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The driven elements between the UHF and VHF are then coupled and often matched for a 75 Ω coaxial downlead to the receiver. When a "driven element" is referred to in an antenna array, it is often assumed that other elements are not driven (i.e. passive radiator) and that the array is tightly coupled (spacing far below a wavelength).
In same-band repeaters, isolation between transmitter and receiver can be created by using a single antenna and a device called a duplexer. The device is a tuned filter connected to the antenna. In this example, consider a type of device called a band-pass duplexer. It allows, or passes, a band, (or a narrow range,) of frequencies.
This reflective array television antenna consists of eight "bowtie" dipole driven elements mounted in front of a wire screen reflector. The X-shaped dipoles give it a wide bandwidth to cover both the VHF (174–216 MHz) and UHF (470–700 MHz) bands. It has a gain of 5 dB VHF and 12 dB UHF and an 18 dB front-to-back ratio.
The IEEE defines the UHF radar band as frequencies between 300 MHz and 1 GHz. [3] Two other IEEE radar bands overlap the ITU UHF band: the L band between 1 and 2 GHz and the S band between 2 and 4 GHz. UHF television antenna on a residence. This type of antenna, called a Yagi–Uda antenna, is widely used at UHF frequencies.
An antenna array (or array antenna) is a set of multiple connected antennas which work together as a single antenna, to transmit or receive radio waves. [ 1 ] : p.149 [ 2 ] The individual antennas (called elements ) are usually connected to a single receiver or transmitter by feedlines that feed the power to the elements in a specific phase ...
This mast has two UHF antennas for receiving signals from different directions. The lower antenna is a bowtie array. The upper antenna is a Yagi design. UHF television broadcasting is the use of ultra high frequency (UHF) radio for over-the-air transmission of television signals. UHF frequencies are used for both analog and digital television ...
The dish antenna occupies the high frequencies (typically 950 to 1450 MHz), and the TV antenna uses lower television channel frequencies (typically 50 to 870 MHz). In addition, the satellite also gets a DC to low frequency band to power the dish's block converter and select the dish antenna polarization (e.g., voltage signaling or DiSEqC ).
Inherently an antenna diversity scheme requires additional hardware and integration versus a single antenna system but due to the commonality of the signal paths a fair amount of circuitry can be shared. Also with the multiple signals there is a greater processing demand placed on the receiver, which can lead to tighter design requirements.