Chameleon Skyloop Antenna 4 sides (square or rhombic shape?) or 6 sides (honeycomb shape?)

  • 1
  • Question
  • Updated 4 years ago
I am sure there are technical and scientific studies on the wire loop antenna with 4 sides, squared and rhombic shaped; and 6 sides for a honeycomb shape. I am looking for those studies to read up on the propagational charicteristics of those shape.  I am buying a Chameleon Skyloop antenna, March 1st. Can anyone point me to those studies?

Thank you.
Photo of Don Hamrick

Don Hamrick

  • 45 Posts
  • 8 Reply Likes

Posted 4 years ago

  • 1
Photo of George Molnar, KF2T

George Molnar, KF2T, Elmer

  • 1681 Posts
  • 617 Reply Likes
I can't point you to any studies, but strongly suspect that in the real world any difference from number of sides will be overwhelmed by variations in the local environment. Placing the wire in the clear and as high as possible will improve things better than any geometric shape, I think.
Photo of Don Hamrick

Don Hamrick

  • 45 Posts
  • 8 Reply Likes
I know that to be true for any given antenna. I was a U.S. Coast Guard radioman (1975-1988) I am age 60 now. The proper step in selecting any antenna is to learn the theory and propagational aspects of the antenna before moving to the application of the antenna.

But I disagree with you on your implied irrelevance to the shape of the antenna. The radiating pattern of a 6-sided honeycomb antenna is different from a 4-sided square loop antenna. It is the radiating patterns of the two antennae I need to read up on before I buy and deploy the Skyloop antenna. Once you learn the radiating pattern of the antenna then you will have a better idea on were to place that antenna in the environment.

Supporting Evidence: Numerical Simulations of Radiation and Scattering Characteristics of Dipole and LOOP Antennas

The cited online article above is for engineers with a PhD in mathematics. I am looking for articles geared more for "operators" and less for PhD math geniuses. That's why I have to relearn the Smith Chart for starters, like RF Basics by Martin D. Stoehr, PMTS, ISM-RF Strategic Application.

It is better to know what you are doing through research and get the results you want in the application to what you have learned rather than just guess. That's my philosophy.

Don / KI5SS
(Edited)
Photo of Stan - VA7NF

Stan - VA7NF

  • 473 Posts
  • 119 Reply Likes

Your question caught my interest.  Ran an eznec model for each.

Square - 71feet per leg at 50 feet elevation:
80M - Straight up, no nodes or directional bias.  8db gain, 0db gain at 20 degrees
20M - 4 nodes with 12db gain at 20 degrees with nodes on the axis (centre fed) or at the diagonal (corner fed)

Hexagonal - 49 feet per leg at 50 feet elevation
80M - Same as square - Straight up dropping to 0db gain at 20 degrees
20M - 6 nodes with 11dg gain off the end of the feed wire at 20 degrees.  The other 4 nodes are 7db each.

Photo of Don Hamrick

Don Hamrick

  • 45 Posts
  • 8 Reply Likes
Now that's what I'm talkin' about! I found the Eznec Antenna Software website. The software for Eznec+ is $149. If there is a better Smith Chart program, even if more expensive I sure would like to know. I will still have to do my my book studies though.

See Smith Chart for Microsoft Visio. I have MS Visio Standard 2016.

The Chameleon CHA SKYLOOP antenna wire is 250 feet. That makes 62.5 feet per side for 4 sides of the square. And that makes 41.67 feet per side for 6 sides.

Can you run those dimensions? I will keep the numbers for reference.

Nothing comes easy.
(Edited)
Photo of Stan - VA7NF

Stan - VA7NF

  • 473 Posts
  • 119 Reply Likes
Certainly.  Please advise Elevation feet above ground, Frequency, Feed point % along one of the 4(6) wires - corner is 0% centre is 50% or other. 
Photo of Don Hamrick

Don Hamrick

  • 45 Posts
  • 8 Reply Likes
I am styling my Flex 1500 radio as an emergency radio for disasters but at the same time I will be using the radio for my own enjoyment in my travels when there are no disasters. I will be using it on all bands from 160 meters to 6 meters in all modes. The Chameleon Skyloop antenna is the perfect antenna to toss up with suspending lines with pulleys to slide along the antenna loop for the adjusting angles to about 30 to 50 feet of height using 60 feet of Ecoflecx 10 Plus coax cable for the Chameleon Skyloop antenna. The feed point will be in the corner of the octagon/honeycomb shaped antenna. Every instance of my use of the radio will be in a different location and height.
(Edited)
Photo of Norm - W7CK

Norm - W7CK

  • 762 Posts
  • 164 Reply Likes
I'm just curious as to why you'd buy an antenna that is really easy to build. 

