Well first off its beautiful isn't it?
No, not your style? Well trust me it will grow on you when you finally put one up on a tower and you make some noise on the bands, and you realize you are able to hear a pindrop in Mongolia on your reciever.
Ok so what's the big deal? I would rather let some of the true experts tell you what the story is rather then open myself up to the long barrage of devoted Yagi afictionado's who will undoubtedly blitz me with nonsense. So first a short often repeated history lesson :
Back in 1951 Clarence Moore a Christian Missionary and engineer at a radio station high in the Andean mountains of Ecuador, developed a two loop antenna that he called a Quad. He developed this antenna to resolve issues caused by large coronal discharges while using a yagi beam antenna in the thin air of higher altitudes. These coronal discharges were periodically litterally Melting the Yagi antennas. His patent does include a mention and illustration of a two element unidirectional "quad", and describes the full wave loop concept. "Moore's design eliminated interference from coronal discharge. "End effect", which is inherent with the Yagi, is absent in a quad because its elements have no ends. But other advantages appeared. The higher impedance mentioned in the quote above translates to lower current and thus lower loss on the transmission lines, and gain is higher than that of a Yagi." Hey this is straight from Wikipedia...go look it up:
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Here we go Cubical Quad versus Yagi..........Advantages over a Yagi-Uda:
Rigorous testing of the quad antenna show the
following advantages over a Yagi-Uda antenna.
Polarization
It is easy to change polarization from vertical to horizontal.
Multiband antenna
It is easier to build a multiband quad antenna, than a multiband Yagi
antenna.
Higher gain
The 2-element quad has almost the same gain as a 3-element Yagi: about
7.5 dB over a dipole. Likewise, a 3-element quad has more gain than a
3-element Yagi. However, adding quad elements produces diminishing
returns. Quoting from William Orr, "Whereas parasitic beams having
twenty or thirty parasitic directors are efficient, high gain antennas,
it would seem ... that maximum practical number of parasitic loop
elements for the quad array is limited to five or six." (Orr, p. 48)
Radiation resistance
Radiation resistance is affected by antenna height above ground, element
spacing, and environmental conditions. However, values will be higher
than for a Yagi and more closely matched to a 50 Ohm coaxial feed.
Lower boom height
"A two-element, three-band quad, with elements mounted only 35 feet
above ground, will give good performance in situations where a triband
Yagi will not."[10]
Shorter boom
William Orr's book[11] shows a 10-15-20 meter, 2-element Quad with boom
length of 6′10″.
Internally stackable
Interaction between antennas of a multiband quad are quite low, even
when fed with a single feed line. (Orr, 1959, pg. 63)
Lower radiation angle
According to K0SR[12] the claim that quads "open the band earlier",
which suggests that they exhibit a lower angle of radiation than Yagis,
has persisted for 50 years in spite of the fact that computer models
disagree. He posits that the vertical sides of each element actually
radiate the low angle component.
Disadvantages compared to other antennas
Bandwidth
If tuned for maximum gain, the bandwidth for a 3-element quad antenna is
limited: Deviation from the design frequency will unbalance the
near-resonance condition of the parasitic elements. However, lengthening
the director elements, thereby sacrificing approximately 1 dB gain,
allows for much broader bandwidth.
Maintenance
A quad is a 3 dimensional antenna so maintenance can be difficult. Even
with a tilt over tower, tall ladders or a bucket truck may be needed.
There are devices that will allow the tilting of the tower to the ground
to work on a cubical quad antenna, rotator, or tower. It works by
letting the quad loops swivel out of the way. When the tower is in the
operational position the elements are locked into position (the locking
mechanism is powered by gravity).
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As for me, I have a few issues with some of these statements:
The part about diminshing returns I have a tough time believing that that is true, or why it would be.
Under disadvantages: The bandwidth with computer software today can be made as wide or a sharp as you want, yes it does effect gain somewhat, but Eznec models have shown this to be minimal on the order of tenths of a DB, not anywhere near 1 DB gain.
