An EASY DIY Gray-Hoverman Antenna

WARNING - This is a lengthy and somewhat technical explanation of how I’ve constructed and utilized this antenna. Probably too long for a blog, but note that I’ve tried not to leave anything out. You may want to check online and see what TV stations will be available over the air before beginning. Try TV Fool for DTV information on your location, and it can even create a map showing where to aim your antenna!

The Gray-Hoverman antenna was originally designed by Doyt R. Hoverman as a wide band UHF TV antenna in the 1960s. Yes, that was the old school TV with snow, ghosting and low resolution “I Love Lucy.” While it was designed long ago, it has enjoyed a resurgence in popularity and use due to its covering the frequencies still used by many HDTV channels. It’s also easy to construct and somewhat compact.

Q: Why would I want to watch over the air DTV when I have cable and cell service?

A: Over the air DTV can provide a cost effective way to lower your budget when combined with basic cable Internet access. Are you a Cord Cutter? It can also provide access to local programming and news at remote locations and in the event of an emergency. Lastly, it can provide access at relatively remote localities where Internet and cell service might not be available. Think conversion van, camper or a cabin at a semi-remote location.

Most people will find this antenna or its more elaborate versions far superior to the small “patch” antenna sold for $$ at the department stores. It can receive many more stations than its tiny store-bought cousins, and it’s a fun, easy and inexpensive project. You can use it indoors as well as mounting it in the attic, and you will be surprised at the number of stations you will receive even if you’re 50 or more miles from the TV transmitter. Add it to the pack items in your conversion van and watch some local TV at your destination!

While videos and websites detailing construction of this antenna abound, I’ve tried to simplify my plans so you obtain some quick results. You could use different lengths for the elements and add extra NAROD (Not A Reflector Or Director) elements to the top and bottom to boost specifically VHF channel gain. If you don’t have any local VHF channels such as 2,4,3,7,8 etc. that you want to receive, then building the NAROD on top and bottom just adds unnecessary complexity. I didn’t add the NARODs since channels 2, 4, and 7 in my NYC suburb weren’t work the extra effort yet.

Construction is relatively straight forward. Use thick, solid core copper wire since it will keep the antenna frequency response broad. I used 12 gauge solid copper wire from the home center, which is around 3mm in diameter. The solid core wire holds it’s shape better than stranded wire when constructing this antenna. You will see many people using wood as the substrate for this antenna, but I always recommend Plexiglass or its stronger version Lexan. Plastics in general have a lower relative permittivity or dielectric constant then other materials such as cardboard, particleboard or wood. That’s a fancy way of saying it won’t bleed off the precious signal strength of your antenna by electrically shorting the elements together. You want an electric insulator to be resistant to electricity. The RF signal should flow though the wire, and not what the wire is mounted on. This becomes more critical as frequency increases up into the VHF range and above to UHF. The piece of Plexiglass I used was a scrap left over from replacing broken glass in a window and it is 38 inches long by 5 inches wide.

The dimensions are not overly critical, but do try and keep as close to 7 inches per segment as possible. The ends of each wire segment can be shortened from the 7 inch length to 5 inches. Some builds suggest this helps in some way? Just fold over 2 inches at the end of each wire end and see if that makes any difference. This must shift the receive range slightly, but I didn’t see any difference in the amount of UHF channels I was able to receive.

Review the illustrations and you will see that I used the protective covering on the plexiglass to draw out a template to drill. I also made a cardboard template to aid laying out where to drill the screw holes. It’s shown in the illustrations and consists of two 7 inch squares held together by a thin strip. Make the side points of each square 10” apart and trace the layout onto the central plexiglass section as shown.


Here is a link to a construction video on my YouTube channel (coming soon)

Parts Needed:

  • 8/32 machine screws 3/4” long with washers and nuts to aid in bending and holding the wire as well as electrical connection

  • Lexan or plexiglass central section - Size isn’t critical as long as it can hold the screws at the required spacing. Mine is 38” x 5”

  • A 300 ohm to 75 ohm Balun transformer which matches the impedance of the antenna to the coax wire running to the TV

  • Around 15 feet of 12 gauge or thicker (Lower gauge numbers are thicker) solid conductor copper wire - Sold at most home centers by the foot or on various length spools

  • A length of 75ohm COAX cable to connect the antenna directly or through a matching transformer to the TV - Keep the coax as short as possible, since long lengths of coax cable attenuate or and cut down the signal strength

Construction and usage tips:

  • Start in the center of each side by carefully stripping 1/2 inch of insulation from the wire without cutting the copper center conductor itself. Next bend the stripped section around the center screw on each side, then work your way bending the wire towards the top and bottom.

  • Leave the four wire ends slightly longer than 7 inches until the construction is finished, and then trim them to length when done.

  • Mounting it higher from the ground will almost always give stronger signals, which equates to more channels you can receive.

  • Keep the coax cable as short as possible, which will minimize signal loss. Signal losses mean less channels received.

  • Remember that high VHF/UHF antenna that is clear from tree branches is ideal. Placing it near a window if used indoors will often work best. RF signals at these frequencies bounce around and can cancel themselves out in certain spots. (Yes, really!) Move the antenna around and see where it works best.

  • Best reception occurs off the flat front and back. Point either flat side toward the DTV station transmitter grouping, which is usually located in the nearest city. Adding the reflector makes the side away from the reflector most sensitive. It reflects signals back into the antenna after they pass through it! Adding a reflector will make some marginal channels receivable.

  • If you notice weak channels plagued by video that freezes or unreliable reception, try adding the reflector element behind the main antenna. Adding a Reflector Element gives appreciably more gain. I left it out for simplicity and since the channels I desired came in reliably without it.

  • DTV is digital. Either you receive the available channels reliably, or weakly causing freezing of the video. You might not detect a weak signal at all when your TV scans and tries to program them in from the Add Channels menu. A strong received signal just detects and displays the video. Having more signal gain into the antenna won’t make a well received signal look any better. That’s one advantage of digital TV!

  • Best results are usually obtained by using the 300 ohm (antenna impedance) to 75 ohm (coax wire lead in) impedance. You can try using this antenna without the balun if you don’t have one. Mine works without it but it seems like it’s more sensitive to where it’s placed in the room. Matching impedances is important for maximum signal transfer, but most always much more important for RF transmitters than receivers. Try it and with and without the transformer and see!

  • If there are “low” channels that you would like to receive in the VHF range, then add the NARODs. They electrically lengthen the antenna elements, which increases signal strength in the lower frequency signal region. I’ll explain the reflector and NAROD construction in a future post.

  • I’ve had mixed results with amplified DTV antennas, especially the small plastic box ones. An RF amplifier may cause strong signals to swamp the TVs input. A general rule seems to be to reduce signal loss from too long a length of coax lead in. Also try increasing signal strength with a reflector and moving the antenna to different and higher up off the ground locations. These work subjectively better than trying to amplify a signal that’s not making it into the antenna in the first place.

Have fun with this project, and please let me know how your antenna works!


Don’t buy it, build it!












Rocco Garzione

A tech instructor and builder of projects

https://myfundiy.com
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