delta loop or di-pole ?
pws
I have a few days off in November and want to play antennas in the rain :)
I want to build an antenna for 17m.
I understand a delta loop will in theory have about 3db gain over a di-pole.
but does this mean the gain will be in a direction at the expense of another
direction ?
Is it best to have the delta loop radiating vertically or horizontally ? I
want to work a bit of DX...hopefully.
I will be feeding the coax with some heavy duty westflex 50ohm cable.
has anyone had any experience with this??
73's
Paul mw0dct
KA9CAR
http://www.cebik.com/radio.html
LB has some interesting articles on Dipoles vs Delta Loops.
As I recall his conclusion is that a dipole, at the same elevation as the
top of a delta loop, will work better than the delta loop.
Good luck making a choice.
KA9CAR
pws <p.g...@ntlworld.com> wrote in message
news:AdeC7.5345$mo.4...@news6-win.server.ntlworld.com...
Larry Gauthier
But, if you must decide on one versus the other, _and_ DX is your goal, then
the low angle of radiation presented by a vertical full-wave delta loop
should outperform the dipole.
To achieve vertical orientation, cut a full wave of wire, fold it into an
isosceles triangle with one leg vertical, and feed the vertical side 1/4
wavelength down from the top point. The feedline will need a 2:1 balum,
which can be accomplished with tightly-wrapped loop of 1/4 wave of 75 ohm
coax (electrical quarter wave = multiply the length time the velocity
factor of the 75 ohm cable) and feed it with any length of 50 ohm coax.
You should also find that this vertical-fed loop is less directional than
your dipole... which may or may not be an advantage. ;-)
-larry
K8UT
"pws" <p.g...@ntlworld.com> wrote in message
news:AdeC7.5345$mo.4...@news6-win.server.ntlworld.com...
Mark Keith
> I have a few days off in November and want to play antennas in the rain :)
>
> I want to build an antenna for 17m.
> I understand a delta loop will in theory have about 3db gain over a di-pole.
More like 1.5 to 2 db I bet.
> but does this mean the gain will be in a direction at the expense of another
> direction ?
Yes. Anytime you have gain in one direction, you have a deficit in
another direction.
> Is it best to have the delta loop radiating vertically or horizontally ? I
> want to work a bit of DX...hopefully.
Probably doesn't matter a whole lot on 17m. Some ways of feeding do
have better patterns. You could model them to see. A dipole would work
fine. MK
vt...@hotmail.com
>> but does this mean the gain will be in a direction at the expense of another
>> direction ?
>
>Yes. Anytime you have gain in one direction, you have a deficit in
>another direction.
Well, yes, but that direction that experiences the deficit might be
straight up or straight down, in which case you can still have an
omnidirectional pattern, with gain, in the horizontal plane.
That of course is how gain-type vertical antennas get their gain,
ve7rz
others were using 100+ watt base stations and yagis. The 2 loudest people on the
band were running 50 watts and delta loops about 15-20 feet in the air. I use one
on 40 and it is a hot performer. Try one.
Trace VE7RZ
vt...@hotmail.com
>I recently worked a pile of people on 10m. SOme were running 25 watt mobiles,
>others were using 100+ watt base stations and yagis. The 2 loudest people on the
>band were running 50 watts and delta loops about 15-20 feet in the air. I use one
>on 40 and it is a hot performer. Try one.
I have recently bought the ARRL Antenna Book and the ARRL Handbook,
and neither of them discuss delta loops at all. The Antenna Book does
discuss other types of loops ... round, square, octagonal, and
horizontal and vertical. Do delta loops have about the same
characteristics?
I have a dead tree trunk out in the back yard that is about 35 feet
high. I could put up a delta loop with one side going up the tree
trunk and the other two sides going off to the side, so that I'd have
a sideways isosceles triangle. The one side would be about 25 feet
and the other two sides (for a full wave loop on 40 or a half wave
loop on 80) would be about 50 feet. The apex angle would be pretty
sharp (I don't remember enough of my high school trig to figure it out
but I could find something in which to look it up).
Does that sound like it would work well? Where would I feed it for
best results?
Eamon Skelton
> hi all,
> I have a few days off in November and want to play antennas in the rain
> :)
>
> I want to build an antenna for 17m.
