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OTA Antenna Installation Guide for HDTV Reception: Placement, Preamps, Cabling, and Grounding

Dale Cripps · 2001–2004

Summary

This practical guide walks HDTV viewers through selecting, installing, and grounding an outdoor OTA antenna using AntennaWeb.org to identify local DTV channels and determine signal requirements. It covers preamp placement, RG6 cabling, rotor considerations, attic versus outdoor mounting tradeoffs, and proper grounding rod installation to protect against lightning damage.

THE ANTENNA

An antenna is excited by radio waves which produces a certain level of signal. They come in all kinds of sizes and shapes. The most common are VHF/FM/UHF combos and UHF only. HDTV reception can be either UHF or VHF. How much signal you will need depends on your distance, elevation and buildings within 4 blocks. The key is to get the signal level just right. Too little or too much can cause problems.

Go to http://www.antennaweb.org/aw/welcome.asp and click on "choose an antenna". Inserting your address is recommended or use zip code and answer the two remaining questions. Click submit. You now have a listing of all stations you have a chance of receiving and print it. At the top of the listing click on "map station distribution" and print it also. The stations on the bottom are the furthest away and you may not even recognize them. From the bottom work your way up to your local analog stations and click on one of them in the same color group. Do not misunderstand this step and click on the DTV channels. You will need to use your NTSC stations as your antenna selector guide for now since they are not transmitting DTV at full power yet. Now you have information that tells you what antenna you need, if a preamp is required, where the transmitters are and the "real" DTV channel numbers. The antenna is cheap. Major expenses will be all the other stuff and your labor. If all the transmitters are basically from one direction you probably will not need a rotor. If not make a rotor part of the budget because most installations need it to avoid problems or to get that tough to receive channel. Use RG6 cable and the proper connectors. It is assumed you know how to properly terminate the cable.

The FCC has legally allowed you to mount an outside RF antenna of any size up to 12 feet above the roof line regardless of your home owners association rules and regulations. I am not providing legal counsel but based on some people who lost such a case and take the antenna down I suggest you use this option as a last resort. For more information contact the FCC or check this link http://www.fcc.gov/mb/facts/otard.html

Buying the antenna and associated stuff was the easy part. Installing it is work. In the installation make allowances for the possible rotor and wiring ‑ you will appreciate this step later if you need one. Once you get the system installed changing the antenna itself is easy and cheap so don't sweat what kind of antenna you bought too much. Many people have had success mounting the antenna in the attic. The performance you will get varies but bear in mind that the materials used for your roof could kill your signal. Humidity can also have a big effect on the reception when using the attic. Bottom line is installing it outside is always preferable over the attic. If you have a multi level dwelling and live in a subdivision that does not allow roof top antennas you may be able to mount it under a rear deck which is still better than the attic ( worked great for me ‑ might not for you )or in the backyard. Place the antenna for the least obstruction of anything between it and the direction it will face ( if possible ) and point it towards that direction using the "map" you printed out. Pay attention to boots, covers and seals which keep out the elements. Preamps come in 2 sections and I recommend it have variable gain rather than fixed. One part is the actual preamp and it belongs on the antenna mast as close to the antenna as reasonably possible, NOT in the house. Allow SLACK for turning the antenna by hand or with a rotor. The other part is the power supply and that is what goes in the house. Make sure it is accessible and within VIEW of the TV so you can tweak the gain. It must have live AC at all times so DO NOT use a switched outlet. Terminate the cable PROPERLY with the CORRECT connectors with the proper CRIMPING tools or you will detune the system. NO, you can't just use pliers and "squish" it or "pinch" it on.

Another issue is grounding to protect you and your property from lightning damage. If you installed the antenna in the attic then skip this paragraph since grounding is not required. For outside antennas grounding the mast and running the antenna cable through a grounding block is required by code. You will need an 8 foot copper grounding rod, grounding block, RG6 coax ground wire attached and 2 ..... To install this grounding system you simply run your coax to the antenna or preamp. Strip the ground wire off the coax to about a foot above the base where you will have installed the ___- and attach the ground wire to it. Determine your cable run and where a good place will be for the grounding rod and block. Now comes the really hard part which is to drive that 8 foot rod into the ground about 6-7 feet. Attach the _____ to the grounding rod. Install the grounding block on the house or some other support near the rod. Take the extra grounding wire and connect the grounding block to the ______ on the rod. On the cable determine where you are going to cut and terminate for the grounding block and cut just the coax not the ground wire. From that point determine how much grounding wire you will need to from the termination to the rod and strip that off the other side of the cable and cut the ground wire from it. Now terminate and install the coax to the input of the grounding block and the grounding wire to the ____ on the grounding rod. You are now fully grounded. Take the other end of the cable and terminate and install on the output of the grounding block and complete the run to the TV or preamp power supply.