1.25MHz
http://www.ehow.com/list_7279317_types-gsm-antennas.html
How do you convert cellphone gsm frequency to another gsm frequency?"
Antenna hopping is a feature in which the Tx/Rx is passed through all the available antenna paths in a sector. No frequency is changed during antenna hopping. This helps improve performance by providing spatial diversity.
Depends on what you mean by high frequency. The rabbit ears antenna used in broadcast TV is a dipole and is used for VHF.
GSM 900: Uplink frequency: 890 - 915 MHz GSM 1800 : Uplink frequency: 1710 - 1785 MHz GSM 1900: Uplink frequency: 1850 - 1910 MHz
High frequency is used because of the the size of antennas used to transmit and receive the communications signal. The higher the frequency the smaller the antenna.
Electrical tilt is a tilt which gives by knob present downward in GSM antenna. It is done for effecting the coverage of antenna. If one GSM antenna overshoots then interference will produce. then we give electrical tilt then front lobe will change and back lobe will not change. so antenna provides coverage in both direction. Electrical tilt is always gives in City. It reduces interference.
The Mechanical Tilt is given by physically tilting down the GSM antenna. Tilting downward focuses the beam on a specific area and hence better coverage.
For every frequency there is an antenna that is perfect for radiating at that frequency. Unfortunately, it would be unrealistic to carry a separate antenna for every frequency that a communications center is capable of radiating. To overcome this problem, we use ANTENNA TUNING to lengthen and shorten antennas ELECTRICALLY to better match the frequency on which we want to transmit. Simply put, the antenna does not physically change length; instead, it is adapted electrically to the output frequency of the transmitter and "appears" to change its physical length. Antenna tuning is done by using antenna couplers.
1800mhz
GSM Radio Frequency Unit
900 to 1800MHz