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It is the most often cited of the COST 231 models (EU funded research project ca. April 1986 – April 1996), [1] also called the Hata Model PCS Extension. This model is the combination of empirical and deterministic models for estimating path loss in an urban area over frequency range of 800 MHz to 2000 MHz.
For very low-power systems, such as mobile phones, signal strength is usually expressed in dB-microvolts per metre (dBμV/m) or in decibels above a reference level of one milliwatt . In broadcasting terminology, 1 mV/m is 1000 μV/m or 60 dBμ (often written dBu). Examples. 100 dBμ or 100 mV/m: blanketing interference may occur on some receivers
Free-space loss increases with the square of distance between the antennas because the radio waves spread out by the inverse square law and decreases with the square of the wavelength of the radio waves. The FSPL is rarely used standalone, but rather as a part of the Friis transmission formula, which includes the gain of antennas. [3]
For example, an FM radio station which advertises that it has 100,000 watts of power actually has 100,000 watts ERP, and not an actual 100,000-watt transmitter. The transmitter power output (TPO) of such a station typically may be 10,000–20,000 watts, with a gain factor of 5–10× (5–10×, or 7–10 dB ).
For example, a "2 by 4" wood stud wall with drywall on both sides results in about 6 dB loss per wall at 2.4 GHz. [2] Older buildings may have even greater internal losses than new buildings due to materials and line of sight issues. Experience has shown that line-of-sight propagation holds only for about the first 3 meters.
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CPP is the cost of an advertising campaign, relative to the rating points delivered. In a manner similar to CPM, cost per point measures the cost per rating point for an advertising campaign by dividing the cost of the advertising by the rating points delivered. [4] The American Marketing Association defines cost-per-rating-point (CPR or CPRP) as:
Fractions such as 1 ⁄ 3 are displayed as decimal approximations, for example rounded to 0.33333333. Also, some fractions (such as 1 ⁄ 7 , which is 0.14285714285714 ; to 14 significant figures ) can be difficult to recognize in decimal form; as a result, many scientific calculators are able to work in vulgar fractions or mixed numbers .