[Antennas] ground mounted vertical radials question

[Dr. William J. Schmidt, II]

<<Using more than 16 radials does not help much.>>

Prove this....  Show me mathematically how this makes any sense.

Sincerely,

Dr. William J. Schmidt, II  K9HZ
Trustee of the North American QRO - Central Division Club - K9ZC

Email: bill at wjschmidt.com
WebPage: www.wjschmidt.com

"If you drink... don't drive.  Don't even putt"  - Dean Martin.


----- Original Message ----- 
From: "Charles Greene" <crgreene at cox.net>
To: "David Ashworth" <fathom at dslextreme.com>; <antennas at mailman.qth.net>
Sent: Tuesday, November 14, 2006 8:34 PM
Subject: Re: [Antennas] ground mounted vertical radials question


> David,
>
> The best approach is to go for more radials on the order of 0.1 wavelength 
> rather than less radials that are longer.   I have a Hustler 6BTV and I 
> put 2 radials for each band about a 1/4 wave length each; however, that 
> was several years ago and I'm smarter now.  So if a radial is 0.1 
> wavelength on 80, it is 0.2 wavelength on 40, 0.4 wavelength on 20 and so 
> on so it is an effective length on all bands.  The reason for this is that 
> current in the ground radial drops off over 0.1 wavelength so making the 
> wire longer  is not necessary, but the longer wire does not degrade the 
> effect of the radial, so the longer wires are still an effective length. 
> You would think 1/2 wavelength would not be a good length as it would ofer 
> a high impedance at the antenna, but looking at the current that is not 
> the case.  Using more than 16 radials does not help much.  In other words, 
> 32 radials marginally better than 16, but not twice as good.
>
>
> 73,  Chas W1CG
>
> At 12:37 AM 11/11/2006, David Ashworth wrote:
>>Hello to all.  Will be installing a Hustler 5BTV vertical on the ground, 
>>up
>>in the country where there is no problem with people tripping over 
>>radials.
>>The radials will NOT be buried.  They will be placed upon the ground. 
>>Been
>>reading my reference material on radials, but would like to hear from
>>operators that have been there/done that.  The lowest band will be 80 
>>meters
>>and the highest 10 meters.   Hustler recommends at least two radials per
>>band.  Then, been reading W2FMI's book about short verticals.  Think he 
>>was
>>happy with about 40 radials.  Am I on the right track, the more radials, 
>>the
>>better, up to a certain point?  The soil there is very dry unless it has
>>been raining.  As soon as the sun comes out, there goes the moisture 
>>content
>>of the soil.  So, would it be better to spread, say 40 radials at 1/8
>>wavelength, or maybe 20 at 1/4 wavelength?  Would you spread some for just
>>80, or do a combination of the different bands?  If this was salt water, 
>>bet
>>you could throw a coat hanger in there, but it is not.  Any good ideas?  I
>>am leaning towards less radials and longer radials, but experience is the
>>best teacher.  Thank you for your comments/recommendations, Dave, NC6P.
>>
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