[Towertalk] Antenna analysers

[mdg]

Hi;

As I am still going back and forth between MFJ269 and VA-1 when
contemplating my next ant. anal. purchase, here are some questions to
those of you who know the answers... .
I am posting those questions here as I tend not to rely too heavily on
whatever I hear from the selling party... . 

1.  VA-1   
Autek claims the VA-1 measures impedance up to 1000 ohms. Is it the
impedance as present at the input terminal or measured through
calculations involving known feedline  impedance + other parameters ? 
What is the resolution of their A/D converter ?
Has anyone verified the measurements with known networks hooked up to
the analyser ?

2. MFJ269
Does this instrument sense the sign of the X ? . What type of bridge is
utilized here ?. 
Since there are some preset line impedance values I presume I cannot
measure an  impedance of an unknown (link coupled) LCR network ...
unless I'd first terminate the coupling line with the known impedance
etc etc. 
>From other correspondence I know this thing is darn accurate and not far
away from the HP Vector analyser within it's capabilities but how stable
(time) are those readings ?

I must admit I like the 269 due to its ruggedness but I'd like to have
an instrument that's capable of performing also other RF tasks around
the shack and finally be able to MEASURE at least some of those unknown
impedances/couplings that exist under the chassis... 

I'd appreciate your comments vy much.
Thanks,
73 Art VE3PND