[rescue] Radio DF equipment (was Ham radio license question)

[rescue at sunhelp.org]

  This is what I meant.  It DOES use the phase of the 
signal but the name implies that the Doppler shift alone 
is how direction is determined.  The Doppler shift is 
used to obtain this as opposed to a system with fixed 
antennas which have to be manually rotated.  In essence, 
there really is not much of a difference between the two 
systems.  I can imagine that someone could have four 
fixed antennas and measure the phase difference between 
opposite pairs of antennas and calculate direction.  I 
know this is splitting hairs but to some people using a 
Doppler shift is more "magical" than just comparing 
phase.  Next subject is how many angels can dance on a 
Weitek chip.
> 
> So now you have two points and can draw a line on which the noise source
> lies.  I forget exactly how the ramsey kit determines which doppler null
> is the one that points toward the target...I'd have to go dig up the books
> from the basement...but I remember it having something to do with audio
> phasing.