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Reviews Categories | Antenna Switching, Phasing, Controllers | Comtek 4-Square Systems Help


Reviews Summary for Comtek 4-Square Systems
Comtek  4-Square Systems Reviews: 15 Average rating: 5.0/5 MSRP: $319.95-349.95
Description: Comtek has manufactured the ACB-4 series of 4-Square Phasing Systems since 1990. Incorporating many improvements since 1994, the ACB-4 "Collins" series produces up to 5 dB gain and 20-25 dB Front to Back in a properly constructed 4-Square array. Available from 10 meters to 160 meters in single band models. More information available at www.comteksystems.com
Product is in production.
More info: http://comteksystems.com
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WZ7I Rating: 5/5 Apr 24, 2004 19:47 Send this review to a friend
Quite satisfied with 80 M array  Time owned: 6 to 12 months
Well, this system has been in use one winter season so I think I know enough to comment.

Last summer I installed a 4 square array of Hygain Hytowers. (for review see http://www.eham.net/reviews/detail/2238 ) I used the Comtek 4 square phasing box and Jimís premeasured phasing lines. This array has 60 radials per element with the all the joints where the radials cross each other brazed with copper / phosphorus rod. The array is 500 feet from the house and is fed with LMR-600 cable.

I had a 40 M 4 square array at another QTH with a phasing box made by another manufacturer that did not seem to work quite as well. I fussed and fussed with the 40 M array and was never entirely satisfied. I decided that I would just install this Comtek array and use it without worrying about it. We were careful in its installation but not compulsive. There are some trees that are probably too close but I donít want to cut more of them.

Some of my acquaintances have questioned the investment. I needed to use a contractor to do most of the installation so the cost was in the ball park of a 2 element yagi and guyed tower. But, I live on a wooded lot where towers are limited to 55 feet. In addition, there is very little that can go wrong with this array. I donít have to climb to maintain it. There are no mast bearings to bind when the wind blows and there are no guy wires for trees to fall on. Low maintenance and reliability are more important to me than ultimate performance.

But how does the array perform? I am entirely satisfied. It brings me real joy. I can make QSOs that would be impossible with a dipole. The gain helps to hold the circuit longer when conditions degrade. Often, the big advantage is the lower noise floor that a directional antenna gives.

Even if I relocated to an area that did not limit tower height I would put up another Comtek 80 M four square with HyGain HyTower elements.
 
NI1N Rating: 5/5 Jan 3, 2004 03:29 Send this review to a friend
I'm as happy as can be!  Time owned: 0 to 3 months
I'm currently living in the south-western part of Virginia because of a good job here. But, I don't plan to stay. So, I was looking for something with some gain and directivity that would be relatively easy to remove in a couple of years without leaving permanent damage to the property. I've heard the big boys using four squares on 80, so I figured I'd give it a try on 20.

First, Jim at Comtek was a pleasure to deal with. He had a lot of advice for the construction of the system. The manual that comes with the array controller is loaded with information, but Jim is also just a phone call away if you have any questions.

For the 16 foot verticals, Jim recommended starting with 1.5-inch tubing at the bottom (total of 3 sections, going up to 1.25-inch at the top). I thought that was a bit of overkill, but figured I'd follow his recommendation and am I ever glad I did. These verticals are rock solid. I can hold them sideways on the end and they don't even bend. They are in the ground 2 feet, which is enough to support them. But, for added strength I attached Phillystran guys at the 7-foot level. I think my house would blow away before these verticals even bent in the wind!

Installing the radial system was a monumental task of course. Based on my previous experience with verticals, I went with 4/10-wavelength radials, with 120 of them under each vertical. Its a lot of work, but I knew it would pay off.

Its not stacked 6-element monobanders, but it sure does work well. In the recent CQ WW DX CW contest, I was right behind the big guys and even beat some of them out for some multipliers. I had a grin from ear-to-ear when I heard BN0F in Taiwan calling me back after my 2nd call, knowing that there were dozens of other stations calling, and knowing that many of them are "contest superstations". That happened quite a few times during the contest for stations like JT1, XU7, and 9M4.

Unfortunately I don't have the room for the radials for an 80 meter system. But, I plan to put up 4-squares for 10, 15, and 40 meters in the spring.
 
AB8NU Rating: 5/5 Feb 8, 2003 14:33 Send this review to a friend
Works as Advertised- Great Performance!  Time owned: 6 to 12 months
I live on three and one-half acres of wooded land and have often wondered over the years how I would ever make use of it all. Then in early 2002 I decided to attempt setting up my first four-square for 20M. Going into this project I knew very little about four-square phased arrays.I learned about Comtek Systems products from a well known antenna manufacturer and then decided to contact Comtek. I knocked on Comtek's door as a four-square phased array novice and have learned enough to become a seasoned four-square veteran.

Jim Miller at Comtek guided me through the entire process and provided me with the answers that I needed. His solution provided me with a turn-key four-square phased array system with quarter-wave 20M Vertical Antennas. I was able to purchase most of the components that I needed directly from him which included Comtek's ACB-4 Four-Square Hybrid Phasing System and controller, cables, vertical antennas, radial wire and more. The only things that I needed to purchase locally were the mounting poles for the antennas and bobby-pins for the ground radial system.

His documentation for the ACB-4 Hybrid is extensive and provides the answers to most any questions that you may have about his system and then some. If the answer isn't provided in the documentation, he'll give you the answer your seeking if you contact him, and sometimes you'll even learn that the answer to the question that you're asking is already contained in the documentation and you just didn't find it. In addition if there's a problem, he stands behind his product with the service you'll need to solve the problem.