Under Advantages: Its easier to build a Multiband Cubical Quad then a Multiband Yagi.........NO it isn't...this is just wrong. its more difficult for sure.
Under disadvantages: The maintenance issue here on Wikipedia has been glossed over. The Cubical Quad does have maintenance issues. The wires get lots of attention from birds ( like birds sometimes hitting them at 30 mph ) goodbye wire. But more importantly for decades ICE and ICE Storms was the downfall of the Cubical Quad. This is still true, this combined with high winds ( a northeaster ) can make a Cubical Quad resemble a ball of Christmas lights that you used from last year pretty quickly. This has been addressed by Cubex and other Cubical Quad manufacturers, but mother nature is never completely tamed.
I also think, whats not mentioned is that the Cubical Quad is a BIG ANTENNA. As mentioned 3 dimensional but more importantly BIG. After all you are using double the size elements as a full size Yagi! And it will be a struggle to get it up and down cleanly every time you need to do maintenance.
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Ok Yagi owners, see I bashed it a little. You guys happy? No. Okay Well then your not gonna like this either:
I am a packrat, meaning I collect things I'm interested in to a fault. Its a personality trait I litterally have a tough time managing. So one of the things I have collected over the years as relates to this hobby is magazines and magazine articles and books. So as you are already thinking, I have collected virtually ever piece of written information I have ever seen on the Cubical Quad, starting with the QuadFather of Authors. The extremely smart Bill Orr. More on him in a minute
Ok back to Clarence Moore for a bit:
Well Clarence Moore went on to found International Radio and Electronics Corporation (IREC) in Elkhart, Indiana which was renamed Crown International in the 1960s at the suggestion of his wife Ruby. Crown International manufactured electronic devices including power amplifiers. Clarence armed with his new invention started entering dx contests. Clarence quickly got the attention of Lew McCoy a very Big Gun back in the 1960's. Lew was a "wide spaced" Yagi guy (typical of the times). Well Clarence and his new antenna toy, the Cubical Quad, was stealing all of the dx from Lew McCoy and his dx buddies, even though they were using 4 element Yagi's while Clarence was only using a 2 element Quad. Since Lew only lived 100 miles away from Clarence he and his buddies drove up there to see what was going on. It was then he then realized the superiority of the Quad after seeing is believing using Clarences radio equipment and talking with him. Lew McCoy then went to work as a technical advisor to the ARRL. Although he reported that the ARRL wasn't as enthusiastic about the Quad as he was (Somethings never change). Even though Lew stated to them emphatically that the Quad had 1.8 Db gain over a 1/2 wave dipole, and they should consider doing more articles about it. As he was employed by the ARRL occasionally he job was to monitor foreign broadcasts, he did this with another amateur operator there who used a comparably sized boom lengthYagi. Over a two year period and Thousands of stations monitored, 100% of the time the Quad heard the stations louder and first and later then the Yagi. If you would like to see this for your own eyes, pick up Lew McCoys excellent antenna book "Lew McCoy on Antennas" it was written not too long ago.
The story about Bill Orr "All about Cubical Quads" and the Quad basically repeats a similar story of that of Lew McCoy as he was also Big Gun and a ARRL technical contributor. Other Big Guns such as George McCarthy W6SUN "More about Cubical Quads"and John Koszeghy K2OB "The High performance Cubical Quad Antenna", and Big Big Gun Bob Haviland W4MB "The Quad Antenna" have also written good books about Cubical Quads and their advantages.
If you think this is older irrelevant information then I think you should listen to L.B. Cebik W4RNL (sk) he is the father of Eznec modeling and wrote 3 books about the Cubical Quad as well as thousands of online articles about other antennas. But his actual physical books were about Quads. Having spoken to Larry Cebik many times before he passed, he is most responsible for the widespread use of Eznec (I learned from him). rest in peace L.B. I miss you.
