Ad
related to: antenna loading coil diagram pdf
Search results
Results From The WOW.Com Content Network
A common application of loading coils is to improve the voice-frequency amplitude response characteristics of the twisted balanced pairs in a telephone cable. Because twisted pair is a balanced format, half the loading coil must be inserted in each leg of the pair to maintain the balance.
The coil is added at the base of the whip (called a base-loaded whip) or occasionally in the middle (center-loaded whip). In the most widely used form, the rubber ducky antenna, the loading coil is integrated with the antenna itself by making the whip out of a narrow helix of springy wire. The helix distributes the inductance along the antenna ...
A loop antenna is a radio antenna consisting of a loop or coil of wire, tubing, or other electrical conductor, that for transmitting is usually fed by a balanced power source or for receiving feeds a balanced load. Within this physical description there are two (possibly three) distinct types:
With a vertical antenna a loading coil at the base of the antenna may be employed to cancel the reactive component of impedance; small loop antennas are tuned with parallel capacitors for this purpose. An antenna lead-in is the transmission line, or feed line, which connects the antenna to a transmitter or receiver.
The category of simple antennas consists of dipoles, monopoles, and loop antennas. Nearly all can be made with a single segment of wire (ignoring the break made in the wire for the feedline connection). [citation needed] Dipoles and monopoles called linear antennas (or straight wire antennas) since their radiating parts lie along a single ...
Not being close to 3 / 2 wave, this antenna's impedance has a large (negative) reactance and can only be used with an inductive impedance matching network (a tapped loading coil or a so-called antenna tuner). It is a desirable length because such an antenna has the highest gain for any dipole which isn't a great deal longer.
At medium and low frequencies, the high antenna capacitance and the high inductance of the loading coil, compared to the short antenna’s low radiation resistance, makes the loaded antenna behave like a high Q tuned circuit, with a narrow bandwidth over which it will remain well matched to the transmission line, when compared to a 1 / 4 ...
Since the antenna is shorter than the resonant length of one-quarter wavelength, it has capacitance. In order to cancel the capacitive reactance and make it resonant so it can be fed power efficiently, an impedance matching inductor called a loading coil is connected in series with the feedline at the base of the antenna.