how does the magnetic field.....

[alanveron]

produced by the earth affects or interference the communication system?

[shrumeo]

it doesn't much that i know of
it actually protects us from a lot of potentially interfering radiation from the sun

[pnjabiloafer]

well, i don't think that it does either. It extends way into space, and i don't believe we have any satellite's which extend that far into space.. so there wouldn't be any reason for interference, ;)

[Nereid]

produced by the earth affects or interference the communication system?The characteristics of the ionosphere - which plays a big part in how radio signals are propogated - are influenced by the solar wind. The Earth's magnetic field significantly affects the impact of this wind on the ionosphere. How much of modern communications still uses ionospheric reflection (etc)?

Higher up, communications satellites are built to withstand a certain amount of radiation damage, principally from the solar wind. The Earth's magnetic field creates zones of high radiation (Van Allen belts) by trapping solar wind particles. When solar wind/Earth's magnetic field conditions are right (or wrong!), a satellite may receive more radiation than it was designed to handle, and may malfunction or fail.

So, 'how does the Earth's magnetic field affect communications systems?' In many ways, but only indirectly.