[TowerTalk] array matrix measurements

[Rudy Severns]

I've made these kinds of matrix measurements several times since I got my 
hands on a VNA.  It's not too hard and actually a lot of fun.  I've found 
that if I've been careful, the reciprocal measurements are usually within 1% 
or better.  This holds true even when the values themselves are really 
strange, as they can be when there's a parasitic radiator coupling into the 
array.

Usually I do the measurements using only impedance measurements which is 
very straight forward but occasionally I'll use the transmission mode and a 
current transformer to do a direct measurement of coupling.  Both ways seem 
to work fine as long as I pay attention to the details.

73, Rudy