Now that the decision has been made to install the off-air antenna inside your attic, now the fun begins!
Where is the Signal?
This is probably the easiest part because of a free service called AntennaWeb, sponsered by the CEA (Consumer Electronics Association).
Good TV antenna selection is not based on distance from the transmitting station except in rural environments. Good reception is based on accurately characterizing signal conditions, and selecting an antenna that works in that situation.
That is why this antenna selection guide has been prepared by applying massive computing power to massive databases to compute antenna requirements in every neighborhood. Even with this amazing capability, assuring good TV reception requires attention to details in your neighborhood and proper installation.
Selecting An Antenna
1. Go to the antenna selector page of www.antennaweb.org and fill in your address and other relevant information.
Check the button that says "Show Digital Stations Only" and this will bring up a list like the one below, assuming you live in close enough proximity to any transmitters.
The CEA site provides this excellent information, but there is one issue that people have with it. For one city, it will often recommend a variety of antennas one should get to receive HDTV signals. Obviously, most people do not want to outfit their home with numerous antennas, so some trade offs are typically made.
From this chart you can determine the type (UHF or VHF), power, and style antenna that should work best for your needs.
2. Check to see if all of the digital channels in your area broadcast on the UHF band.
Look under the columns titled "Antenna Type" and "Frequency Assignment" or refer to a list of digital stations broadcast on the VHF band. If you need to receive low frequency VHF stations (Channels 2-8) you may need a VHF antenna.
3. Determine how far will your antenna be from the transmitters?
Look at the "Miles From" column on the far right side of the chart and then choose from the following:
- Indoor: 0-15 Miles
- Short Range: 0-25 Miles
- Medium Range: 10-55 Miles
- Long Range: 50-70+ Miles
4. Determine whether you need a uni-directional or multi-directional antenna?
In some cities like New York, Chicago, and Los Angeles, all stations are broadcast from one central area, the Empire State and GE Buildings in New York, the Sears Tower or Hancock Building in downtown Chicago, and Mt. Wilson in Los Angeles. In other cities like St. Louis, the transmitters are scattered around the city.
 Check the "Compass Orientation" and if all of your desired stations are transmitting from the same area or within 20° of each other you can use a uni-directional antenna. If the transmitters are positioned more than 20° apart, it is best to use a multi-directional antenna. It is important to note that most multi-directional antennas will work in place of uni-directional antennas, but you may pick up some multi-path distortion.
By clicking on the "View Street Level Map", you can get a graphical representation of your compass orientation.
While you have the legal right to erect an antenna on property you either own or control, many people will still install antennas in attics for aesthetic reasons. Your rights regarding antenna installations on your property are explained in more detail on the FCC's web site.
In general you can lose up to 40-50% of your signal's strength from an attic installation due to the loss from roofing materials, but with proper installation and the right antenna you can overcome some of this loss and be successful.
Mounting the Mast
1-¼" conduit makes a great antenna mast. The material can be metal or PVC. Conduit scraps from a local hardware store can be used to secure the mast to trusses or joists using standard deck screws. This will give you some flexibility should you need to relocate the antenna. Avoid using wire or twine to hang the antenna, as this will make positioning of the antenna more difficult. If you can't find 1 ¼" pipe, don't worry, all of the antennas we sell, have mast clamps that adjust from 1" to 2" in diameter. We also sell a 30 inch tall "J" Mount Mast that can be attached to any solid surface. This offers a very flexible and compact mounting option for tight spaces.
Before purchasing the antenna, make sure you have enough space to be able to rotate it for the strongest signal.
Keep It Away From Metal
It will be important to keep the antenna away from metallic surfaces. Air handlers, ductwork, electrical conduit and data wiring can all present interference with the digital signals. Try to keep as much distance as practical from these objects (6 feet or greater distance is ideal). If you have foil backed or "solar shield" insulation in the roof joists, then you will need to replace the insulation in the area surrounding the antenna or place the antenna outside. The digital signals will not pass through metal surfaces.
If you have a metal roof, installing your new antenna in the attic will be very difficult and have a low probability for success.
Overcoming Loss from Roofing Materials
Since signals will be weakened by just about any roofing material, utilizing a higher gain antenna is typically the first step in overcoming signal loss. The effective range of most antennas is lowered by 10-15 miles with an attic installation, so you may consider getting a more powerful antenna than you would typically need with an outdoor antenna.
Investing in a low noise pre-amplifier can also improve the signal levels. Antenna mounted pre-amplifiers are always preferred as they amplify the signal at its strongest point. It is also important to use amplifiers designed for high ambient temperatures. Checkout our selection of antenna pre-amplifiers.
Wiring the Antenna
Most antennas are equipped with female "F" type coaxial connectors that integrate with standard RG6 coaxial antenna cable. If your cable run is greater than 50 ft., an antenna pre- amplifier is suggested to ensure the signal quality is not lost between the antenna and tuner (Television, Satellite Box, HDTV Tuner, etc.). A signal amp won't help you pull in distant stations, but will help you over come signal loss from long cable runs, splitters and junctions. PL Depot offers a wide selection of RG6 Coaxial Cable, Installation Tools, and Installation Accessories to meet your installation wiring needs.
Troubleshooting
When servicing an existing system, be sure to check
the strength and quality of the signals being received
and the condition of the equipment being used.
Measure signal levels with a field-strength meter.
Check general picture quality with a TV set you know is operating correctly. You may find that an improper installation or a change in reception conditions is causing problems that can easily be solved. Defective components within the customer’s TV set can also cause problems. To determine whether the cause of a reception problem is the customer’s TV or the antenna system, connect your test TV to the antenna system. Compare the picture on the customer’s set with the picture on your test TV. If your test set produces an acceptable picture, the customer’s TV set probably is the source of the problem, not the antenna system. Unless you are a qualified electronic technician, do not attempt to fix the customer’s TV set. Instead, advise the set owner to call a qualified TV technician.
For non-digital signals, certain picture characteristics may indicate the source of the problem. Ghosting, channel interference, CB or Ham Radio Interference, FM Interference, and pre-amplifier overload may all affect picture quality on non-digital signals. With digital signals, if the signal is not sufficient your simply will not obtain a picture. Check the Comprehensive Antenna Installation Guide published by Channel Master for more details on identifying these problems. |