[Elecraft] OT Wullenweber Array

[Fred Jensen]

charliedelta at hushmail.com wrote:
 > Modern DF arrays can fix a position from a single location. Modern
 > DF arrays measure the phase differences very accurately and can use
 > the phase difference to obtain directivity and azimuth.

One of the nice things about email reflectors like this one is that you 
can learn a lot of useful things and also satisfy curiosity about some 
things you have no use for.  Since Eric is allowing the Wullenweber 
discussion to go on despite general non-relevance to anything Elecraft:

What is the difference between "directivity" and "azimuth," save 
possibly that azimuth is referenced to some arbitrary zero direction 
(like North) and directivity maybe isn't?  [teeny factoid: the US 
military aircraft navigation system named TACAN uses a zero direction of 
East -- always wondered why.  Maybe to confuse the enemy?]

How does one obtain a complete set of coordinates for the origin of a 
received signal using only one passive receiving site (i.e. no 
transponder for time delay measurement)?  I understand bearing (azimuth) 
from the rx site ... how does one obtain distance?

I did think PA0SIM's phase coherent K2's was kind of cool.  I don't know 
if the phase shifts are exactly the same across separate K2's, but I 
guess whatever difference there was would be constant and could be 
factored out?

Inquiring minds want to know.

73,

Fred K6DGW
Auburn CA CM98lw