Hello George:
Several folks have asked for additional information. Here it is.
My co-authored article on the 160 meter inverted parasitic slopers (4 wire
elements) was published in QST, page 36, August 1994.
One system that I tried but was not satisfied with (gain and F to B was poor)
was the K1THQ 5 element (1 driven and 4 parasitic) sloper array. Dave is now
K1WA. The antenna has been in the ARRL Antenna book for many years, but my brand
new 20th edition (with GREAT software I must add) has it on page 6-38. Dave
built his antenna for 40 meters and I used NEC to scale it to 160. I had the
same poor results with a properly installed K8UR system.
My current 160 meter antenna is described in great detail in the latest ON4UN
Low Band DX book. It is a 5 element parasitic vertical yagi array ( uses one
common tower for support and the driven element with 2 active parasitic "T" wire
elements. It has 5 dB of forward gain at about 24 degrees take off and 32 dB of
front to back). It is the only system that was better than the array Jim, AL and
I designed in the 1994 QST article. The only difference in my current 160 system
from John's book , is that I have extended the radial field recently (added 1/2
wave length radials) and there is now 16 miles of #16 wire on the ground. This
system has an omni mode which is valuable for stateside contests. I'll add some
additional photos of this antenna to my web site in a few weeks.
The Lazy V array is much easier to install (assuming you have a tall tower) and
does not depend on ground radials. Many K3LR Lazy V arrays have been installed
on 160, 80 and 40 meters. The gain and front to back ration is excellent when
installed correctly. The article DOES take into account the effect of the
mandatory current choke (balun).
73!
Tim K3LR
http://www.k3lr.com
George & Marijke Guerin wrote:
> Hi Tim,
>
> Tim,
> Can you tell me in which issue the article was published?
> Thanks George K8GG
>
> ----- Original Message -----
> From: "Tim Duffy K3LR" <k3lr@k3lr.com>
> To: "Ron Feutz" <feutz@wctc.net>
> Cc: <topband@contesting.com>
> Sent: Saturday, December 06, 2003 6:44 PM
> Subject: Re: Topband: K8UR array
>
> > Hello Ron:
> >
> > You might want to take a look a my QST article about the Lazy "V" array
> that I
> > used and was published in the early 90's.
> > I installed the K8UR array and the full sloper K1THQ array prior to
> settling on
> > the design that I worked on with WA3FET and K3LC (QST article). Both UR
> and THQ
> > arrays had disappointing results at my QTH.
> >
> > Good Luck and 73!
> > Tim K3LR
> >
> > Ron Feutz wrote:
> >
> > > Topbanders,
> > >
> > > I have long wanted to put a K8UR array (1/2 wave dipole 4-square with
> > > center fed elements pulled back in at the bottom) or a similar array
> using
> > > straight dipole slopers, on a 240' SSV commercial 2-way tower that I
> > > own. The tower scales up nearly exactly from the 80 meter array in
> ON4UN's
> > > book. I have a Comtek 4-sq controller that I intend to use.
> > >
> > > ON4UN does not show baluns at the feed points; the Comtek manual does.
> Are
> > > baluns necessary? I would prefer to not use them to lighten the wind
> and
> > > weight load on the antenna/tower.
> > >
> > > The pattern shown in John's book for the K8UR array has a very broad
> front
> > > lobe and a poor front-to-back, making the array a less-than-ideal RX
> > > antenna. Is there anyone using one who could give me advice on this? I
> > > lease only a small plot where the tower sits, and don't know if I could
> get
> > > permission to put RX antennas nearby.
> > >
> > > The pattern for the array with straight sloping dipoles shows a sharper
> > > front lobe and a much better F/B, but it has lots of high angle
> radiation.
> > > It seems to be a trade off, but my gut tells me the straight dipole
> sloper
> > > array would be a better RX antenna.
> > >
> > > Is there anyone out there who could model this for me? It would be nice
> to
> > > know the right length for the dipoles at the start, as cut-and-try would
> be
> > > a very cumbersome tuning method.
> > >
> > > 73,
> > >
> > > Ron - WA9IRV
> > >
> > > _______________________________________________
> > > Topband mailing list
> > > Topband@contesting.com
> > > http://lists.contesting.com/mailman/listinfo/topband
> >
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> > Topband mailing list
> > Topband@contesting.com
> > http://lists.contesting.com/mailman/listinfo/topband
> >
> >
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