"tomerbr" wrote in message
oups.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.