> I understand a delta loop will in theory have about 3db gain over a
> di-pole.
A delta-loop or a quad will have 3 to 3.5 dB gain over an isotropic
radiator (if you can find one) - thats just over 1dBd.
Below: my attempt at modelling a resonant dipole, quad and delta-loop with
NEC2.
Freq: 300MHz Wire 2mm. Antenna in free space.
Dipole: 2.14dBi. 72.03 +j0.6 Ohms. -3dB beamwidth 76 deg.
Delta: 3.09dBi. 126.6 =+j0 Ohms. -3dB beamwidth 82 deg.
Quad: 3.47dBi. 135.5 +j0.7 Ohms. -3dB beamwidth 82 deg.
The calculated gain of the dipole is very close to the
often quoted figure of 2.15dBi. I can't be sure of the
accuracy of the quad or delta-loop models, but the
numbers look reasonable to me.
Are we overdue for a quad vs delta vs Yagi flame war?
73, Ed. EI9GQ.
--
Remove 'X' to reply.
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Linux 2.4.13
George, W5YR
it seems to be a poor payback for the time and effort to build a
two-element quad to gain less than 1.5 db over a dipole. Of course, one
must consider the importance of F/B, etc.
Just out of curiosity, how did the quad show more forward gain than the
dipole but with a wider main lobe?
--
72/73, George W5YR - the Yellow Rose of Texas QRP-L 1373 NETXQRP 6
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe SOC 262
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
Icom IC-756PRO #02121 Kachina #91900556 IC-765 #02437
Eamon Skelton
> Don't see the basis for much disagreement, Eamon, other than to note that
> it seems to be a poor payback for the time and effort to build a
> two-element quad to gain less than 1.5 db over a dipole.
It's just a single quad loop. A two element quad (cubical quad) would
have more gain.
JLB
> I have a few days off in November and want to play antennas in the rain :)
>
In my experience antennas work better if you put them up in a driving
snow. Anyone else tested this theory?
Jim
N8EE
Mark Keith
I've heard that, but never tested. It rarely snows here. So rare in
fact, I'd probably rather go build a snowman than work on antennas in
that case. MK
GUY
the loop is quieter ,
Helmut Wabnig
<guylang...@gmail.com> wrote:
w.
Julian Macassey
old post. People using usenet via goggle do this all the time and
contribute nothing of any worth.
Julian Macassey
--
For both parties as the record makes clear, are the champions of
big business. The Republican platform admits it. The Democratic
platform attempts to conceal it. - Henry Wallace 1948
wicklowham
Perhaps an ancient message "re-gurgled" but at least a(ny) message on
this NG for a loooong time
Frank , EI7KS
Jeff Liebermann
<jul...@n6are.com> wrote:
>On Mon, 10 Apr 2023 12:48:25 -0700 (PDT), GUY <guylang...@gmail.com> wrote:
>
> There is nothing more fun than commenting on a 21 year
>old post. People using usenet via goggle do this all the time and
>contribute nothing of any worth.
located in Capetown, South Africa.
NNTP-Posting-Host: 102.222.180.149
Google Groups shows the article date quite clearly when replying.
Therefore such zero value postings are probably not accidental.
>> On Monday, October 29, 2001 at 10:45:28?PM UTC+2, Mark Keith wrote:
>>> jim.bo...@lintek.aeroflex.com (JLB) wrote in message news:<8d5ec8a2.01102...@posting.google.com>...
>>> > "pws" <p.g...@ntlworld.com> wrote in message news:<AdeC7.5345$mo.4...@news6-win.server.ntlworld.com>...
>>> > > hi all,
>>> > > I have a few days off in November and want to play antennas in the rain :)
>>> > >
>>> >
>>> > In my experience antennas work better if you put them up in a driving
>>> > snow. Anyone else tested this theory?
>>> >
>>> > Jim
>>> > N8EE
>>> I've heard that, but never tested. It rarely snows here. So rare in
>>> fact, I'd probably rather go build a snowman than work on antennas in
>>> that case. MK
>>
>> I compared a dipole and a loop , why i prefer the loop over the dipole ?
>> the loop is quieter ,
Jeff Liebermann je...@cruzio.com
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558
John S
--
Rumors of my retirement have been highly exaggerated.
