Electronic Communication Systems 2nd Edition by Roy Blake

تمرين 43

Explain each of the following:
(a) AM radio broadcast stations must often reduce power at night to avoid interference.
(b) CB radio at 27 MHz is intended for local communication but can often communicate for hundreds of kilometers.
(c) HF communications are often severely disrupted when the aurora borealis (northern lights) is visible.
(d) Sometimes VHF signals appear and cause interference hundreds of kilometers away from their intended route.
(e) It is possible to communicate somewhat further than the visible horizon using UHF signals.