Glossary a To F > 커뮤니티 카카오소프트 홈페이지 방문을 환영합니다.

The secondary distribution wiring appears to be a duplex bundle in which the MGN serves as both neutral and mechanical supporting strand. The strand is placed under tension to prevent excessive sag; typical strand tension is a few hundred pounds, although a strand supporting a large multipair cable may be tensioned as high as 1000 pounds. Following are photos of a few representative examples. There are portable signal strength meters made for DTV, but they are rare and terribly expensive, and if they use a demodulation scheme different from what your receiver uses, their results might not apply to your receiver. There is no easy way to tell if a given TV antenna will work well for FM. Your first few cables will probably be unreliable, but eventually you will get good at it. The strand is placed under tension to prevent excessive sag; the typical strand tension is a few hundred pounds. The strand is placed under tension, and the communications cables are lashed to it.

Under this code, the highest cable in the communications space must be separated from the lowest electric-power conductor in the supply space by specified distances. IR); the output voltage of the circuit will be identical to that of the supply - and will drop quickly, but thanks to parasitic capacitances not instantaneously, when the load is connected again. Dropouts (weak signals) - On DTV channels you will never see snow, ghosts, or interference, but you will see dropouts. Telephone cables. - Traffic signals. Traffic signals - Pedestrian walk signals. A duplex bundle is normally used in situations where only a single 115-volt circuit is required; such circuits are typically provided for low-capacity loads such as streetlights and traffic signals. F/B (Front to Back Ratio) - This ratio tells how good the antenna is at rejecting signals from the rear. The F/B ratio is mostly a marketing gimmick, and is not a very useful number. This ratio is the gain factor in the forward direction divided by the gain factor from the rearward direction. But since gains and F/B ratios are usually given in dB, you normally get the F/B figure by subtracting the rearward gain from the forward gain (both in dB).

Most stepdown transformers are designed for single-phase operation; if a three-phase secondary circuit is required, three physical transformers are usually required, and may be mounted the same pole as shown in the photo above. Stepdown transformer: an oil-cooled transformer which converts the primary distribution voltage to the secondary distribution voltage. Transmission (sometimes called sub-transmission to distinguish it from transmission lines supported by steel structures): three uninsulated conductors which carry 3-phase high voltage (typically 69 to 200 kilovolts) circuits among substations. Primary Distribution: one to four uninsulated conductors, frequently supported on a crossarm, which carry power from substations to pole-mounted stepdown transformers. If such a splitter came between the power injector and the mast-mounted amplifier then the DC would go some place unintended. Interpreting the record - The FCC defines "Effective Radiated Power" (ERP) as the actual transmitted power multiplied by the transmitting antenna’s gain (relative to isotropic, not in dB) in its best direction. Antenna gains of 10 are common, so the electric bill is not what the ERP suggests. If these are not present, your image is perfect. The dipoles with the largest bandwidth are double-cone dipoles, but bowtie dipoles are somewhat effective at the same thing. Telephone and other communications cables are supported in the same manner.

The MGN is on the same crossarm as the primary conductors. For safety reasons, all exposed metallic surfaces must be bonded to each other and to the MGN. The Safety Zone Space is an unused space separating electric supply facilities from communications facilities. The safety zone space protects communications personnel from dangerous voltages (even if a technician "forgets" to wear a hardhat). On special order, three-phase service and/or higher voltages can be provided for specific customers. While many types of highly integrated digital circuits, such as microcontrollers, are extremely complex, their functionality is generally implemented using these basic devices - and can be easily analyzed as such. Among the more common are fire- and police-alarm wiring, traffic-signal control wiring, and closed-circuit audio or video communications circuits. Other: just about any other type of communications circuits. Secondary distribution conductors are usually twisted together in a bundle called duplex (two conductors), triplex (three conductors), or quadruplex (four conductors), although older secondary distribution circuits may consist of separate open wire conductors.

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