[TowerTalk] impedance meter recommendations pse

Jim Lux jimlux at earthlink.net
Thu Dec 28 13:49:05 EST 2006


At 08:24 AM 12/28/2006, Richard \(Rick\) Karlquist wrote:
>Anyone interested in this topic should read the
>recent QST article on the AIM-4170 antenna analyzer.
>The article has a shoot out of this unit vs other
>ham units and even an Agilent NA.  It is a true
>vector analyzer with a narrowband receiver.  Most
>other analyzers are scalar analyzers that use
>the "3 voltmeter method" to determine phase angle
>(which is why they can't determine sign) and use
>a broadband detector, which is susceptable to BC
>interference.  The N2PK design is similar, but you
>have to homebrew it, AFAIK.


Actually, the 3 meter method can determine phase, except you need one 
more volt meters.  That's really the basis of the 6 port network 
approach (6 ports: 1 input, 1 output, 4 measurement ports)

However, as Rick points out, broadband detectors have their limitations.


>I have purchased one of these and am evaluating it.
>I will report on it on the reflector after I have
>some experience with it.
>
>BTW, I work for Agilent and am currently designing a new
>Agilent network analyzer, so I have more than a
>casual interest in these units.

How about one that can do phase measurements to 0.1 degree at 35 GHz 
on single 4 ns pulses <grin> with mag(S21) of 0 to -100dB.





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