Hi Charles,
Yes, we have suffered problems in a quad, but I guess that it can not be called
"Corona", just power issue.
I have designed a 4 elements quad for 27 MHz for a friend of mine who does "Key
Down" competitions.
He is running +40 Kw from a 3CX20.000 and the antenna system needs special care
to handle that power and trying to convert it in RF, not in flames. And it is
not a easy task. In the Handbook is not that information.
After some test and re-design, finally this quad is performing very good, in
fact, it is the champion (over yagis almost twice long).
The power issue is always happening in the quad´s corners, on driver and
directors, burned!!
Now is not burnng any more, after use Teflon corners over ceramic insulators
(yes, with +40 Kw fibreglass is not isolating anymore).
Coax cable is Heliax 1 5/8, but needs special care as well. since it is not
rated to that power.
You can see the setup in You Tube: http://youtu.be/R8T_KingCSs
73, Máximo - EA1DDO
> From: k4vud@hotmail.com
> To: apolloeme@live.com; adrianjamesflynn@gmail.com
> Date: Fri, 13 Jul 2012 04:55:44 +0000
> CC: amps@contesting.com
> Subject: [Amps] corona on a quad
>
>
> My understanding is that corona discharge would be most off a single isolated
> point, like the tip of a vertical ant or the ends of a yagi elements.
>
>
>
> I doubt the corners of a quad would act like that as much if at all. Likely
> someone has some hard test data on this.
>
>
>
> I also wonder if a corona charge is enlarged by the spread out and larger
> "area" of a quad loop. That is, is there a maximum charge that can be
> induced on any one isolated object or is the charge larger solely because the
> structure is larger?
>
> Inquiring minds want to know.
>
> Charles Harpole
> k4vud@hotmail.com
>
>
> ----------------------------------------
> > From: apolloeme@live.com
> > To: adrianjamesflynn@gmail.com
> > Date: Thu, 12 Jul 2012 21:11:10 -0700
> > CC: amps@contesting.com
> > Subject: Re: [Amps] Antennae (?)
> >
> >
> > Here is the story:
> > http://lists.contesting.com/_towertalk/2002-11/msg00393.html
> >
> > Best Regards,
> > Pat Barthelow AA6EG
> > From: adrianjamesflynn@gmail.com
> > Date: Fri, 13 Jul 2012 00:01:14 -0400
> > Subject: Re: [Amps] Antennae (?)
> > To: apolloeme@live.com
> > CC: alex.k2bb@gmail.com; k8ri@rogerhalstead.com; amps@contesting.com
> >
> > I seem to remember that there was 4 times as much Corona Discharge on a
> > Cubical Quad Antenna due to the 4 right angle turns.Adrian KF7DYU
> >
> >
> >
> > On Thu, Jul 12, 2012 at 11:37 PM, Patrick Barthelow <apolloeme@live.com>
> > wrote:
> >
> >
> >
> >
> > I remember Corona Discharge, aggravated by thin air of High altitude, and
> > QRO at HCJB in Quito Ecuador, literally burned, melted the antenna element
> > tips, and led to the adoption of the Cubical Quad Antenna.
> >
> >
> >
> > Best Regards,
> >
> > Pat Barthelow, AA6EG
> >
> > > From: alex.k2bb@gmail.com
> >
> > > Date: Thu, 12 Jul 2012 23:28:58 -0400
> >
> > > To: k8ri@rogerhalstead.com
> >
> > > CC: amps@contesting.com
> >
> > > Subject: Re: [Amps] Antennae (?)
> >
> > >
> >
> > > Speaking of corona discharge...
> >
> > > I remember reading an article (back in radio technical university)
> > > regarding antennas detuning due to corona at the end of elements.
> >
> > > Soviet Union, military, kilowatts :)
> >
> > >
> >
> > > ... iPhone
> >
> > >
> >
> > > On Jul 12, 2012, at 19:23, "Roger (K8RI)" <k8ri@rogerhalstead.com> wrote:
> >
> > >
> >
> > > > On 7/12/2012 8:00 PM, Jerry Kaidor wrote:
> >
> > > >>> The most effective ball on the top of the vertical is the copper float
> >
> > > >>> from
> >
> > > >>> a toilet. Especially appropriate when using 8 sweep tubes in parallel.
> >
> > > >>
> >
> > > >> *** Or six 3-500Zs?
> >
> > > >
> >
> > > > Sounds kinda fragile. I'd go for the 3CW20,000A7 myself.
> >
> > > > And there is a real reason for the ball on top. The prevent, or minimize
> >
> > > > corona discharge at those higher powers, even the legal limit on a
> >
> > > > mobile whip.
> >
> > > >
> >
> > > > Running the legal limit on multi band, stub tuned verticals can get
> >
> > > > colorful. I burned the plastic caps off the ends on one. All they
> >
> > > > needed was a 1/2" or 3/4" aluminum ball in place of the cap.
> >
> > > >
> >
> > > > BTW what material would make a good core for the matching transformer to
> >
> > > > run from 160 through six?
> >
> > > >
> >
> > > > 73
> >
> > > >
> >
> > > > Roger (K8RI)
> >
> > > >
> >
> > > >
> >
> > > >>
> >
> > > >> - Jerry Kaidor
> >
> > > >>
> >
> > > >>
> >
> > > >>>
> >
> > > >>> 73, Colin K7FM
> >
> > > >>>
> >
> > > >>> _______________________________________________
> >
> > > >>> Amps mailing list
> >
> > > >>> Amps@contesting.com
> >
> > > >>> http://lists.contesting.com/mailman/listinfo/amps
> >
> > > >>>
> >
> > > >>
> >
> > > >>
> >
> > > >> _______________________________________________
> >
> > > >> Amps mailing list
> >
> > > >> Amps@contesting.com
> >
> > > >> http://lists.contesting.com/mailman/listinfo/amps
> >
> > > >>
> >
> > > >>
> >
> > > >
> >
> > > >
> >
> > > >
> >
> > > > _______________________________________________
> >
> > > > Amps mailing list
> >
> > > > Amps@contesting.com
> >
> > > > http://lists.contesting.com/mailman/listinfo/amps
> >
> > > _______________________________________________
> >
> > > Amps mailing list
> >
> > > Amps@contesting.com
> >
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> >
> >
> >
> > _______________________________________________
> >
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> >
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> >
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