Introduction: Gray Hoverman TV Antenna Active Element Jig

Picture of Gray Hoverman TV Antenna Active Element Jig

This jig makes it easy to form the zigzag active elements needed for every version of the Gray-Hoverman tv antenna, using prepared links of common quarter-inch diameter copper tubing. The time and effort needed to make the jig will pay off in the quality and consistency of the elements produced, and the jig can be used many times if friends or neighbors also want to build their own antennas. My method produces elements that are durable, lightweight, have the desirable sharp corners and have holes for mounting the elements to the antenna's framework. This is one of three Instructables about making the active elements. To see the other two and my related Instructables, click on unclesam in the INFO box to the right, then repeatedly click NEXT to page through them all. To receive automatic notice when I post future Instuctables about my method for assembling the entire outdoor antenna, members can click to subscribe  to me.

Step 1: Materials and Tools

Picture of Materials and Tools

Materials
Base: particle board or plywood, flat, 12 inches by 32 inches, one half to three quarters of an inch thick; edges do not need to be perfectly straight or smooth, nor the corners perfectly square.
Screw Posts: nine 6-32 screws, one and one-half inches long; twenty-seven 6-32 nuts; eighteen number six flat washers.
Tools
Drawing paper 12 inches by 32 inches (Optional) You can also draw directly on the base board, but paper will allow greater precision.
Drawing compass(es), having hard, very sharp pencil lead or dividers having very sharp points; capable of drawing arcs up to 7.07 inches (180 mm) radius, such as Dasco Pro, Inc., Giant Circle 12-inch Beam Compass shown in photo.
Pencil having hard, very fine point
Straight edge, such as yardstick, metal version preferred
Framing square
Ruler, one foot long, divided into tenths of an inch or in millimeters
Drill press
Drill bit nine sixty-fourths (0.140) inches diameter; another bit about half that diameter for pilot holes
Center punch
Screwdriver, for 6-32 screw head
Wrenches, two, for 6-32 nut
Medium-width permanent marker

Step 2: Layout

Picture of Layout

Care in the drawing is essential to making quality antenna elements and in facilitating their construction. It is more important that each of the arcs intended to have the same radius do have the same radius, than that the radii are perfectly the radius specified. DO NOT DRAW DOTS AT THE LINE INTERSECTIONS. The intersections need to be located with as much precision as possible, and the drilling of the holes needs to be done with great care.
The design of the Gray-Hoverman antenna and its dimensions are protected under license (by others). This information is offered free for personal use, but no commercial exploitation is permitted. This is a link to the color pdf drawing of the antenna that I used for the active element dimensions http://www.user.dccnet.com/jonleblanc/Canada_TV_Stations/Gray-Hoverman/DBGH_VHF_hi_Antenna.pdf. In the final step I provide links within the digitalhome.ca website that provide history, description, performance, variations, and construction examples of the antenna, as well as to the license.

Step 3: Draw Six Five-Inch (127 Mm) Arcs

Picture of Draw Six Five-Inch (127 Mm) Arcs

1. Draw a straight horizontal line no farther than one inch from the lower edge of the board or paper, it need not be perfectly parallel with the edge of the board or paper.
2. Draw a straight vertical line perfectly perpendicular to the base line and no farther than one inch from the left edge of the board or paper.
3. Adjust the compass to 5.00 inches (127 mm) and, working from the left intersection, mark off six equal spaces along the base line, as shown in the photo. Do not draw dots.
4. Draw a straight vertical line perfectly perpendicular with the base line, at the intersection of the sixth arc.
5. Check the perpendicularity of the two vertical lines by confirming that they are 30.00 inches apart at their top ends.

Step 4: Draw Six 7.07-Inch (180 Mm) Arcs

Picture of Draw Six 7.07-Inch (180 Mm) Arcs

Adjust the compass to 7.07 inches (180 mm) and make arcs from only those intersections on the baseline indicated in the photo. Do not draw dots at the intersections.

Step 5: Draw Two 5.41-Inch (137 Mm) Arcs

Picture of Draw Two 5.41-Inch (137 Mm) Arcs

1. Adjust the compass to 5.41 inches (137 mm), set its point at the intersections of the two vertical lines and two of the 7.07-inch arcs, and draw an arc near the end of each vertical line. The photo defines the nine points at which holes will be drilled for the screw posts, but do not draw dots. Note that the distance between the screw posts will be identical to the dimensions provided on the antenna drawing, except for the screw posts at the bitter ends of the two short stubs. The copper element stub links will be the same length as specified on the antenna drawing, but the screw posts for the stubs are intentionally 0.18 inch closer together.
2. If drawing on paper, tape the paper to the base board and transfer the nine points to the board by poking through with a very fine sharp pin. It is OK to draw a light open circle, at least a quarter inch in diameter, around each of the pin points in the board to make it easier to locate them when drilling.

Step 6: Punch and Drill

Picture of Punch and Drill

1. Carefully make an extremely small center punch mark at each of the 9 points on the board.
2. Drill a pilot hole through the board at one point, using a bit about half the diameter of the nine sixty-fourths (0.140) inch diameter bit, as an aid to centering the drill press in each punch mark.
3. Without moving the board, switch to the nine sixty-fourths (0.140) inch diameter bit and carefully drill through that pilot hole.
4. Repeat to drill the remaining eight holes.

