Outdoor antennas must be grounded for best reception and protection (no guarantees) against lightning strikes. Indoor and attic antennas do not need to be grounded. However, when an indoor antenna cable is longer than 30 feet, grounding the system will help reduce static electricity build up which reduces reception.
ANTENNA RESTRICTIONS PROHIBITED
Federal law prohibits restrictions (by governments, community and homeowners' associations, and other entities) that impair the installation, maintenance or use of antennas used to receive video programming. Masts higher than 12 feet above the roofline may be subject to local restrictions. The FCC's webpage OTA Reception Devices Rule has more details, also see the Electronic Code of Federal Regulations webpage Title 47, Subchapter A, Part 1, Subpart S.
The antenna should be mounted as high as possible and have a clear line-of-sight (no hills, structures, trees, etc.) to the broadcast towers. The higher the antenna is above the ground, the greater the signal density. The higher the antenna is above ground clutter, the lower the signal loss. Avoid installing near overhead power lines, the electromagnetic fields can cause interference or signal reduction, and the lines are dangerous to work around.
Side structure mast mounting (with 2 point or 2 bracket mounting) is the preferred method. Roof mounts must be installed more carefully to prevent water leaks. Mast are typically 18-gauge galvanized steel tubes with a 1.25 inch outer diameter. Most mast come in 5 or 6 foot sections, many are designed to connect for extended length. Limit extensions to two sections.
ANTENNA POINTING ANGLE
Antenna direction is commonly measured in degrees off of True North, several degrees different from Magnetic North for most locations. Magnetic north varies with location, and slowly changes over time. When using a compass to point an antenna, account for the difference between True and Magnetic north. The National Oceanic and Atmospheric Administration (NOAA) website has detailed information and a calculator for Magnetic Declination. Note that local conditions could effect a magnetic compass reading. If possible use landmarks to confirm or establish true north.
An outside antenna should be grounded with AWG 10, commonly called #10, copper wire and a coax ground block -- a coax cable barrel connector with a ground wire attachment. The ground wire can be insulated or bare, installed outside and inside, and should run as straight as practical.
A coax cable runs from the antenna to the ground block, and a ground wire runs from the mast to the coax ground block. The coax then runs to inside the home, the ground wire goes to an earth ground inside or outside. The ground block should be close to the conduit the coax cable enters the home, and can be mounted inside or outside depending on where the earth ground is picked up.
The earth ground can be a ground rod (Figure 1), or the electrical service electrode ground system (Figure 2). The National Electrical Code (NEC Section 810) connects to the service ground. The service ground can be accessed by clamping the ground wire to the metal pipe running straight into the ground from the power meter or fuze / breaker panel. The ground wire can also be connected to the fuze / breaker panel ground bar instead of the pipe.
Figure 1 - Common Installation|
Figure 2 - NEC compliant Installation|
The coax Drip Loop allows rain to collect and fall (drip) off the bottom of the loop instead of collecting at the conduit into the home. Additionally, all outside coax connections (antenna, ground block, connectors) should be protected (covered) with a rubber weather boot or electrical tape. Many antennas come with a weather boot for the cable to antenna connection.
Some installations use an additional (optional but not requried) ground rod close to the ground block, when the block is not close to the service ground. The NEC calls for a ground rod depth of 8 feet. A cold water metal pipe running into the ground makes a good ground (rod). Make sure the underground pipe is not plastic (PVC). The NEC specifies the ground connection be within 5 feet of the point the pipe enters the ground. The ground rod and service ground should then be connected with AWG 6 copper wire.
An antenna mast or cable within 5 feet of a swimming
AWG - American Wire Gauge
TOOLS AND PARTS LIST
Basic tools needed include a ladder and assorted screwdrivers, wrenches, sockets, and maybe a hammer etc. You will also need a wood and/or concrete drill, and appropriate drill bits and screws, for mast mounting.
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A multiple antenna system requires a signal combiner / splitter to enable signals from all antennas to go down one cable. A signal splitter is (also) a signal combiner. Combining signals has the same loss as splitting signals, signal loss is the same for both directions. Also see Signal Splitters / Combiners loss.
TV Antenna Installation
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