sf1 said:
when frequency is that large doesnt it mean shorter wavelength?
power line can travel 10000km because of extremely low frequency
doesnt it mean that cell phone signals travel very short distance
then?
i dont understand this at all please help
Long wavelength implies a long distance with little phase shift. When
you try to connect the same signal together at many points, like a
power grid, it gets really messy if the waves coming around through
the grid via different paths have different phases where they meet
again. This causes big circulating energy loops in the grid.
Cell phones do not use a grid of conductors, but make use of waves
traveling through space. So the phase is unimportant when the waves
reach a receiving antenna. All the various paths add together, and
some effective phase results. But any phase will do, since the
information being carried by those waves uses many cycles to carry
each bit of information.