[Antennas] Loop vs Dipole

Fri, 03 Oct 2003 12:14:47 +0000

Geo
  I feed my loop at the apex, at the high current point. When I was in grad 
school, that was the point that radiated, I sugest it still is. Also some 
suggest the feed at the top results in vertical polarization, at the bottom 
center, horizontal polarization. Is it possible that insufficient height 
above ground is working against you? I hope you are using a balun with 
proper ratio. and not using open wire feeders.
   My configuration works well on all bands, It worked so well for me that I 
have 3 loops phased. My performance this week, included a 15 minute chat 
with Taiwan, a QSO with a station in Viet Nam, several S-9+ reports from 
Japanese stations on SSB, reports from Europe and Eurasia that I was the 
loudest station on the band. And all this from my 100 w old Kenwood.
   On second thought, I am on a ridge looking north, that slopes about a 
thousand feet downhill to the North. My array is fixxed at magnetic North. 
my modeling software suggests that the electrons roll downhill and pick up 
inertia. Also, there is the pine needle and oak leaf factors, as I am in the 
immediate vicinity of several.
Regards,
KZ5V   aka Gene Mason

From: "George,  W5YR" <[email protected]>
To: <[email protected]>, "Ron & Madhavi" 
<[email protected]>,<[email protected]>
Subject: Re: [Antennas] Loop vs Dipole
Date: Wed, 1 Oct 2003 20:40:38 -0500

Actually, modeling my loop shows that feeding it at the high apex of the
loop produced the worst results. I feed at the center of the bottom
horizontal section and both the model and the results confirm that this is
be best for my setup.

73/72, George
Amateur Radio W5YR -  the Yellow Rose of Texas
Fairview, TX 30 mi NE of Dallas in Collin county EM13QE
"Starting the 58th year and it just keeps getting better!"
[email protected]

----- Original Message -----
From: <[email protected]>
To: "Ron & Madhavi" <[email protected]>; <[email protected]>
Sent: Wednesday, October 01, 2003 7:42 PM
Subject: Re: [Antennas] Loop vs Dipole

 > Ron, I have to agree with George, feed it with ladder line and a balun at
the tuner, also, I am assuming your feeding the system at the top and not at
the bottom corners, should do better feeding it at the top, dont really know
the physics why that it but that has been my experience... good luck... I
love loops and Bi-Squares...73  Tim K8WBL
 > >
 > > From: "Ron & Madhavi" <[email protected]>
 > > Date: 2003/09/30 Tue PM 01:13:41 EDT
 > > To: <[email protected]>
 > > Subject: [Antennas] Loop vs Dipole
 > >
 > > Here's a tough one....or is it?!
 > >
 > > I live in a townhouse in Kingston - the backyard is no more than 32'
long
 > > and 10' wide, with a concrete parapet wall at the back.
 > >
 > > I have a 25' tall aluminum pole clamped to the wall and ran an inverted
vee
 > > on 20m (25' at the apex). Results were fair and with my 850S, I worked
into
 > > Asia and more consistently into Europe.
 > >
 > > Wanting to improve on it, I replaced the vee with a full wave loop and
 > > expected it to outperform the inverted vee. The loop has perfect
resonance
 > > (a nice 1.1 SWR). The matching is done with a  1/4 75 ohm transformer.
 > > HOWEVER, even though I have tried to move the feed to a corner, 1/4 
from
a
 > > corner, center, apex etc., nothing seems to make it outperform the
inverted
 > > vee. I know that this does not confirm theory -- as the loop is larger,
has
 > > a lower take off angle (at least so they say!) and better SWR etc.
 > > Adddmitedly, the base of the delta is a FEW feet lower off the ground
than
 > > the ends of the vee, but I expected the claimed superiority of a full
wave
 > > loop to offset that.
 > >
 > > Used many 40/80m lops in the past, but never compared them to dipoles
and
 > > vees at the same height! The results however were quite pleasing. First
time
 > > I am running comparisons on  loops and dipoles on  20m . Is the
superiority
 > > of the loop greatly exaggerated or am I missing something here?  I have
 > > written articles encouraging people to use lops instead of dipoles and
now
 > > wonder if I lead them astray!!!!
 > >
 > > Again...perfect resonance (checked witha  RF1 at the feed point, end of
a
 > > half wave section of coax and after matching with the 1/4 transformer
too! I
 > > can't see I have made any mistakes here! If its the height......how 
come
the
 > > inverted vee works MUCH better?
 > >
 > > Any thoughts. comments, advise?
 > >
 > > 73,
 > > Ron, 6Y5/4S7RO
 > >
 > >
 > >
 > > - - -
 > >
 > > Your moderator for this list is:
 > > Larry Wilson KE1HZ [email protected]
 > > _______________________________________________
 > > Antennas mailing list
 > > [email protected]
 > > http://mailman.qth.net/mailman/listinfo/antennas
 > >
 >
 > - - -
 >
 > Your moderator for this list is:
 > Larry Wilson KE1HZ [email protected]
 > _______________________________________________
 > Antennas mailing list
 > [email protected]
 > http://mailman.qth.net/mailman/listinfo/antennas

- - -

Your moderator for this list is:
Larry Wilson KE1HZ [email protected]
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