Is there a question you have? send us an email and we shall try to respond .......
How do you feed a multi-band quad ... ?
Feeding any multi-band array often is a challenge. The frequency range varies from 14 MHz to 28 MHz and the source impedance for each band may vary 2:1 in value. A quad is an array of three or more separate antennas, each with an independent feed point and elements occupying electrically different locations in the array. Methods of feeding in the past have been to co-locate all the feed points and using a single coax feed. With an antenna tuner in the line this method can give good results. Since the feed point impedance on 20 and 17m may be close to 50 ohms, and 10 and 12m over 100 ohms with 15m somewhere in between, some form of impedance matching is required.
The "gamma" match is one method that is effective and used by some quad suppliers in the past. Great for getting the "perfect" match, but often a "bear" to tune as there is a lot of interaction from band to band. Another problem has also plagued the gamma match and that is a reliable, weather resistant capacitor. Finally the gamma match adds more components, weight and mechanical problems to the assembly. The gamma match is not one of our choices.
Our preferred method of feeding a multi-quad is with separate coax feeds and selecting them with a remote antenna switch. Using 1/4wave (or odd 1/4w) 75 ohm cables as a linear two to one impedance transformer for 10, 12 and 15m (40m also) and 50 ohm cable for 20m and 17m bands. Information on making these quarter-wave feed lines is detail in our instructions (Prepared cables are also available from Cubex).
Another single coax feed solution is the Cubex Matching Transformer. This device has a single 50 ohm feed, and three levels of balanced output, and is positioned at the center of the driven elements (at the 15m band feed point). There are transformer terminals for 10m, 15m and 20m with 12m co-connecting to the 10m terminals and 17m shares the 20m termination. Although this is a cost effective solution, there are some compromises. Because this transformer does not have perfect isolation between bands, some of the characteristics of the antenna are effected. Bandwidth for 2:1 SWR is reduced about 25% from the direct feed result, and the normally very deep side nulls may be reduced.
How does a quad hold up in my part of the country ?
One of the more frequently heard comments or question is regarding the quads is its reliability in severe environments. Many acknowledge the quads superior performance, but think that they won't survive the conditions in their area. We have example after example of the ruggedness and reliability in severe wind (Hurricane force), winter snow and icing. I refer you to the "Customer Comments Page" on this website.
Do you have customer referrals near me ?
In general it is not possible to track all of our users and verify their willingness to be contacted. But many do send us comments and photo's of their installations. Take a look at our "Customer Comments Pages", and the "Customer Photo's Page" on our website.
In addition there are comments regarding Cubex antennas on the "eham" website - http://www.eham.net/reviews/detail/325 and http://www.eham.net/reviews/detail/423
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Do you make.... ?
We often are asked about the availability of special models - Single band arrays, WARC bands only, and other band combinations.
The answer is we have done all of those things. If you have a special need, it is best to summarize your requirements and send them via email to Cubex@cubex.com . Remember that some combinations, such as a Mono-band 20m, won't result in any significant cost savings because there is very little material reduction. The most expensive parts in our HF series of antennas are the fiberglass spreaders and cast aluminum hubs. The reduction then is only the other bands element wire and a little less effort on our part. Check the EXPO HF line-up of HF Mono Band and Dual Band antennas for lower cost alternatives to the MARK Series.
We have made antennas for the Marine Bands, FAA aircraft frequencies, Specials for FM broadcast band, 4 meter amateur band (72mHz) and other special frequencies or configurations. Our line of antennas cover the frequency range from 7 mHz to 470 mHz in various discrete ranges. If you have a special request please detail your requirements and send them to us via email.
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Will the quad work on vertical polarity ?
The polarity is a function of where the driven element is fed. All of our quad designs may be either Horizontal or Vertically polarized which is determined at the time of assembly.
Can I switch the Polarity?
Methods of remotely switch polarity have been designed and may be offered on some other brands of quad antenna products. At Cubex we have not found reliable and cost effective methods to allow us to offer that feature. Mechanically rotating the boom in its mounting does accomplish the task, but does require physically rotating the feed point 90deg.
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What is the difference between the MARK Series and SKYMASTER KIT Series Quad antennas ... ?
The Electrical performance is the same when the Skymaster is fabricated according to the instructions supplied. The primary difference is the SKYMASTER Series is a KIT of parts and material that require measurement, cutting of fiberglass, drilling of holes and assembly.
The MARK Series has pre-cut elements, pre-formed element wires, and one piece, pre-drilled, tapered fiberglass spreader arms. Some of the materials are different, e.g. the SKYMASTER spreaders are made up of three sizes of telescoping fiberglass tubing. They are strong (1/8" wall thickness) but a little heavier then the tapered arms of the MARK series. Basically it is your labor and skills versus ours. The SKYMASTER is an excellent value and a source of materials for those who wish to design their own quad antennas.
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What is the cost and how do you ship your quads...?
Most of our antennas are shipped via UPS or FedEx the Continental USA. The larger HF antennas with the longer lengths of booms via truck freight.
Overseas shipments ,depending on size and weight, ship via DB Schenker to the customers nearest major airport. We can quote shipping costs, but import duties, and taxes are not included and must be determined locally.
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