Passive Repeater


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Repeater, Passive

 

a device in the form of a mechanical structure of a definite shape, an artificially produced, electrically conductive medium, or a celestial body that is capable of dispersing or directionally reflecting the energy of radio waves; such repeaters are used as intermediate points in radio communications links. In radio-relay communications links, plane reflectors and antenna systems with reflector antennas serve as passive repeaters. In space communications, passive communications satellites may be used, such as the American Echo 2, a balloon 40 m in diameter, made of polymer film with a reflective aluminum coating; other means used include belts of needles, artificially produced clouds of metallic vapors ionized by radiation from the sun or by radio radiation from the earth, and the surface of the moon.

In contrast to an active repeater, a passive repeater can serve a communications network containing virtually an unlimited number of communications links operating at various, even closely adjacent, radio frequencies. Such operation is possible because a passive repeater reflects or disperses the energy of many simultaneously arriving signals without any mutual interference. With passive repeaters, the required energy level of the redirected signal is provided by increasing the power of the transmitter, increasing the dimensions of the antennas in transmitting and receiving stations, by narrowing the passband of the communications channel, and by reducing the speed of information transmission.

REFERENCE

Chistiakov N.I. Osnovy radiosviazi i radioreleinye linii. Moscow, 1964.
References in periodicals archive ?
PSC to Wake County Courthouse passive repeater to Raleigh-Wake Emergency Communications Center (RWECC) (Replace Existing) D.
Staff from both companies made several tower and rooftop climbs in the Manchester drizzle and rain and determined they could get line of sight if permission could be obtained to mount a passive repeater on an 11-story office building 90 degrees off the direct path between offices.
A passive repeater simply redirects the unamplified signal.
The longer path capability of microwave, especially important when using a passive repeater, can offer a higher-strength "receive" signal than infrared, whose distance limit is much shorter.
Problems occur with only a very small percentage of passive repeater applications due to the particulatr environment of the installation.
Will the passive repeater appearances be acceptable in the planned location?
When a passive repeater is oriented toward the southeast, the panel assembly may be frosted in near-sub-zero temperatures very early in the morning.
The chart illustrates the range of passive repeater orientation that causes the greatest susceptibility to temperature-differential problems.
Turning to covers to reduce the effects of icing, Microflect, for example, has developed de-icing kits for all of its passive repeater models.
If only half the passive repeater is clear of ice, the received signal level will be down by 6 dB, which is usually tolerable under the usual stable path conditions on winter.
Back-dish passive repeaters were used in several locations to get around obstacles.
As opposed to passive repeaters which simply amplify the signal, the XCel-4e fully terminates and regenerates the signal, allowing it to be repeated multiple times.