On 24 Dec 2005 03:15:26 -0800, "tomerbr"
wrote:

If the ideal lenght of an antenna is 1/4 Wave lenght then way are the
Car Cellular antennas are longer then this ?

this was a qustion from my instractor in college

You have been sidetracked into answering the question, when the
premise that "the ideal length of an antenna 1/4 wavelength" is
unsupported and questionable?

On what basis does your instructor make this general assertion?

You could equally be trying to answer the question "If the ideal
length of an antenna is 1/4 Wave length then why Medium Wave broadcast
antennas commonly longer then this?"

What you learn in answering the question will be useful, but you will
also learn that, subject to the meaning of the term "ideal", the
assertion is unfounded, it does not apply in general.

It is equally valid to turn it around and ask that given so many
antennas are not quarter wavelength, is quarter wavelength really
ideal?

Owen

PS: several reasons come to mind why car cellular antennas are not
quarter wave ground plane antenns, they are (over here) multi-band,
they are often so-called ground independent designs (on-glass, gutter
mounts etc) with elevated feed points, they seek higher gain, some are
a metre long for rural coverage, they appeal to buyers who think
bigger is better.



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