Cophasing Two Full-Wave Loops?
 

Hello everybody,

I hope everyone had a very Happy Easter. I have a spare 2:1 current
balun and would like to use it to feed a vertically oriented single-
band full-wave loop. I began to wonder; Can one feed two vertically
oriented full-wave loops perpendicular to each other with a common
feed point? Any opinions? Thanks in advance. As always, take care
es...

Vy 73 de Bert
WA2SI

Cophasing Two Full-Wave Loops?
 

Can one feed two vertically oriented full-wave loops perpendicular to each other with a common feed point?

Many have.

73's
Richard Clark, KB7QHC

Cophasing Two Full-Wave Loops?
 

On 7 abr, 01:47, WA2SI wrote:
Hello everybody,

I hope everyone had a very Happy Easter. I have a spare 2:1 current
balun and would like to use it to feed a vertically oriented single-
band full-wave loop. I began to wonder; Can one feed two vertically
oriented full-wave loops perpendicular to each other with a common
feed point? Any opinions? Thanks in advance. As always, take care
es...

Vy 73 de Bert
WA2SI

Hello Bert,

When you have identical loops, with same orientation, and distance
between them is less then 0.2 lambda, you can connect them in
parallel. Current in both loops will be the same (magnitude and
phase) and far field radiation pattern will also not change (with
respect to a single loop).

When the distance between the loops wire diameter, you will
experience an increase in useful bandwidth. Impedance at current
nodes will not change that much, but impedance at voltage nodes will
reduce. Due to the mutual coupling, you will experience some drift in
resonant frequency.

Feeding in opposite phase will give a complete new radiation pattern,
significant reduction in useful bandwidth and possibly reduction in
radiation efficiency.

Best regards,

Wim
PA3DJS
www.tetech.nl
in case of PM, don't forget to remove abc from the address.

Wonderful!

Cophasing Two Full-Wave Loops?
 

On Apr 6, 6:47*pm, WA2SI wrote:
Hello everybody,

I hope everyone had a very Happy Easter. I have a spare 2:1 current
balun and would like to use it to feed a vertically oriented single-
band full-wave loop. I began to wonder; Can one feed two vertically
oriented full-wave loops perpendicular to each other with a common
feed point? Any opinions? Thanks in advance. As always, take care
es...

Vy 73 de Bert
WA2SI

I am taking your question as, 2 vertical loops, both hung from the
same skyhook, one broadside north/south, and the other broadside
east/west, and fed at the same point.

You get a more omni radiation pattern, but not full omni, there are
still lobes. This is much like 2 crossed dipoles (for the same band)
in an "X" configuration. Depending on height, you may not need the
2:1 balun. Check your impedance, a coax wound balun for a choke
may be all that is necessary.

73....Walter - K5EST

Cophasing Two Full-Wave Loops?
 

On Tue, 13 Apr 2010 09:59:08 -0700 (PDT), JIMMIE
wrote:

Ive never seen them connected in parallel

We have talked about them at length here. What was described is a
quadrifilar helix - without the helix.

As there are so many details of construction are missing, little more
can be said, and our original poster appears to have gotten bored with
the topic.

73's
Richard Clark, KB7QHC

Cophasing Two Full-Wave Loops?
 

On Tue, 13 Apr 2010 11:23:00 -0700 (PDT), Wimpie
wrote:

When you put them 90 degr. to each other (for example E/W and one N/
S), you will not get an omni-pattern. In that case you must make them
both off-resonance to get 90 degr phase time shift in generated fields
(or use a 90 degr. phase shifter and feed them separately).


Hi Wim,

You can do it with a goniometer. This antenna was first described 103
years ago by Bellini and Tosi.

73's
Richard Clark, KB7QHC

Cophasing Two Full-Wave Loops?
 

On Apr 13, 1:36*pm, Richard Clark wrote:
As there are so many details of construction are missing, little more
can be said, and our original poster appears to have gotten bored with
the topic.

73's
Richard Clark, KB7QHC

Hello agn, everybody:

My apologies to you all. No, I have not gotten bored with this topic.
My job has rotating schedules as well as mandatory overtime.
Unfortunately, when one gets "stuck" for o/t, it's usually for an
entire extra 8-1/2 tour. When I finally get home, (A nice hike, btw!)
I either attend to my familial obligations or just crash. I did manage
to work a 5R8 station on the bottom of 80 so all was not lost - hihi.

I was thinking of making use of some unused space on my 50' fiberglass
mast by mounting a 2:1 balun and having two 10m vertically polarized
delta loops sharing the same feed points, specifically the
aforementioned balun. Yes, the goal is a single band, quiet and
physically unobtrusive single-band omni-directional. (Or at least
somewhat omni-directional without being a cloudburner.) Visualize, if
you will, two wire Christmas tree shaped wire loops, 90 degrees from
one another, fed at the center of their bottom legs up abt 30'.

