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2. Magnetic switchable device - Wikipedia

   en.wikipedia.org/wiki/Magnetic_switchable_device

   A magnetic switchable device (often called a magnetic base) is a magnetic fixture that uses one or more permanent magnets in a configuration that allows the external field to be turned on or off. They are used in many applications including optics , metalworking , lifting , and robotics, to attach items to metal surfaces in a secure but ...

3. Antenna types - Wikipedia

   en.wikipedia.org/wiki/Antenna_types

   The cone measures near one quarter-wave long along the side from tip to bottom rim, at the antenna's lowest frequency. There is a smaller, flat metal disk mounted horizontally, slightly above the tip of the cone; sometimes the solid disc is replaced by a radiate crown of metal rods, similar to the base of a ground plane antenna. One of the feed ...

4. Antenna (radio) - Wikipedia

   en.wikipedia.org/wiki/Antenna_(radio)

   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

5. Monopole antenna - Wikipedia

   en.wikipedia.org/wiki/Monopole_antenna

   A common type of monopole antenna at these frequencies for mounting on masts or structures consists of a quarter-wave whip antenna with a ground plane consisting of 3 or 4 wires or rods a quarter-wave long radiating horizontally or diagonally from its base connected to the ground side of the feedline; this is called a ground-plane antenna.

6. Whip antenna - Wikipedia

   en.wikipedia.org/wiki/Whip_antenna

   This allows the antenna to be made much shorter than the normal length of a quarter-wavelength, and still be resonant, by cancelling out the capacitive reactance of the short antenna. This is called an electrically short whip. The coil is added at the base of the whip (called a base-loaded whip) or occasionally in the middle (center-loaded whip).

7. Counterpoise (ground system) - Wikipedia

   en.wikipedia.org/wiki/Counterpoise_(ground_system)

   Inverted-L antenna with counterpoise, in a powerful amateur radio station, Colorado, 1920. The counterpoise is the lower grid of horizontal wires, suspended below the antenna. The largest use of counterpoises is in transmitters on the low frequency (LF) and very low frequency (VLF) bands, as they are very sensitive to ground resistance. [2]

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9. Tower Mounted Amplifier - Wikipedia

   en.wikipedia.org/wiki/Tower_Mounted_Amplifier

   A Tower Mounted Amplifier (TMA), or Mast Head Amplifier (MHA), is a low-noise amplifier (LNA) mounted as close as practical to the antenna in mobile masts or base transceiver stations. A TMA reduces the base transceiver station noise figure (NF) and therefore improves its overall sensitivity ; in other words the mobile mast is able to receive ...