[TowerTalk] Re: short radials, spacing
Jan.E.Holm@telia.se
Jan.E.Holm@telia.se
Tue, 7 Nov 2000 07:37:17 +0100
I have lernt from books and antenna gurus that whats
interesting is the distanse betwen the ends of each
radial, if it´s close enough the antenna will "see" the
wires as a homogen shield. Think the magic number
was 0.05 wl but I´m not dead sure.
Bottom line is, don´t worry about the number of radials
but instead worry about the distance betwen the ends of
each radial.
73, Jim SM2EKM
PS: This is ofcourse also what Mauri is saying below in a
different way.
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Från: i4jmy@iol.it [SMTP:i4jmy@iol.it]
Skickat: den 6 november 2000 12:49
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Ämne: Re: [TowerTalk] short radials, spacing
The only reason why radial have to be more when longer, is that the
distance between them, at a considerable distance from the base,
becomes progressively bigger althought spacing in degrees would be the
same.
In term of current density and typical quarter wave verticals, the area
close to the antenna and extending to 0.125 wl is maximally important.
There is nothing to lose (but probably to gain) keeping an higher
radials number, althought they are shorter than canonical lenghts.
73,
Mauri I4JMY
> ---------- Initial message -----------
>
> From : owner-towertalk@contesting.com
> To : towertalk <towertalk@contesting.com>
> Cc :
> Date : Mon, 06 Nov 2000 06:34:44 +0000
> Subject : [TowerTalk] short radials, spacing
>
> We all know that if the radials for a vertical are short then it
> does no good to have a lot of them. Reference The ARRL Antenna Book,
> 17th Edition, Table 3 on page 3-13, and ON4UN's Low-Band DXing, 3rd
> Editiom, Table 9-1 on page 9-10.
>
> So for 60 radials .2 wl long the radials would be spaced 6 degrees.
> Likewise, for 36 radials .15 wl long they would be spaced 10 degrees.
>
> Now consider an 80m 4-square array. Assume each vertical will have 60
> radials .2 wl long (6 degree spacing). In the interior of the array
> the radials will be much shorter than .2 wl. (Ranging .125 to
> .17 wl). Question: Can (should) there be fewer interior radials since
> they are shorter? Or should the 6 degree spacing be maintained?
>
> Kris N5KM
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