Some might say, "why not just mount a vertical?" Well, I have the 2:1
balun and I figured that the loop would be much quieter.

Thanks so much for all your responses and have a safe and wonderful
weekend. Take care es...

Vy 73 de Bert,
WA2SI

Cophasing Two Full-Wave Loops?
 

On Apr 17, 8:06*am, WA2SI wrote:
On Apr 13, 1:36*pm, Richard Clark wrote:

As there are so many details of construction are missing, little more
can be said, and our original poster appears to have gotten bored with
the topic.

73's
Richard Clark, KB7QHC

Hello agn, everybody:

My apologies to you all. No, I have not gotten bored with this topic.
My job has rotating schedules as well as mandatory overtime.
Unfortunately, when one gets "stuck" for o/t, it's usually for an
entire extra 8-1/2 tour. When I finally get home, (A nice hike, btw!)
I either attend to my familial obligations or just crash. I did manage
to work a 5R8 station on the bottom of 80 so all was not lost - hihi.

I was thinking of making use of some unused space on my 50' fiberglass
mast by mounting a 2:1 balun and having two 10m vertically polarized
delta loops sharing the same feed points, specifically the
aforementioned balun. Yes, the goal is a single band, quiet and
physically unobtrusive single-band omni-directional. (Or at least
somewhat omni-directional without being a cloudburner.) Visualize, if
you will, two wire Christmas tree shaped wire loops, 90 degrees from
one another, fed at the center of their bottom legs up abt 30'.

Some might say, "why not just mount a vertical?" Well, I have the 2:1
balun and I figured that the loop would be much quieter.

Thanks so much for all your responses and have a safe and wonderful
weekend. Take care es...

Vy 73 de Bert,
WA2SI

I ran a single loop like you are talking about on 10M and had to use a
75 ohm 1/4 wl transformer to match the approximately 100 ohm impedance
of the loop.

I would think the two antennas mounted at right angles to each other
should be a pretty good match for 50 ohms.

Jimmie

Cophasing Two Full-Wave Loops?
 

On Apr 17, 8:06*am, WA2SI wrote:
On Apr 13, 1:36*pm, Richard Clark wrote:

As there are so many details of construction are missing, little more
can be said, and our original poster appears to have gotten bored with
the topic.

73's
Richard Clark, KB7QHC

Hello agn, everybody:

My apologies to you all. No, I have not gotten bored with this topic.
My job has rotating schedules as well as mandatory overtime.
Unfortunately, when one gets "stuck" for o/t, it's usually for an
entire extra 8-1/2 tour. When I finally get home, (A nice hike, btw!)
I either attend to my familial obligations or just crash. I did manage
to work a 5R8 station on the bottom of 80 so all was not lost - hihi.

I was thinking of making use of some unused space on my 50' fiberglass
mast by mounting a 2:1 balun and having two 10m vertically polarized
delta loops sharing the same feed points, specifically the
aforementioned balun. Yes, the goal is a single band, quiet and
physically unobtrusive single-band omni-directional. (Or at least
somewhat omni-directional without being a cloudburner.) Visualize, if
you will, two wire Christmas tree shaped wire loops, 90 degrees from
one another, fed at the center of their bottom legs up abt 30'.

Some might say, "why not just mount a vertical?" Well, I have the 2:1
balun and I figured that the loop would be much quieter.

Thanks so much for all your responses and have a safe and wonderful
weekend. Take care es...

Vy 73 de Bert,
WA2SI

I ran a single loop like you are talking about on 10M and had to use a
75 ohm 1/4 wl transformer to match the approximately 100 ohm impedance
of the loop.

I would think the two antennas mounted at right angles to each other
should be a pretty good match for 50 ohms.

Jimmie

Cophasing Two Full-Wave Loops?
 

On Sat, 17 Apr 2010 05:06:42 -0700 (PDT), WA2SI
wrote:

Visualize, if
you will, two wire Christmas tree shaped wire loops, 90 degrees from
one another, fed at the center of their bottom legs up abt 30'.

Hi Bert,

This is the design of Bellini and Tosi of 105 years ago. They fed it
through a goniometer so they could steer the beam angle. At the time
they were unconcerned with load Z as you could tune the final and
drive to accomodate that.

Some might say, "why not just mount a vertical?" Well, I have the 2:1
balun and I figured that the loop would be much quieter.

I'm not sure how you have come up with, or plan to come up with a 2:1
BalUn - not very common, and construction details may ruin
expectations for performance.

As for "quieter," that is a very common myth = t'ain't so.

As for other details, you only roughly describe the length of wire
involved (in only one dimension) and you say nothing of frequency -
except by inference in the 80M band. Such details impact Z
considerably if you want someone to supply you with that
characteristic.

73's
Richard Clark, KB7QHC

Cophasing Two Full-Wave Loops?
 

