[Milsurplus] YE - YG considerations

[Hue Miller]

I didn't know this about the YE/YG  :

"However, as range for the YE/YG decreases, the ZB equipment in the aircraft 
will begin to pick up letters in adjacent sectors, but they will be weaker 
than the
correct sector letter. At close ranges, as many as two letters on either 
side of the correct sector may be distinguished."  ( OPNAV 34-P-0800 )

What does it mean when this says the YE "is synchronized with a gyro compass 
so that each letter is beamed from the ship on a true bearing" ?
I am missing what is "true bearing" ?   The ship's not travelling that fast 
that the plane can't follow the beam.

The manual also mentions YJ, "a radar beacon which is operated by certain 
types of airborne radar", and YM similar operation but higher frequency .
I hadn't heard of these two systems before.

I also wonder how far apart they ran these transmitters in the 234-258 MHz 
band. Where more than one was going at a time, like radar picket destroyers 
with YG.
-Hue Miller