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In telecommunications, the free-space path loss (FSPL) (also known as free-space loss, FSL) is the attenuation of radio energy between the feedpoints of two antennas that results from the combination of the receiving antenna's capture area plus the obstacle-free, line-of-sight (LoS) path through free space (usually air). [1]
The Π pad (pi pad) is a specific type of attenuator circuit in electronics whereby the topology of the circuit is formed in the shape of the Greek capital letter pi (Π). Attenuators are used in electronics to reduce the level of a signal. They are also referred to as pads due to their effect of padding down a signal by analogy with acoustics.
A tube transmitter will contain a tuned output network, most commonly a PI network, that steps the load impedance which the tube requires down to 50 ohms. In each case the power producing devices will not transfer power efficiently if the network is detuned or badly designed or if the antenna presents other than 50 ohms at the transmitter output.
Path loss normally includes propagation losses caused by the natural expansion of the radio wave front in free space (which usually takes the shape of an ever-increasing sphere), absorption losses (sometimes called penetration losses), when the signal passes through media not transparent to electromagnetic waves, diffraction losses when part of the radiowave front is obstructed by an opaque ...
This circuit is used for the general case, all T-pads, all pi-pads and L-pads when the source impedance is greater than or equal to the load impedance. The L-pad computation assumes that port 1 has the highest impedance. If the highest impedance happens to be the output port, then use this figure. Unique resistor designations for Tee, Pi and L ...
Transformers, autotransformers, and baluns are sometimes incorporated into the design of narrow band antenna tuners and antenna cabling connections. They will all usually have little effect on the resonant frequency of either the antenna or the narrow band transmitter circuits, but can widen the range of impedances that the antenna tuner can match, and/or convert between balanced and ...
From the figure the received line of sight component may be written as = {() /}and the ground reflected component may be written as = {() (+ ′) / + ′}where () is the transmitted signal, is the length of the direct line-of-sight (LOS) ray, + ′ is the length of the ground-reflected ray, is the combined antenna gain along the LOS path, is the combined antenna gain along the ground-reflected ...
The Smith chart (sometimes also called Smith diagram, Mizuhashi chart (水橋チャート), Mizuhashi–Smith chart (水橋スミスチャート), [1] [2] [3] Volpert–Smith chart (Диаграмма Вольперта—Смита) [4] [5] or Mizuhashi–Volpert–Smith chart) is a graphical calculator or nomogram designed for electrical and electronics engineers specializing in radio ...