Low Profile 6 meter Cubical Quad

Local 6 meter AM  nets are becoming popular again.  Some nets are operating with restored vintage equipment such as Lafayette HA-460’s, Utica 650’s, Knight Kit TR-106’s, etc.   Some hams that would like to participate in the nets are faced with significant restrictions imposed on antennas by HOA’s.  In some cases, restrictions mandate that antennas cannot be taller than 10′.   The good news is that it is possible to construct a high gain horizontally polarized low profile 6 meter cubical quad antenna that provides good directional coverage for distances up to ~20 miles at a total height of 10′ above ground.

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Figure-1 is  a diagram of the antenna.

cubical-quad-diagram

Figure-1. Diagram of cubical quad antenna.

Figure-2 is a bar chart of the AutoEZ model predicted SWR for the antenna.  For modeling purposes  a 15.95 pF broadcast quality capacitor was placed across the feed point, a 4:1 current balun rated for 6 meter operation was connected to the feed point, and 75′ of Belden 9913-7F coax transmission line was specified.

6m-cubical-quad-article SWR

Figure-2. Model predicted SWR curve for the antenna.

Figure-3 is an AutoEZ model predicted elevation radiation pattern for the antenna.  The predicted elevation beam width is ~37° with a maximum gain of ~ 9.66 dBi @ 30°.

elevation-radiation-pattern

Figure-3.  AutoEZ model predicted  elevation radiation pattern for the antenna.

Figure-4 is the AutoEZ model predicted azimuth radiation pattern for the antenna.  At 50.4 MHz, the predicted azimuth beam width is ~75°.

azimuth-radiation-pattern

Figure-4.  AutoEZ model predicted azimuth pattern for the antenna.

I built a manually rotatable working prototype of the antenna to verify its “on the air” usefulness.  The antenna has a reach of about 30 miles.  I  use it for our local Vintage 6 meter AM net that meets on 50.4 MHz every Sunday night when I need more reach than my 6 meter interrupted loop at a height of 33′ provides.

Figure-5 is a photo of the manually rotatable low profile 6 meter cubical quad antenna that I built.

Figure-5. Prototype low profile 6 meter cubical quad antenna.

With a little work, the antenna can be constructed for rapid “put up/take down” operation.  Take a look at the fiber glass spreaders available from Max Gain Systems.  The antenna can also be fitted with a relatively inexpensive TV rotor to provide remote rotation capability.

If you like the characteristics of the antenna and would rather buy than build, take a look at the Rover 6 Quad from Dunestar.  The antenna is reasonably priced and is a rapid “put up/take down” antenna.  The Rover 6 can be quickly and easily erected using surplus military mast poles and a tripod mounting block.  Take a look at the tripod push-up mounting blocks available from GoVerticalUSA.com.  Figure-6  is a photo of a push-up tripod mount made by GoVerticalUSA.com.

govertical-pushup-tripod

Figure-6. Push-up tripod mount from GoVerticalUSA.com.

The EZNEC+ V6 and AutoEZ models (zipped format) for the antenna discussed in this article can be downloaded from the links below.

6 meter low profile cubical quad antenna models

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