Want more? Well there have been over 50 articles written about Quads in CQ, 73, QST, Amateur Radio magazines over the years (I know I'm a packrat and have them all). Out of all the articles comparing a Cubical Quad to a Yagi in performance there is only ONE Article where the author choose to pick having a Yagi over the Quad. ONE. Whats not highlighted is the fact that in that article the Yagi had a 83% longer boom length then the Quad. 83% !!!! and it was a 5 element Yagi versus a 4 element Quad.
So if you need more punishment, you can check out a couple of these articles. There are dozens more just like them. All with the same conclusion. Cubical Quads beat Yagi's with the same boom length rather easily.
http://www.astrosurf.com/luxorion/qsl-antenna-comparison.htm
https://www.electronics-notes.com/articles/antennas-propagation/cubical-quad-antenna/quad-beam-antenna-reflector-director.php
http://ncjweb.com/features/janfeb08feat.pdf
http://www.rfcafe.com/references/qst/yagi-vs-quad-october-1966-qst.htm
(this is the one article where the author wasn't sure what to pick, but picked the Yagi, you decide looking at his own results if he made the right decision.)
BTW, as a side note Cubical Quad antennas were used during operation Desert Storm, because the Yagi's could not hear anything due to charged sand particles during sand storms. The quads were quiet.
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Ok so why doesn't everybody use them? :
Well as I said earlier there are times you would not use a Cubical Quad. Almost all of these reasons relate to mechanical reasons.
#1. You live in a zone where there are Big Ice storms during the winter or similar bad weather events ( high winds, Hurricanes, etc.) are frequent at your particular location.
#2. You abhor maintenance, which you may need one day on your Quad. If you want a low maintenance buy the excellent Mosley Yagi. Any of them, they'll last for 20 years +
#3.You are a Super Station and the stacking distance frankly between 10 -20 meter Cubical Quads is just too large. This is certainly very true, that and the maintenance and guy wire issues kill the Cubical Quad for Super Stations.
#4. You are afraid of what your wife and or neighbors would think. (how dare you try to fly a wire box kite in your backyard)
#5. The Quad you have to build yourself, even though it comes as a complete kit, thats just too difficult for you. (very true in these days of disposable everything)
#6. You had a Quad and loved it, but now you are just too old to maintain it. ( I have talked to 100's of people and this is their response). In fact no one I have ever talked to who actually had a Cubical Quad, ever said a bad word about the performance, in fact they all loved the performance.
#7. You would have to have real Friends at your house to help you get it up. ( sorry I can't help you with that ).
A word about Forums: Forums remind me alot of CB radio back in the day when I was a kid. You could litterally say anything on CB radio and nobody could really verify your existance. You could be the toughest kid in the town, the smartest kid in the town, the richest kid, etc, etc. Whatever you wanted to say no one could challenge you. You could with a few speech lessons come off as an expert of knowledge. Sound familiar?
Well on the amateur radio forums there are some people who are particularily good at this. They will have a comment about anything and everything, somehow trying to boost their ego, through social media. There is even a couple of super forum experts, that the printed words"Cubical Quad" will get an immediate response from them, as if they have it on their saved forum word list. (probably do somehow). These experts who can be very asute in most other matters of antennas and radios, will quickly pounce on you if you mention the word "Quad" as if they know all about them, bringing up techno jargon and words no one has ever seen, explaining why the Quad is no good, etc, etc. They will bring up lots of experience they have had with them, and yet can offer no pictures of any Quads they have actually built. BTW.. no one that I know of in 23 years has ever heard them on the air! Maybe they lost out to a big Quad one day on the air many years ago, who knows what the issue is?? But anyway I prefer to get my information from people I know, whom I am sure have actually built many antennas as well as some who have written actual published books about them.
But thats just me. So Forum Beware.
So I summary I would say this:
You are not afraid to build and test and make adjustments to your antenna
You don't live near the North Pole, or someplace with similar rotten weather most days
If you can only put up one antenna at your location, and you are primarily interested in 10 - 20 meter HF
You always wanted to be the Big Gun at least in your surrounding area and break pile-ups on 20 meters without using 1000+ watts
Well then the Cubical Quad is for you!
I have built a Cubical Quad Calculator for you here
