UHF antenna for digital TV

November 30, 2016
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The Pennyloop UHF antenna offers high performance in a very simple and cost effective design. It is also a very compact design lending itself well to a variety of mounting options and locations inside and outside. Outside will give the best performance. The Pennyloop antenna started out as a single loop antenna and could be used with a reflector. It was found through extensive testing, at least in my area, that the UHF signal strength is very "layered". A single loop antenna, or even a simple thick element dipole for that matter, would pick up all of my distant stations - Just not at the same height! A new design emerged from this common issue with UHF signals. The antenna did not need to be excessively tall, but needed some additional height to cover each of the signal layers at the same time. This design goal was achieved in the Pennyloop by having a second loop installed on the original feed point. It served several purposes. It increased the gain substantially, focused more on the horizon where the signals were coming from, and gave the additional height needed to be in each of the signal layers simultaneously.

As with all antenna designs, there are compromises. Some antennas are omni-directional with little gain, and some are very directional with high gain. My antenna design, the Pennyloop, offers fairly high gain and is bi-directional without a reflector. It will work equally well, in both directions, which is great if you have antennas on each side of your location.The Pennyloop antenna was designed to be very easy to construct with basic tools and skill levels and the design is for coax feed - through an appropriate ground block - to the television set. This makes for a very easy and straightforward connection.

A few building and performance notes: Do not use any more coax than necessary to connect your antenna to the TV. Roughly speaking, you can expect about a .05dB loss per foot of coax [RG-6] at UHF frequencies. In a 50 ft. run of coax this equates to a loss of signal of about 2.5dB. A loss of 3dB is half of your signal! The prototype of the Pennyloop, pictured, has 51' of RG-6 that runs through a 3 GHz ground block to the TV and it is mounted at a height of 18' on my mast - easily receiving all of the stations that are located 55 miles away! I do not use an amplifier. Also, all connections, especially those going through splitters, will reduce your signal to the TV. If you have to feed a couple of TV's or have a very long run of coax, it may be necessary to have an amplifier/booster near the antenna. If a connection is necessary between lengths of coax, be sure to use a low loss splice barrel connector. These are available, like the ground block, for 3 GHz.

A search on can be nice to find information on station locations, power levels, etc. It will be necessary for you to aim the antenna towards the best, or desired, signals you wish to receive. The broadside or flat side should be pointing to the transmitting antenna and you should be able to look through the hole in the loop(s) towards the transmitting antenna direction. If you have multiple transmitters in one direction, or transmitters on both sides of your location, you can average it or you can point more in the direction of the lower powered stations. The antenna has a null off each edge, much like other loops, dipoles and yagi designs, but has a wide beamwidth (front and back - without a reflector installed) that makes it very nice for most installations. The mast mount described in this Instructable makes it very easy to mount and aim your Pennyloop Antenna.

Be aware that OTA (Over-the-air) television signals can be influenced by a number of things to include obstacles, terrain, weather, time of day and year, antenna height and aim, quality of build, etc. and you will have to figure out the best setup for your antenna system.

The #6 gauge bare copper wire is really great to work with. It is large enough to make an efficient element while still being easy to bend into shape by hand and with common pliers. #4 gauge copper wire could also be used, but will require more effort to attain the proper loop shape. Bending the ends of the wires, for attachment to the feed points, is where it gets tough if you choose the heavier wire. Many different materials and possibilities are available for this build and what I have presented in the plans is what has worked best in the interest of simplicity and ease of construction. Be creative and experiment if you choose to do so. It is great fun to play around with element thickness and lengths, connections, etc. in the pursuit of better signal strength and quality.

*Many other websites have detailed information about mounting, aiming, grounding requirements, NEC requirements, etc.

The Pennyloop antenna requires very little hardware and offers great performance. Here is a list of what is needed for the build. (The list includes everything to build the Pennyloop as shown in the photos. You may choose to mount it in different ways and all the listed items might not be necessary. It is mounted about 3/4 of a wavelength from the mast. This distance is not critical and I have mounted horizontally polarized loops very close to my metal mast. Test the antenna in a few temporary setups to see what works best for you.)

1. Coax - RG6

2. Two feet of 3/4" PVC Schedule 40 (Either the white plumbing type or grey conduit type) along with 2 slip caps and a 90 degree elbow [ Some big box stores sell a short 2' length of PVC if you don't want to handle the 10' length]

3. #6 gauge bare copper wire (2 lengths of 28"-28 1/2")

4. #6 x 32 x 1" stainless screws and nuts (2 screws and 4 nuts)

Source: www.instructables.com
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