[Antennas] Loop vs Dipole

[Pastor-kc1di]

 Hi Ron,=0D
=0D
A couple of things that may be hindering the loop.  First if it's a detla
loop Three side Vs four.. and your feeding it any where near the appex yo=
u
will find that it is the sam as feeding a dipole at the height of the bot=
tom
wire.. that is because the delta loop acts like 1/2wave transmission line
when fed at the apex.. now this works ok if the delta is pointe up that i=
s
with long side up in the air but if the apex is at the top then you are
actually seeing most of the radiation at whatever height the longes side =
is
at.=0D
=0D
Go to W4RNL's great page it explains this much better than I can here.  =0D
You'll find it at:=0D
 http://www.cebik.com/gup/gup17.html=0D
and http://www.cebik.com/gup/gup18.html=0D
and http://www.cebik.com/gup/gup19.html=0D
=0D
hope this is of help.  =0D
Short take your loop may not be as good as your dipole because of the way=
 it
s configured.=0D
73 Dave KC1DI=0D
=0D
-------Original Message-------=0D
 =0D
From: Ron & Madhavi=0D
Date: Wednesday, October 01, 2003 1:16:50 PM=0D
To: antennas@mailman.qth.net=0D
Subject: [Antennas] Loop vs Dipole=0D
 =0D
Here's a tough one....or is it?!=0D
 =0D
I live in a townhouse in Kingston - the backyard is no more than 32' long=
=0D
and 10' wide, with a concrete parapet wall at the back.=0D
 =0D
I have a 25' tall aluminum pole clamped to the wall and ran an inverted v=
ee=0D
on 20m (25' at the apex). Results were fair and with my 850S, I worked in=
to=0D
Asia and more consistently into Europe.=0D
 =0D
Wanting to improve on it, I replaced the vee with a full wave loop and=0D
expected it to outperform the inverted vee. The loop has perfect resonanc=
e=0D
(a nice 1.1 SWR). The matching is done with a 1/4 75 ohm transformer.=0D
HOWEVER, even though I have tried to move the feed to a corner, 1/4 from =
a=0D
corner, center, apex etc., nothing seems to make it outperform the invert=
ed=0D
vee. I know that this does not confirm theory -- as the loop is larger, h=
as=0D
a lower take off angle (at least so they say!) and better SWR etc.=0D
Adddmitedly, the base of the delta is a FEW feet lower off the ground tha=
n=0D
the ends of the vee, but I expected the claimed superiority of a full wav=
e=0D
loop to offset that.=0D
 =0D
Used many 40/80m lops in the past, but never compared them to dipoles and=
=0D
vees at the same height! The results however were quite pleasing. First t=
ime=0D
I am running comparisons on loops and dipoles on 20m . Is the superiority=
=0D
of the loop greatly exaggerated or am I missing something here? I have=0D
written articles encouraging people to use lops instead of dipoles and no=
w=0D
wonder if I lead them astray!!!!=0D
 =0D
Again...perfect resonance (checked witha RF1 at the feed point, end of a=0D
half wave section of coax and after matching with the 1/4 transformer too=
! I=0D
can't see I have made any mistakes here! If its the height......how come =
the=0D
inverted vee works MUCH better?=0D
 =0D
Any thoughts. comments, advise?=0D
 =0D
73,=0D
Ron, 6Y5/4S7RO=0D
 =0D
 =0D
 =0D
- - -=0D
 =0D
Your moderator for this list is:=0D
Larry Wilson KE1HZ antennas-owner@mailman.qth.net=0D
_______________________________________________=0D
Antennas mailing list=0D
Antennas@mailman.qth.net=0D
http://mailman.qth.net/mailman/listinfo/antennas=0D
 =0D
=2E