Step 7: Screw It

Picture of Screw It

1. Draw ink lines linking the holes to make it easier to visualize assembly of the antenna elements.
2. Insert a screw in each hole, with a washer on each side of the board, and snug on a nut at the base of each screw post.
3. Add two more nuts to each screw post, adjust the upper nut so its top edge is one quarter of an inch from the top of its post.
4. Hold the upper nut and tighten the lower nut against it to jam it in place, ensure the quarter inch spacing. These two nuts will never need to be removed.

Step 8: Label the Links

Picture of Label the Links

Mark letters beside each link as shown. Add a small U or L near the ends of each link, as a reminder which link will be the upper and which will be the lower at each screw post during final assembly. It is easiest to place the links onto the jig by first placing all the lower links, then adding the upper links, reverse the order when removing them.

Step 9: G-H Antenna Information Links

Picture of G-H Antenna Information Links

1. Introduction to the Gray-Hoverman antenna
http://www.digitalhome.ca/ota/superantenna
2. Antenna Research and Development Forum
http://www.digitalhome.ca/forum/forumdisplay.php?f=186"
3. Photo of mast-mounted outdoor G-H antenna (by others, post #94)
http://www.digitalhome.ca/forum/showthread.php?t=99907&page=7
4. License governing the use of the antenna design information
http://www.gnu.org/licenses/gpl.txt

Comments

PenJet (author)2013-06-07

Extremely innovative! Love the use of the copper tubing. Seems really well thought out and with an eye toward quality construction.
2 QUESTIONS:

1) have there been any simulations done on this methodology (nec).as far as gain, etc. and are the data available?

2) using the nikiml models (to make a GH2n2 or n3), do I make the tubing lengths to the same size as specified by nikiml for the #6 wire, or are their any modifications to make for the tubing element?

unclesam (author)PenJet2013-06-08

PenJet, when I built my most recent antenna, which I call GH10n3 SNAP, I developed a way to make the active elements from copper tubing without the need to build a jig. I used the antenna's plastic tubing frame as the assembly jig. The same method shouId work with any model GH. I have not created an Instructable about how to do it, but I included a long photo caption describing the procedure in a photo album at digitalhome.ca. The link to that album is http://www.digitalhome.ca/forum/album.php?albumid=1050. Click the photo to see the caption.
unclesam

unclesam (author)PenJet2013-06-08

PenJet, do note that I have posted several other Instructables about the construction of GH antenna active elements using prepared links of copper tubing. Your Q: 1) nikiml has been asked many times whether using copper tubing instead of solid #6 copper wire or instead of 1/4-inch outside dia aluminum rod or tubing (specified for his more recent antenna designs), makes any difference, including again just recently. His answer: the difference is negligible.
2) Before I pursued the use of links of copper tubing with their ends flattened, I asked at the digitalhome.ca forum whether flattening the ends would make any difference, was told it would not, that no compensation in dimensions was needed. There is a difference in the lengths of the tubing lengths versus the specified lengths for #6 wire. However, note that the lengths in both cases are to be measured at the CENTERLINES of each. Therefore, the lengths specified by nikiml for a #6 wire length would fall at the centerlines of the holes drilled at the ends of my tubing lengths. You need to cut the tubing lengths longer than that in order to create the flat pads that are drilled and are soldered together. My other Instructables about building the active elements show the details. To find them, click on my username or enter unclesam into the search box on the Instructables home page. Scroll to find all applicable projects.
Hope this answers your questions, unclesam

crc60 (author)2012-12-12

Thanks for the excellent tutorial.

You can and should delete all references to the GNU GPL as the Gray-Hoverman antenna "designs" are in the public domain. Copyrights and, thus, the GPL, do not apply to designs.

You can, of course, apply the GPL to your photographs and text description if you like.

smessud (author)2010-11-13

Thanks for the ible but could you make the legal story clearer?

Step 2 says "The design (...) and its dimensions are protected under license (by others). This information is offered free for personal use, but no commercial exploitation is permitted.", and step 9 shows us a GNU license.

I believed the GNU license let you free to copy, but you had to distribute under GNU, that is you also could be copied.

What exactly is copyright, is it design, dimensions or the clever tubing element?

Have a nice day.

unclesam (author)smessud2010-11-14

smessud, the design of the Gray-Hoverman antenna, including its specific dimensions, is covered by GNU (by others). Further information about that may be found at the links I provide in the final step at digitalhome.ca and to the GNU. I have nothing to do with the design of the antenna.
My innovation is the construction of the antenna's active elements using links of copper tubing by the methods I include in my three Instructables. The dimensions are copyrighted, my method is not. The three Instructables are covered by the Instructables license, as seen on the INFO box to the right. More about that can be found at this website.
Bottom line, if you want to build yourself a Gray-Hoverman antenna, you are allowed to, and if you want to use my method to make the active elements, you may. That is my sole purpose for providing this information. If you have some other use in mind, you should address your questions to either Digitalhome.ca or Instructables.com, whichever applies. My interest is not in the legal issues, it is in sharing how to build things with other like-minded people.
Unclesam

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