On Apr 17, 11:53*am, Richard Clark wrote:
I'm not sure how you have come up with, or plan to come up with a 2:1
BalUn - not very common, and construction details may ruin
expectations for performance.

I already have the 2:1 BalUn on hand. It is a Balun Designs offering.
The link is supplied below.

http://www.balundesigns.com/servlet/...uns/Categories

As for "quieter," that is a very common myth = t'ain't so.

Drats! I suppose I'll just have to hope for the best.

As for other details, you only roughly describe the length of wire
involved (in only one dimension) and you say nothing of frequency -
except by inference in the 80M band. *Such details impact Z
considerably if you want someone to supply you with that
characteristic.

I want this to be a 10m semi-omnidirectional antenna. (Clover leaf
pattern I'd guess. Omni enough fo me.) My reference to 80m was just a
passing statement re. my schedule. Take care es...

Vy 73 de Bert
WA2SI

Cophasing Two Full-Wave Loops?
 

On Apr 17, 7:06*am, WA2SI wrote:

Yes, the goal is a single band, quiet and
physically unobtrusive single-band omni-directional. (Or at least
somewhat omni-directional without being a cloudburner.) Visualize, if
you will, two wire Christmas tree shaped wire loops, 90 degrees from
one another, fed at the center of their bottom legs up abt 30'.

If I'm understanding this, what you are proposing would actually be
horizontally polarized, not vertical.
I imagine the triangle shape distorts things, but in general if you
feed a loop at either the top or the bottom, it will be horizontal.
You want to feed from one of the sides for it to be vertical.
Which calls for a square for most people..
Actually, what you want to build is very common. Most refer
to them as an "eggbeater". The usual method of feeding the
elements is 90 degrees out of phase if I remember right.
That gives the most omnidirectional pattern.


Some might say, "why not just mount a vertical?" Well, I have the 2:1
balun and I figured that the loop would be much quieter.

As Richard mentioned, this is fiction. All antennas receive noise.
How much you receive depends on the polarity of the antenna, the
noise source, and the efficiency of the system. It's quite possible
for
the horizontal antenna to receive the most noise if the noise is
radiated from a horizontal source. It's possible for an antenna to be
very "quiet" if it's very inefficient. Actually, if I notice an
antenna that is
too "quiet" I start to wonder what the heck is wrong with it.. :/
Noisy is good. Maybe not the noise itself, but that you receive it
well is good. You don't want it any other way, unless maybe you
are a proponent of the Unwintennas which tend to be air cooled
dummy loads.. :(

A good elevated vertical is actually a very good 10m antenna.
It's good for DX, but it's also good for space wave coverage to
locals.

Cophasing Two Full-Wave Loops?
 

On 17 abr, 14:06, WA2SI wrote:
On Apr 13, 1:36*pm, Richard Clark wrote:

As there are so many details of construction are missing, little more
can be said, and our original poster appears to have gotten bored with
the topic.

73's
Richard Clark, KB7QHC

Hello agn, everybody:

My apologies to you all. No, I have not gotten bored with this topic.
My job has rotating schedules as well as mandatory overtime.
Unfortunately, when one gets "stuck" for o/t, it's usually for an
entire extra 8-1/2 tour. When I finally get home, (A nice hike, btw!)
I either attend to my familial obligations or just crash. I did manage
to work a 5R8 station on the bottom of 80 so all was not lost - hihi.

I was thinking of making use of some unused space on my 50' fiberglass
mast by mounting a 2:1 balun and having two 10m vertically polarized
delta loops sharing the same feed points, specifically the
aforementioned balun. Yes, the goal is a single band, quiet and
physically unobtrusive single-band omni-directional. (Or at least
somewhat omni-directional without being a cloudburner.) Visualize, if
you will, two wire Christmas tree shaped wire loops, 90 degrees from
one another, fed at the center of their bottom legs up abt 30'.

Some might say, "why not just mount a vertical?" Well, I have the 2:1
balun and I figured that the loop would be much quieter.

Thanks so much for all your responses and have a safe and wonderful
weekend. Take care es...

Vy 73 de Bert,
WA2SI

Hello Bert,

When it is quieter and isn't a dummy load, it is more or less a
cloudburner. The reason for more noise is mostly caused by less
elevation of the main lobe due to the interference from the ground
reflection. This is what you want for line-of-sight and DX.

The vertical is a good option for sky wave and line-of-sight. When
you make it electrically a half wave, requirements for ground are very
limited. The only disadvantage is the matching section as the
impedance at half wave resonance is rather high (up to 1 kOhm for thin
conductors). When you run high power, you have to evaluate your
construction for corona discharge.

Maybe you can use parts from CB antennas.

Best regards,


Wim
PA3DJS
www.tetech.nl
in case of PM, please don't forget to remove abc