PhilSalas, AD5X, gave a comprehensive review of the NanaVNA Plus4 in the April issue of QST. Ther is a statement that "The NanoVNA V2 Plus4 is a true two-port vector network analyzer covering 50 kHz to 4000 Mhz". Doesn't a "true" two port analyzer have the ability to measure he reverse S22 and S12 parameters as well as the forward S11 and S21 parameters. Does the NanaVNA Plus4 have this ability or does one have to use an external transfer relay in conjunction with a third party software?

Mike N2MS

On 3/23/22 6:20 AM, N2MS wrote:
> PhilSalas, AD5X, gave a comprehensive review of the NanaVNA Plus4 in
> the April issue of QST. Ther is a statement that "The NanoVNA V2 Plus4
> is a true two-port vector network analyzer covering 50 kHz to 4000
> Mhz". Doesn't a "true" two port analyzer have the ability to measure
> he reverse S22 and S12 parameters as well as the forward S11 and S21
> parameters. Does the NanaVNA Plus4 have this ability or does one have
> to use an external transfer relay in conjunction with a third party
> software?

Yes and no.

It does in fact measure two port parameters.

No, the test set doesn't swap the ports to get all 4 S-parameters.

I'm not sure what he was referring to as "true" two port analyzer - what
would a non-true analyzer be?  A sweeper/SA which measures only magnitude?

By two port parameters do you mean only S11 and S21?

It could be a question of semanitics. For example the VNWA measures S11 S21 S22 and S12. This is what I would characterize as a "true" two port VNA.

Mike N2MS

> On 03/23/2022 9:36 AM Jim Lux <jim@luxfamily.com> wrote:
>
>
> On 3/23/22 6:20 AM, N2MS wrote:
> > PhilSalas, AD5X, gave a comprehensive review of the NanaVNA Plus4 in
> > the April issue of QST. Ther is a statement that "The NanoVNA V2 Plus4
> > is a true two-port vector network analyzer covering 50 kHz to 4000
> > Mhz". Doesn't a "true" two port analyzer have the ability to measure
> > he reverse S22 and S12 parameters as well as the forward S11 and S21
> > parameters. Does the NanaVNA Plus4 have this ability or does one have
> > to use an external transfer relay in conjunction with a third party
> > software?
>
> Yes and no.
>
> It does in fact measure two port parameters.
>
> No, the test set doesn't swap the ports to get all 4 S-parameters.
>
> I'm not sure what he was referring to as "true" two port analyzer - what
> would a non-true analyzer be?  A sweeper/SA which measures only magnitude?
>
>
>
>
>
>

QUOTE: "A sweeper/SA which measures only magnitude?"

Or spectrum analyzer plus tracking generator.

Both are termed a "Scalar Network Analyzer" (as Jim wrote, magnitude only,
no sign, angle, or complex portion).

Dave - WØLEV

On Wed, Mar 23, 2022 at 1:36 PM Jim Lux <jim@luxfamily.com> wrote:

> On 3/23/22 6:20 AM, N2MS wrote:
> > PhilSalas, AD5X, gave a comprehensive review of the NanaVNA Plus4 in
> > the April issue of QST. Ther is a statement that "The NanoVNA V2 Plus4
> > is a true two-port vector network analyzer covering 50 kHz to 4000
> > Mhz". Doesn't a "true" two port analyzer have the ability to measure
> > he reverse S22 and S12 parameters as well as the forward S11 and S21
> > parameters. Does the NanaVNA Plus4 have this ability or does one have
> > to use an external transfer relay in conjunction with a third party
> > software?
>
> Yes and no.
>
> It does in fact measure two port parameters.
>
> No, the test set doesn't swap the ports to get all 4 S-parameters.
>
> I'm not sure what he was referring to as "true" two port analyzer - what
> would a non-true analyzer be? A sweeper/SA which measures only magnitude?
>
>
>
>
>
>
>
>
>

--
*Dave - WØLEV*
*Just Let Darwin Work*

The NanoVNAs can be properly classified as a 2-port, 1-path VNA.  They have two measurement ports, but only one RF source for thru testing.  So I would say that Phil's statement isn't necessarily wrong, but it is misleading.

If you can get a transfer switch, Joe Smith's software can control the switch it and allow the VNA to measure all four S parameters without changing connections.

Bob,

Thanks for the information. I do have a transfer switch and he installation with the VNA is on the long list of projects.

Mike N2MS

> On 04/22/2022 11:23 PM Bob W0EG <morrisnc7@gmail.com> wrote:
>
>
> If you can get a transfer switch, Joe Smith's software can control the switch it and allow the VNA to measure all four S parameters without changing connections.
>