Search results
Results From The WOW.Com Content Network
A "sense antenna" is used to resolve the two direction possibilities; the sense aerial is a non-directional antenna configured to have the same sensitivity as the loop aerial. By adding the steady signal from the sense aerial to the alternating signal from the loop signal as it rotates, there is now only one position as the loop rotates 360 ...
The operator tunes the ADF receiver to the correct frequency and verifies the identity of the beacon by listening to the Morse code signal transmitted by the NDB. [5] On marine ADF receivers, the motorized ferrite-bar antenna atop the unit (or remotely mounted on the masthead) would rotate and lock when reaching the null of the desired station.
Instead of triangulation, a second dipole or vertical antenna can be electrically combined with a loop or a loopstick antenna. Called a sense antenna, connecting and matching the second antenna changes the combined radiation pattern to a cardioid, with a null in only one (less precise) direction. The general direction of the transmitter can be ...
A sense antenna normally consists of a single vertical antenna positioned some distance from the crossed loops, in line with one of the two loops, at a distance about the same as the distance between the two vertical portions of the loop. The sense antenna's output is mixed with the loop it is in-line with, through a switch that allows it to be ...
In electronics, an antenna amplifier (also: aerial amplifier or booster) is a device that amplifies an antenna signal, usually into an output with the same impedance as the input impedance. Typically 75 ohm for coaxial cable and 300 ohm for twin-lead cable. An antenna amplifier boosts a radio signal considerably for devices that receive radio ...
In figure 21, an example is shown of a signal split up to feed multiple low power amplifiers, then recombined to feed a single antenna with high power. [52] Figure 21. Splitter and combiner networks used with amplifiers to produce a high power 40 dB (voltage gain 100) solid state amplifier Figure 22. Phase arrangement on a hybrid power combiner.
A common RDF antenna design is the loop antenna, which is simply a loop of wire with a small gap in the circle, typically arranged to rotate around the vertical axis with the gap at the bottom. [3] Some systems used dipole antennas instead of loops. Before the 1930s, radio signals were generally in the long wave spectrum. For effective ...
The basic concept used a loop antenna, in its most basic form simply a circular loop of wire with a circumference decided by the frequency range of the signals to be detected. When the loop is aligned at right angles to the signal, the signal in the two halves of the loop cancels out, producing a sudden drop in output known as a "null".