If you look at Mr. Cebik's antenna pages on the web, you will see that
the circular loop is omnidirectional, and that the rectangular, diamond,
and star shaped loops create lobes along a line with the long sides
toward the corners. He has modeled a number of different loop designs,
and his pages are useful for experimenters. I don't know about
transmitting efficiency, but they are acceptable DX receive antennas
compared to other types I have tried for both shortwave and amateur.
They also require a very low level of precision in construction for
success. I think that the greatest factor is durability.
On Sun, 15 Aug 2004 12:38:19 -0400 "jerryc" <jerryc@clinchrivercorp.com>
writes:
> Tim
> Loop perimiter length and corner positions determines the lobe
> pattern. You
> don't necessarily
> have to worry about the corner angles. EZNEC will give you plot
> patterns
> and all you would
> need to do is get the locate the supports so the lobe directions
> would be
> where you want them.
> JerryC
> KC8TES
>
>
>
>
> --- Original Message -----
> From: "Tim Makins, EI8IC" <contesting@eircom.net>
> To: "Tom Rauch" <w8ji@contesting.com>
> Cc: "TowerTalk" <towertalk@contesting.com>
> Sent: Sunday, August 15, 2004 12:30 PM
> Subject: Re: [TowerTalk] Horizontal Loops
>
>
> > So, if the loop is big enough, and has the right angles, it
> becomes a
> useful
> > DX antenna ? The next question would have to be: How do you work
> out the
> > required angles ?
> >
> > I was just wondering what kind of wire antenna for DX might be
> useful if I
> > put up poles at the 4 corners of an acre of land.
> >
> > 73s Tim EI8IC
> >
> >
> > ----- Original Message -----
> > From: "Tom Rauch" <w8ji@contesting.com>
> > To: "Tim Makins, EI8IC" <contesting@eircom.net>; "TowerTalk"
> > <towertalk@contesting.com>
> > Sent: Sunday, August 15, 2004 11:12 AM
> > Subject: Re: [TowerTalk] Horizontal Loops
> >
> >
> > > > If a folded dipole performs like a normal dipole, why
> > > doesn't a horizontal
> > > > loop perform like a rhombic ?
> > >
> > > Because a Rhombic is diamond-shaped uni- or bi-directional
> > > antenna normally more than 2 WL on a leg and has the angles
> > > adjusted so the lobes from all four sides align at a low
> > > wave angle.
> > >
> > > A loop generally has no particular adjustment of angles or
> > > length.
> > >
> > > A Rhombic also has very poor efficiency along with many
> > > spurious lobes, and so is not really a very high gain
> > > antenna for the physical area. The big Rhombic at ARRL HQ
> > > for example was reported to have about the same signal as a
> > > three element monoband yagi. They do however produce useable
> > > patterns over very wide bandwidths.
> > >
> > > 73 Tom
> > >
> > >
> > > _______________________________________________
> > >
> > > 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
>
>
________________________________________________________________
The best thing to hit the Internet in years - Juno SpeedBand!
Surf the Web up to FIVE TIMES FASTER!
Only $14.95/ month - visit www.juno.com to sign up today!
_______________________________________________
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
|