In most cases, helical antennas are mounted over a ground plane.
2.
The prominent helical antenna received telecommands from a ground station.
3.
Helical antennas can operate in one of two principal modes normal mode or axial mode.
4.
A common form of normal-mode helical antenna is the " rubber ducky antenna " used in portable radios.
5.
A "'helical antenna "'is an antenna consisting of a conducting wire wound in the form of a helix.
6.
One application that has used heatshrink in large quantities since the early 1970s is the covering of fibreglass helical antennas, used extensively for 27 MHz CB Radio.
7.
In the " axial mode " or " end-fire " helical antenna, the dimensions of the helix are comparable to a wavelength.
8.
In radio transmission, circular spacecraft communications, or where the polarisation of the signal may change, so end-fire helical antennas are frequently used for these applications.
9.
For television broadcasting specialized vertical radiators that are mostly modifications of the slot antenna or helical antenna are used : the slotted cylinder, zig-zag, and panel antennas.
10.
There are many ways to make a high-gain antenna-the most common are parabolic antennas, helical antennas, yagi antennas, and phased arrays of smaller antennas of any kind.
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