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This is because wavelength is inversely proportional to frequency (wavelength in metres = 299,792,458 / frequency in Hz), and transmitter efficiency is severely degraded if the length of the antenna is shorter than 1/4 wavelength. They used grounded or insulated guyed masts with umbrella antennas, or wire-spans across both valleys and fjords.
An antenna rotator (or antenna rotor) is a device used to change the orientation, within the horizontal plane, of a directional antenna. Most antenna rotators have two parts, the rotator unit and the controller. The controller is normally placed near the equipment which the antenna is connected to, while the rotator is mounted on the antenna ...
Transmit diversity is the use of multiple transmit antennas to achieve reliability in radio communication. [1] It involves using signals that originate from two or more independent sources that have been modulated with identical information-bearing signals and that may vary in their transmission characteristics at any given instant.
A manual transmission (MT), also known as manual gearbox, standard transmission (in Canada, the United Kingdom and the United States), or stick shift (in the United States), is a multi-speed motor vehicle transmission system where gear changes require the driver to manually select the gears by operating a gear stick and clutch (which is usually ...
The antenna feed system or antenna feed is the cable or conductor, and other associated equipment, which connects the transmitter or receiver with the antenna and makes the two devices compatible. [ 1 ] [ 2 ] In a radio transmitter, the transmitter generates an alternating current of radio frequency , and the feed system feeds the current to ...
An antenna tuner, a matchbox, transmatch, antenna tuning unit (ATU), antenna coupler, or feedline coupler is a device connected between a radio transmitter or receiver and its antenna to improve power transfer between them by matching the impedance of the radio to the antenna's feedline. Antenna tuners are particularly important for use with ...
Automated manual transmissions can be semi-automatic or fully-automatic in operation. Several different systems to automate the clutch and/or shifting have been used over the years, but they will generally use one of the following methods of actuation for the clutch and/or shifting: hydraulic or electro-hydraulic actuation, [12] electro-mechanical, [13] pneumatic, [6] [14] [15] electromagnetic ...
The transmission signal of the up-link, of relatively high power (1, 2, or 5 watts for common VSAT equipment) originating from BUC and the very low power received signal power (in the order of μV) coming from the antenna to the LNB receiver unit, in this case are at an angle of 90° relative to each other, are both coupled together at the feed ...