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#6
December 25th 05, 02:18 AM
posted to rec.radio.amateur.antenna
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If the ideal lenght of an antenna is 1/4 Wave lenght then wayare the Car Cellular antennas are longer then this ?
harrogate2 wrote:
"Ralph Mowery" wrote in message nk.net... "tomerbr" wrote in message groups.com... this was a qustion from my instractor in college As Dave said, there is no ideal length for an antenna. The 1/4 wave antenna will have a radiation patern that sends much of the signal at high angles from it. Not usually good for cell phones where they are usually on short towers (if you call a couple of hundred feet short). The longer (in wavelengths) antennas tend to put the signal more to the horizon and not overhead. By modifying the radiation patern to put it more where it is needed instead of where it is not needed you get gain in that direction and hopefully longer range. What an absolute load of blx. The reason that car cellular antennae are longer than a 1/4 wavelength is that almost all of them are centre loaded dual antennas or are 5/8 or 7/8 co-linears. The very short ones are often a little longer as they are coupled through glass and have to be matched. The wavelength of a signal and it's aerial have nothing to do with the propagation pattern. Wha? surely you jest! 73 de Mike KB3EIA - |
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