[R-390] OT: Antenna question

[Richard.McClung@Dielectric.spx.com]

The Polarization of Ionospheric Waves is a Function of Magnetic Latitude. 

A wave entering the ionosphere typically separates into two waves because 
of the interaction of the free electrons in the ionosphere and the earth's 
magnetic field.  The two waves are called the ordinary (o-) and the 
extraordinary (x-) waves. When the direction of propagation is along or 
parallel to the earth's magnetic field, the two waves are circularly 
polarized, in opposite senses. When the direction of propagation is 
transverse to the earth's magnetic field, the electric field of the o- 
wave is polarized parallel to the earth's magnetic field and the electric 
field of the x- wave is polarized perpendicular to the earth's magnetic 
field. In the splitting of the two waves the MOF of the x- wave is 
typically higher than the MOF of the o- wave. In general the o- wave is 
the dominate wave having less attenuation through the ionosphere compared 
to the x- wave. 

In the Northern Magnetic Latitude the o- wave travels up from the 
transmitter in a right hand elliptical polarization (REP) mode and arrives 
down to the receiver in a left hand elliptical polarization (LEP) mode and 
is typically the strongest wave. The x- wave  travels up from the 
transmitter in the LEP mode and arrives down to the receiver in the REP 
mode.

At the Magnetic Equator the o- wave is linearly polarized along the 
magnetic NS for a wave travelling up or down (transmit or receive). The 
linear polarization for the x- wave is along the magnetic EW for a wave 
travelling up or down (transmit or receive).

In the Southern Magnetic Latitude the o- wave travels up from the 
transmitter in the LEP mode and arrives down to the receiver in the REP 
mode and again is typically the strongest wave. The x- wave  travels up 
from the transmitter in the REP mode and arrives down to the receiver in 
the LEP mode.

RICH  @B> }