Gain and Radiation Resistance
If mounted above a perfect ground plane, a quarter wave whip has a gain twice (3 dB greater than) that of a half wave dipole, or 5.19 dBi, and a radiation resistance of 36.8 ohms. However without a ground plane the gain is reduced and the radiation resistance increased. Whips mounted on vehicles use the metal skin of the vehicle as a ground plane. In hand-held devices usually no explicit ground plane is provided, and the ground side of the antenna's feed line is just connected to the ground on the device's circuit board. Therefore the radio itself, and possibly the user's hand, serves as a rudimentary ground plane. Since these are no larger than the size of the antenna itself, the combination of whip and radio often functions more as an asymmetrical dipole antenna than as a monopole. In stationary whip antennas, a "ground plane" consisting of several rods a quarter-wavelength long radiating horizontally from the base of the whip is often used. This type of antenna is called a ground plane antenna.
Read more about this topic: Whip Antenna
Famous quotes containing the words gain and, gain, radiation and/or resistance:
“Throughout the 1980’s, we did hear too much about individual gain and the ethos of selfishness and greed. We did not hear enough about how to be a good member of a community, to define the common good and to repair the social contract. And we also found that while prosperity does not trickle down from the most powerful to the rest of us, all too often indifference and even intolerance do.”
—Hillary Rodham Clinton (b. 1947)
“The west yet glimmers with some streaks of day.
Now spurs the lated traveller apace
To gain the timely inn.”
—William Shakespeare (1564–1616)
“There are no accidents, only nature throwing her weight around. Even the bomb merely releases energy that nature has put there. Nuclear war would be just a spark in the grandeur of space. Nor can radiation “alter” nature: she will absorb it all. After the bomb, nature will pick up the cards we have spilled, shuffle them, and begin her game again.”
—Camille Paglia (b. 1947)
“It was not seen that woman’s place was in the home until she began to go out of it; the statement was a reply to an unspoken challenge, it was attempted resistance to irresistible change.”
—Rose Wilder Lane (1886–1965)