In electromagnetic transmission devices, especially those dealing with telecommunications, effective radiated power or equivalent radiated power (ERP) is a standardized theoretical measurement of radio frequency (RF) energy using the SI unit watts, and is determined by subtracting system losses and adding system gains. ERP takes into consideration transmitter power output (TPO), transmission line attenuation (electrical resistance and RF radiation), RF connector insertion losses, and antenna directivity, but not height above average terrain (HAAT). ERP is typically applied to antenna systems.
For a simplified example, if an antenna system has 9 dBd gain and 6 dB loss, its ERP is 3 dB more than (equal to double) the TPO. The use of circular polarization, or otherwise splitting equally between horizontal and vertical linear polarization, causes a "loss" of 3 dB, cutting the reported ERP in half. If full-wavelength spacing is used between antenna elements in an array, the ERP is increased approximately in proportion to the number of elements. When half-wave-spaced elements are used (to reduce RF radiation beneath the radio tower, or for other purposes), the increase is less. Null fill also detracts from the ERP by increasing the power in the nulls that form between side lobes. Stations with beam tilt often have two ERPs listed: one at the angle of tilt (the main lobe), and another in the standard horizontal plane. When only one ERP is listed, this is usually referring to the power in the main lobe.
Other articles related to "power, effective radiated power":
... from the CRTC to operate a new low-power FM transmitter at 96.7 MHz in Dalhousie ... It broadcasts on 103.9 MHz using a directional antenna with an average effective radiated power of 7,295 watts and a peak effective radiated power of 15,000 watts (class C) ... in Dalhousie, namely CIMS-FM-1, which broadcasts on 96.7 MHz with an effective radiated power of 8 watts (class LP) using an omnidirectional antenna ...
... Broadcasting Corporation to operate on Channel 6, with an effective radiated power of 3,000 watts (video), and 300 watts (audio) ... station placed a broadcast translator in Fort McPherson (CHAK-TV-1), on Channel 13, with an effective radiated power of 100 watts ... July 3 saw a proposal to decrease power from 3,000 watts to 122 watts ...
... to move to FM on 97.7 MHz with an effective radiated power of 100,000 watts was denied in 1993 ... An application to convert to the FM band on 97.7 MHz with an effective radiated power of 50,000 watts was denied once again on September 11, 2008 ... to convert to the FM dial, again at 97.7 MHz with an effective radiated power of 50,000 watts, which finally received CRTC approval on August 20, 2009 ...
Famous quotes containing the words power and/or effective:
“To play safe, I prefer to accept only one type of power: the power of art over trash, the triumph of magic over the brute.”
—Vladimir Nabokov (18991977)
“The only effective way to help well-intentioned, intelligent persons to do the best they can in raising children is to encourage and guide them always to do their own thinking in their attempts at understanding and dealing with child-rearing situations and problems, and not to rely blindly on the opinions of others.”
—Bruno Bettelheim (20th century)