If you have the space, you may want to expand the dimensions just a little bit and build a mega-loop.   Google "Mega Loop" and you'll come up with several comparisons between it and conventional horizontal loops.  Its basically a horizontal delta loop that is fed in one corner with a 4:1 balun.  I've just been reading about them the past 2 days.  I just wish I had enough space at my present QTH.  Anyway, the articles on the web should provide some great reading material.   Its lots of fun building wire antennas and it really doesn't cost much.  Plus you get to tell everyone its home built!
(Edited)
Photo of Don Hamrick

Don Hamrick

  • 45 Posts
  • 8 Reply Likes
I am not interested in constructing a DIY antenna. I am more interested in an off-the-shelf, ready to use, retail antenna. I want to spend my time using the antenna with my Flex 1500 radio rather than constructing and testing an antenna. The Chameleon Skyloop antenna already has a high power 4:1 air core balun (1000W CW) to match the loop to the coax cable. It has been inserted in a waterproof container at the feeding point of the antenna. That is all the construction about the antenna I need to know other then the technical propagation characteristcs of the antenna. An individual should not expect everyone to have the same interest as himself because everyone's lives, experiences, and activities are not the same. Where every amateur radio operator's interests do merge is for the primary purpose of disaster communications on amateur radio and the secondary purpose for everything else from simple fun, to contesting and (testing DIY antennae, which is not my preference) and the advancement of communications technology. That's called freedom.

My interest is using the new digital communications modes that did not exist in my era of Morse Code and RTTY as a U.S. Coast Guard radioman (1975-1981).
(Edited)
Photo of Norm - W7CK

Norm - W7CK

  • 762 Posts
  • 164 Reply Likes
Regardless of whether you plan on building or buying the Chameleon, please check out the mega-loop information on the web.  One of the unique properties of the mega-loop is its gain , radiation pattern, and propagation characteristics.  This is due to the perfect horizontal triangle layout of the loop along with its feed point being in any one of the 3 corners.   It appears that the triangle configuration lowers the radiation angle and gives a slight bit of additional gain opposite the feed point when the operating frequency is higher than the fundamental design frequency.  In other words, when you are operating the antenna on a harmonic of the frequency that the antenna was originally designed for. 

I think you'd enjoy reading about them and maybe get a better understanding of how the different loop layouts affect radiation patterns.  I found it pretty fascinating.  Antenna design hasn't really changed much over the years.  Actually the basics have been with us for a long long time.  Almost every antenna out there is either a dipole, vertical or loop - some with multiple elements.  Now that we have access to modeling software, folks are starting to change the configuration of these designs to see how it effects gain and radiation patterns.  Occasionally someone comes up with results that can be used to an advantage in some installations.  I think the mega-loop which is nothing more than a large
horizontal equilateral triangle loop fed at one corner is well worth investigating.
Photo of Don Hamrick

Don Hamrick

  • 45 Posts
  • 8 Reply Likes
3 SIDES? Triangle? Hmmm. That is interesting. I completely overlooked that possibility. Throw the URL links at me! I will definitely check them out.
Photo of Norm - W7CK

Norm - W7CK

  • 762 Posts
  • 164 Reply Likes
A quick Google came up with these:

http://www.m0xxt.co.uk/index.php?option=com_content&view=article&id=68&Itemid=68

https://www.youtube.com/watch?v=SOvhetU1_ps

http://www.m0mcx.co.uk/tag/megaloop/


http://www.m0mcx.co.uk/xxt-mega-loop-update/

I have modeled the antenna just like you see demonstrated in the youtube video referenced above.  It does show a lot of promise!

I only wish I had the room to put one up and give it a try.