some inductors. My models appear to
> be valid and the results seemed reasonable for some conceptual coils
> sizes and values, but I haven't tried building and testing a real-world
coil to
> check against the NEC values. Does anyone have any experience with
> this? I am aware of certain NEC limitations with small loops, but the
> inductor coil models seemed to work. With respect to my project, the
> design has morphed to one that lets me use vacuum capacitors instead of
> inductors, and here I am confident I can get a Q of 1000.
>
> Mike Jacobs
> STAR-H Corporation
>

-- 
The NEC-List mailing list
NEC-List_at_robomod.net
http://www.robomod.net/mailman/listinfo/nec-list