Towertalk
[Top] [All Lists]

Re: [TowerTalk] Ground Plane Model Problem

 To: K0SN , towertalk@contesting.com Re: [TowerTalk] Ground Plane Model Problem w3kl@w3kl.com Wed, 19 Nov 2008 08:15:32 -0800 (PST) mailto:towertalk@contesting.com>
 ```Tom.  I've modeled a 1/4 wave gp with one resonant radial (1/4 wavelength) using the dimension you provided using NEC4 and it yields an impedance (real part, at resonance) of 40 ohms. BTW, you didn't specify what diameter conductor you're using for the radials, so I assumed 1 mm wire.   How many radials are you modeling and what are their lengths (in wavelengths)?  The impedance will decrease as the number of radials increases.   If I use four radials the impedance at resonance is now 35 ohms.   Also, what kind of ground properties do you use with the model?  I used average ground.   73, Jeff Jeffrey K. Okamitsu, PhD, MBA +1-609-638-5402 --- On Tue, 11/18/08, K0SN wrote: From: K0SN Subject: [TowerTalk] Ground Plane Model Problem To: "Towertalk submit" Date: Tuesday, November 18, 2008, 10:44 PM Gentlemen: I have been modeling a ground plane vertical antenna with elevated radials. It's made of 3" aluminum tubing at a base height of about 15 feet. My problem is EZNEC is reporting the feedpoint impedance to be around 10 ohms, which disagrees with the conventional wisdom that says it should be in the vicinity of 50-75 ohms. Any suggestions? Has anyone encountered a similar problem while running EZNEC or another modeling program? Any input would be appreciated. Tom K0SN Porterfield, WI _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread [TowerTalk] Ground Plane Model Problem, K0SN Re: [TowerTalk] Ground Plane Model Problem, jimlux Re: [TowerTalk] Ground Plane Model Problem, Steve Hunt Re: [TowerTalk] Ground Plane Model Problem, w3kl <= Re: [TowerTalk] Ground Plane Model Problem, Steve Hunt