[TowerTalk] Re: short radials, spacing

[Jan.E.Holm@telia.se]

     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.
--------------------------------
 
-----Ursprungligt meddelande-----
Från:	i4jmy@iol.it [SMTP:i4jmy@iol.it]
Skickat:	 den 6 november 2000 12:49
Till:	towertalk@contesting.com
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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