Ok,

So here is the deal... I have a RigExperten 30 that I have used for years and generally speaking I trust. I just bought (secondhand) a IP60z mini analyzer for field work (the AA30 is HUGE!).

The problem... Readigns between the two are inconsistent, the IP60z basically seems to read SWR about ~.5 units higher than the AA30. It also reads Z as somewhat higher than the IZI reading of the AA30. The trends/dips are the same, and on the "lower" SWR readings its .2-.3 off while as the readings climb it gets worse.

Example 40m of my G5RV jr

6900 mhz (min)
AA30 SWR 1.6 IZI 68
IP60Z SWR 1.6 Z 71

7100 mhz
AA30 SWR 2.7  IZI 82
IP60Z SWR 3.3 Z 122

7400 mhz
AA30 SWR 3.5 IZI 48
IP60Z SWR 4.9 Z 90

My main concern here is that I got the ip60 for field use, and I might live with an SWR of 3.5, but not 5.0 so the difference in accuracy does concern me some. Is there some reason the IP60 might be reading a much higher Z than the AA30? The AA30 breaks it all down to inductance resistance reactance etc so clearly it has better ways of measuring stuff than the IP60 which is just Z but I'm really surprised by the large differences. Then again I don't have much experience with different analyzers.

Thoughts?

Any strong broadcast stations nearby?  They can affect some analyzers more than others and throw the readings off.

A man with one analyzer always know what his antenna system reads.  A man with more than one is never quite sure.  

Quantify nearby... Probably within 15-20miles?

I'm mainly curious as to how the Z vs IZI is calculated or measured by the two units as I "think" this is part of the cause. Or that the IP60z might be damaged.

I don't have any exact numbers for you, nor do I understand exactly how different analyzers actually work other than a basic general understanding.

Take a look at this article.  It was the first I found with a quick search and there are many more discussing these topics.  I read a lot but I'm not an expert.  

http://www.bvarc.org/Tech/BlameItOnIZO.pdf

Does either one have a calibration option? Some meters can be calibrated with open circuit and shorted loads, and/or a standard 50 ohm load or something.

Other than that, about the best I could suggest is to try both in comparison to other meters on some sample loads and see if one or both are off.

They both read a 50ohm dummy load fine. Just different readings on the same antenna.