Hi John,
Experiment!
However, there's no reason to logically assume that the "counterpoise" you
refer to would work -- since, again (I stated this last time), the three 25'
long radials required by the GAP Challenger are not a counterpoise at all,
they are bottom-loading the antenna to resonance. Changing their lengths
changes the resonant frequency of the antenna itself. They're 25' because
that's how much capacitance is required to resonate the antenna, and since
the Challenger has virtually nothing to tune and adjust (main radiator
element lengths are not adjustable with this antenna), you pretty much have
to hit resonance by design.
WB2WIK/6
"If everything seems under control, you're just not going fast enough." -
Mario Andretti
> -----Original Message-----
> From: John von Gonten [SMTP:n5bsd@arrl.net]
> Sent: Monday, October 07, 2002 8:54 AM
> To: Steve Katz
> Cc: TowerTalk
> Subject: RE: [Towertalk] GAO Challenger DX
>
> I plan on guying the antennae anyway I mount it, but in order to keep it
> out harms way around here I have to lift it, the only place that I could
> ground mount it and be sure it was out of the way enough would put the
> top of the antennae into or far to close to the power lines that run
> beside and behind my house. So an elevated mount, on the side of my
> shack is about the only way I can garuntee it some saftey, I am looking
> at starting it on a 10 ft pole with guys some 30 ft from the ground,
> putting them 20 ft up the antennae itself.
>
>
> As far as the counterpoise, I have a radil set the consists of 4 8'6"
> aluminum sticks, extruded, heavy aluminum. I am wondering if elevated,
> these can take the place of the 3 25' wires sold by GAP for this
> antennea.
>
> As I have said before I have limited space and currently limited funds,
> so the challenger fits both, just need to keep it from getting run into.
>
>
>
> On Mon, 2002-10-07 at 10:14, Steve Katz wrote:
> > John,
> >
> > I wouldn't recommend elevated mounting of the Challenger DX. As I've
> stated
> > before, if you had one on hand, and lifted it off the ground, you'd know
> > pretty quickly why this isn't recommended. It's top heavy, catches a
> lot of
> > wind, and really needs a strong, substantial base, or the base will be
> the
> > weak link that renders the antenna scrap aluminum in the yard below.
> >
> > However, just for clarification, the three 25' wires attached like
> radials
> > to the base of the Challenger are not a counterpoise. They are
> > bottom-loading to achieve resonance on 40/80 meters, and do nothing at
> all
> > on the higher bands. The Challenger is not a base-fed vertical, it's
> > center-fed, with linear loading on most bands as well as bottom loading
> on
> > 40, and top and bottom loading on 80. I've disconnected the wires
> > completely and noted zero impact on 20-15-10m, but a rather dramatic
> impact
> > on 40/80 (like a resonance shift, completely out of the band).
> >
> > WB2WIK/6
> >
> > "If everything seems under control, you're just not going fast enough."
> -
> > Mario Andretti
> >
> > > -----Original Message-----
> > > From: John von Gonten [SMTP:n5bsd@arrl.net]
> > > Sent: Sunday, October 06, 2002 1:59 PM
> > > To: towertalk@contesting.com
> > > Subject: [Towertalk] GAO Challenger DX
> > >
> > > I am looking at starting my station with a GAP Challenger DX Antennae.
> > > I will have to mount this at least 10ft off the ground to keep it out
> of
> > > harms way, too many accident prone people around here. :)
> > >
> > > Does anyone have suggestions on the performance and use of
> counterpoise
> > > when elevated for this antennae?? And how well do they work for DXing
> > > and contesting? I am trying to find more real world data on this, my
> > > budget and lot prevent me from getting to elaborate with my antennas
> > > currently.
> > >
> > > I have had a few people tel me they are strictly ground mount and even
> > > the GAP tech support people have no ideas on how the counterpoise
> would
> > > work in an elevated situation.
> > >
> > > Any and help will be greatly appreciated.
> > > --
> > > 73
> > >
> > >
> ------------------------------------------------------------------------
> > > | John von Gonten - N5BSD | ERROR 406: file corrupt:
>
> > > | Grid-Square: EM12lr | config.earth --- reboot universe?
>
> > > | Email : N5BSD@rblprd.com | (Y/N)
> > > | WEB : http://www.rblprd.com |
> > >
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> --
> 73
>
> ------------------------------------------------------------------------
> | John von Gonten - N5BSD | ERROR 406: file corrupt:
> | Grid-Square: EM12lr | config.earth --- reboot universe?
> | Email : N5BSD@rblprd.com | (Y/N)
> | WEB : http://www.rblprd.com |
> ------------------------------------------------------------------------
>
>
> -----BEGIN GEEK CODE BLOCK-----
> GO d- s a- C++ BL* P+ L++ E--
> W++++ N+ o++ K- w+ !O M V- !PS
> PE+ Y+ PGP++ t 5 X+ R tv++ b++
> DI+ D G e>e+ h! r++ y++>* UF++
> ------END GEEK CODE BLOCK---
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