[SMCARA] Couterpoise Question
Rene Ramirez
w3bnyren at gmail.com
Thu Sep 25 09:54:19 EDT 2014
I once got caught up in the whole counterpoise issue. I have a zero three
antenna and I have 60 40' #14 stranded THHN lowes copper wire at dirt
level. IF you can elevate them then yes you can do the tuned radials thing
(which I might add can be a PITN...literally if you clothes line yourself)
but not actually needed. Why 60 radials? thats all the holes my DX
engineering mounting plate had. I could have doubled up to 120 radials but
I felt it wasnt necessary. Yeah I could have gone and done some modeling
etc but I wanted to get on the air. and 60 40' radials is a fair amount of
wire to measure, cut, crimp, solder, wash, rinse, repeat! Also, funny
thing about elevated radials is you really cant use that area for any kind
of recreation, dog walking etc without disturbing them. bummer...
So just get wires down, (there is a method to do this and its almost time
to start that will keep your radials and the mower from meeting...ask me
offline or separate email on how to do this) and the antenna up and get on
the air and see what it does.
Ren...
On Thu, Sep 25, 2014 at 9:40 AM, Bill Jones <merc669 at gmail.com> wrote:
> The End-Fed antenna is the Ultimax DxExtream 77 foot antenna. This I plan
> on one end in a tree about 40 feet up and slope it to 10. The balun itself
> will also have a 1:1 isolation balun for RF feedback prevention near the
> feedpoint and then going into the house. I have also read that length does
> not matter for counterpoise and others that say run a single length for the
> lowest band and have a few of these laid. All different opinions...
>
> Bill
> KC3DEZ
>
> On Thu, Sep 25, 2014 at 9:07 AM, Clarke, Tom AIR4.0P NATOPS <
> frederic.clarke at navy.mil> wrote:
>
> > Bill,
> >
> > I think the answer is "it depends"! Conventional wisdom has it that the
> > length of the radials are not as critical when on the ground or buried.
> > Ground conductivity gets into the act here also. Things would be quite
> > different in Arizona!
> >
> > In your case the 8.6 foot radial is a "tuned" radial and should be in
> the
> > same plane as the antenna, although not critical if it hangs vertically
> > (although it may affect the directionality somewhat. In the case of the
> 80
> > meter radial, again it should be elevated to function as a tuned radial,
> > but if your situation calls for it to be on the ground, the elevation of
> > the feedpoint should not be added to the radial length, as it is all part
> > of the radial length. Since part of the counterpoise is on the ground,
> it
> > will become detuned by the earth anyway. There are several treatises in
> > the ARRL archives concerning grounds, radials, and counterpoises.
> >
> > FYI, I have a ground mounted vertical antenna and I simply have 32,
> > twenty-five foot radials on the ground or slightly buried. This works
> very
> > well. When I had this antenna mounted on a tile roof in EA7 land, I
> used 4
> > elevated, stub-tuned radials which worked very well. Adding additional
> > radials on the roof did not make any noticeable difference.
> >
> > What kind of end fed antenna are you using?
> >
> > Tom/W4OKW
> >
> > -----Original Message-----
> > From: SMCARA [mailto:smcara-bounces at mailman.qth.net] On Behalf Of Bill
> > Jones
> > Sent: Thursday, September 25, 2014 6:08 AM
> > To: smcara at mailman.qth.net
> > Subject: [SMCARA] Couterpoise Question
> >
> > If I need a 65 to 70 foot counterpoise for 80 Meters and a 8.6 foot one
> for
> > 10 Meters and my balun from my end-fed antenna is 10 foot up do I need
> to
> > add 10 feet to the math to get the counterpoise to ground level for it to
> > be effective. In the example of 10 meters the wire is just hanging in
> air.
> > These would be run opposite to the feedline. Thanks!
> >
> > Bill
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