Construction and installation of the entire system is pretty straight forward. The most difficult part of the entire process for me was constructing the ground radial system. You'll need to do a little engineering on your own and be proficient at basic Trigonometry to determine how to accurately layout and construct the ground radial system. I can guarantee you that if the ground radial layout works out on accurately on paper, it'll work out correctly in the field exactly to the specifications that you have engineered on paper. It's remarkable and rewarding when everything just falls right into place and everything is symmetrical when you lay down the last piece of copper wire. This took some effort on my part with alot of wasted time and material until I did the math. Intuitive solutions just don't work. You've got to do the math.

Comtek recommends using a minimum of 60 copper ground-radial wires per antenna. Installing the 240 ground-radial wires to complete the entire ground-radial system is a monumental task. You'll need literally thousands of bobby-pins to attach the copper radial wires to the ground. I would recommend finding a hair and beauty supply store that the hair professionals buy from and purchase the bobby-pins by the pound for the best and most cost effective pricing.You'll use them up quickly. I was lucky enough to find them on sale when I needed them and ended up buying out their entire stock. I think that the women at the store are still wondering how we could use up all of the bobby-pins that were purchased.

Comtek stresses that the performance of it's four-square vertical phased-array system is highly dependent upon the installed ground-radial system and not to cut any corners with repect to this aspect of the project. It's tedious and grueling work to complete the ground-radial system, but the results in the end are well worth the effort. When have your first 5000 plus mile QSO into a country that you've never worked before, receiving an enthusiastic 59+ signal report while using 250 watts of power out, that's when you discover the real rewards of all of your efforts and time you have spent to do have done it the right way! The is the way Comtek recommends that you do it in the first place. In addition, my worst case power drop on 20M is 1%. The efficency of the system is 99%+ across the entire useable band! I don't end up melting snow in the Winter.

The 20M four-square worked so well that I decided to install an 80M quarter-wave four-square in the Fall of 2002. Again, Comtek provided me with a complete system that delivered the performance I've been seeking. Now I'm planning on installing a four-square for 160M in the Spring of 2003 and for the third time I went to Comtek with the challange for my location and Jim Miller was again able to provide me with the answers I needed for a solution for this band. I've learned to trust his in abilities and recommendations.

This system provides super front-to-back perfomance results. Another benefit is that you don't need to wait for your antenna rotor to change its direction of orientation when using this system. I equate it to a stealth type of technology, it's very advanced. I often turn the switch of the phasing system control box, which controls the orientation of the four-square, and toggle between two-sides of a QSO taking place. For example from 50 degrees to 140 degrees. By the way, an orphan of the 20M four-square is a useable system for 17M and with the 80M system you'll also have a useable system for 40M. On 160M you just get 160M.

Sometimes to have a little fun, I connect my SGC SG-2020 to one of the four-squares and answer a CQ using just five watts of power out. I can say that people are often quite amazed to learn that I'm QRP when the distance is 800 miles or more. I'm amazed!

Now that I've had the opportunity to use both of my four-squares extensively, I'm really happy that I chose to go for the 80M when I installed the second four-square system, based on Comtek's recommendation of the changing solar cycles. There are now times that 20M is kind of quiet at night when 80M is very active . In addition, I've learned of and have spoken with many other Hams who are using the Comtek system on-the-air. After a QSO of this type, it leaves you with a sense of pride of ownership and being a member of a family of Comtek product users. There are nights when it seems that the only other stations getting through when DXing are those that are using the Comtek four-square system! The Comtek system has been a cost effective performance driven solution for all of my needs.

What else can I say except that I no longer wonder what I'm going to use all of my land for and wish that I had a little more land available to install a 30M four-square. By the way, all of the trees aren't a problem either.
 
W1TE Rating: 5/5 Dec 20, 2002 09:24 Send this review to a friend
Excellent Product & Service  Time owned: 3 to 6 months
When I started expanding the transmit side antenna system on the low bands I decided to try a 4-Square on 80M and 40M. I chose the Comtek 4-Square phasing boxes based on comments from other users. I was pleasantly surprised with the results. The company communication was excellent, their included reference material was complete and the items were delivered immediately. The quality of workmanship was very good. The installation of the 40M 4-Square went exactly as planned. The 80M was downsized due to personal time constraints to a pair of verticals which also works as expected.

I will not hesitate to purchase the 30M version of this in the near future to improve that band.

The man behind this company has supported the contesting and DXing community with 4-Square hardware for years. He has been there and I expect he will be there when you need him.

Overall I am very pleased.

Charley W1TE
> 2250 DXCC Challenge Entities Confirmed
 
N0AH Rating: 5/5 Aug 29, 2000 10:54 Send this review to a friend
40/80 both work great!  Time owned: more than 12 months
Comtek Systems is the old fashion business we all should have the pleasure of dealing with for specialized equipment needs. I have both the 80 meter and 40 meter Comtek Hybrid couplers. They both have worked perfectly out of the box. Jim Miller at Comtek Systems has spent considerable time with me and others in helping us construct our 4-Sqr projects. 4-Sqr's are a home brewers project. You won't find one in a box. You have to construct the antenna's, supporting structures, radials systems etc.....so having the hybrid coupler allows you to focus on building the rest of your system. Many array projects get left on the drawing board due to the complexities of the feed systems. Comtek takes this step, put's it into a high quality product, which frees up time to concentrate on the array itself. Jim has always been very helpful over the phone, and enjoys his work. It shows in the craftsmanship of his products. My first season using his 80 meter hybrid coupler within my 1/4 wave 4-Sqr vertical array, I was able to work all 40 CQ zones and a 156 countries. I just got the 40 meter coupler and inserted it into a 1/2 wave dipole array and I'm looking forward to another rewarding season on the low bands- Jim provided me with both array designs in an instruction manual that is one of the best I've ever seen- 73 Paul N0AH Carpenter, Wyoming
 
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