Distance near the skip distance should be used for sky-wave propagation
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A ship- to-ship communications system is plagued by fading. The best solution seems to be the use of
As electromagnetic waves travel in free space, only one of the following can happen to them :
When microwave signals follow the curvature of the earth, this is known as
One of the following consists of no resonant antennas:
Which one of the following terms does not apply to the Yagi-Uda array ?
Top loading is sometimes used with an antenna in order to increase its
Cassegrain feed is used with a parabolic reflector to
A helical antenna is used for satellite tracking because of its
A helical antenna is used for satellite tracking because of its
When electromagnetic waves are propagated in a waveguide
When a particular mode is excited in a waveguide, there appears an extra electric component, in the direction of propagation. The resulting mode is
When electromagnetic waves are reflected at an angle from a wall, their wave-length along the wall is
As a result of reflections from a plane conducting wall, electromagnetic waves acquire an apparent velocity greater greater than the velocity of light in space. This is called the
A signal propagated in a waveguide has a full wave of electric intensity change between the two further walls, and no component of the electric field in the direction of propagation. The mode is
In order to couple two generator to a waveguide system without coupling them to each other, one could not use a
A directional coupler with three or more holes is sometimes used in preference to the two-hole coupler