But diffraction has little effect on the signal path. For UHF the path length need change by only ten inches to turn addition into subtraction. Metals reflect signals. A metal object 8 inches long is big enough to reflect UHF. Exceptions are aluminum siding, stucco (which has an embedded metal screen), and foil-backed insulation, all of which totally block all signals. F/B (Front to Back Ratio) - This ratio tells how good the antenna is at rejecting signals from the rear. There should be no horizontal or diagonal wires or pipes in front of the antenna. The front third of the antenna is a Yagi/Corner-reflector UHF antenna, and the remaining two-thirds is a Log-Periodic Dipole Array (straight or Vee type) antenna for VHF. But after 2009 VHF DTV stations will be more common. The effect is probably a few tenths of a decibel for UHF, insignificant for VHF. These objects should be further away than 2 feet for UHF, 4 feet for VHF-high, or 6 feet for VHF-low, and an even larger separation will help a little.

Connector types - There are many types of RF signal connectors (BNC, N, UHF, Reverse SMA, TNC, phono, etc). Limits of approach to energized equipment protect against arc flash exposure; specially designed flash-resistant clothing provides additional protection; grounding (earthing) clamps and chains are used on line conductors to provide a visible assurance that a conductor is de-energized. But if this 75-ohm antenna is connected directly to 75-ohm coaxial cable without a 1-to-1 balun, some signal picked up by the dipole will flow onto the outside of the shield conductor where it will be retransmitted and lost. Coaxial cable - used for radio frequency signals, for example in cable television distribution systems. CATV/MATV (Community Antenna TV, Municipal Antenna TV) - These are shared antenna systems for communities, apartment buildings, etcetera. Equatorial mounts are much simpler and much more common. If one element is removed, the drop in performance is usually much worse than the decline in the element total would suggest. It makes the element behave as if it is longer, maybe 10%-30% longer than it really is. To figure the loss in a longer cable, what are electric cables just add 1 dB for every 10 feet. Estimating the signal loss in ordinary construction materials requires knowledge of their water content.

Metal objects in the attic can block the signal. Insulators also prevent electrical shocks to other objects or people.The isolates are identified in the inscriptions that appear on it. If these reflecting objects are positioned to the side, to the rear, above, or below the antenna, they will have little effect on it, provided they are not too close. If there were a 25-inch diameter hole through the crown of the tree, and if the dish could be pointed at the satellite through that hole, then the tree would have no effect on reception (until the wind blew). If this is not true for the 300-ohm balun’s wires, the effect is equivalent to a small "point capacitance". Needle-Nose Pliers: Pliers with a long, tapered gripping nose of various size, with or without cutters, generally smaller and for finer work (including very small tools used in electronics wiring). Don’t buy the smaller crimp tools. Wires and metal pipes effectively reflect VHF, as do plastic pipes containing water.

Instead of being protected by NM cable sheathing, these wires are protected by tubular metal or plastic conduit. Telephone cables may contain four or eight wires, while ethernet cables (internet connection) consist of eight wires arranged in four twisted pairs. Faulty switchgear may cause an arc flash incident with a resultant blast. Like armored cables, metal-clad cables feature metal sheathing that offers protection to the wiring, allowing it to be installed in areas where it may be vulnerable to damage. UF cable is normally sold with gray outer sheathing. Gray sheathing is not used for NM cable but is reserved for underground (UF) cable or service entrance cable (SE or SER). Cables can be securely fastened and organized, such as by using trunking, cable trays, cable ties or cable lacing. Other ratios are possible by using two rods of differing diameters, or by adding a third rod. TV dish antennas are used for satellite reception both for C-band (requiring an 8-foot dish) and Ku-band. A freestanding half-wave dipole has a torroidal (doughnut-shaped) reception pattern, and has a terminal impedance of 75 ohms.