Yes, and even more when buried. The velocity of propagation is
proportional to the square root of the dielectric constant if I remember
correctly, and soil is a good dielectric. Think about it this way,
.14/.25 is a velocity factor of .56, not much different than coax cable
dielectrics. The problem is more complicated because wire sitting on
the ground only sees an infinite half plane of material, but its close
enough for amateur work.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
> -----Original Message-----
> From: towertalk-bounces@contesting.com [mailto:towertalk-
> bounces@contesting.com] On Behalf Of Jim Bowman
> Sent: Friday, October 22, 2004 11:57
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Ground radials- the long and short of it
>
> On this subject, ON4UN states on page 9-11 of Low Band Dxing (3rd),
"for a
> wire ON the ground, the physical length for 1/4 wave resonance will be
> approximately .14 wavelength". Can the shortening effect truly be this
> great?
>
> Jim KS1J
> ----- Original Message -----
> From: "Ted KT1V" <kt1vbulk@demop.com>
> To: "Scott Fike" <kc0bus@hotmail.com>; <towertalk@contesting.com>
> Sent: Friday, October 22, 2004 11:25
> Subject: Re: [TowerTalk] Ground radials- the long and short of it
>
>
> > Scott,
> >
> > It doesn't matter - ground radials are not resonant. Just put down a
> bunch
> > of wire and it'll work
> >
> > 73
> > Ted
> > At 02:30 AM 10/22/2004, Scott Fike wrote:
> > >Pertaining to a ground-mounted vertical antenna with buried radials
a
> few
> > >inches below the surface of the grass:
> > >
> > > Do ground radials have to be electrically the same length as the
main
> > > vertical radiator element?
> >
> >
> > Ted Demopoulos
> > Demopoulos Associates, www.demop.com
> > Aligning Information Technology with Business Objectives.
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
with
> any
> questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
"Wireless
> Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041
with
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|