The Amazon VNAs...

[amdx]

On 12/12/2020 4:46 PM, Cursitor Doom wrote:

On Sat, 12 Dec 2020 09:10:26 -0800 (PST), Brent Locher
blocher@columbus.rr.com> wrote:

Did you get a screen update for this? I have one (thru work) and the screen is very dim, and I think you can get a new screen for about 500
No, I haven\'t bothered yet. I did post a link here a couple of years
ago for anyone else that might be interested, though. But no one
followed up on it.
When the display gets dim and you can\'t correct for it sufficiently in
the settings of the soft menus, there\'s a pot on the transformer you
can turn up that will buy you another five years of use. After that,
it may be time to consider the colour LCD upgrade.

I followed the VNA forum for a while.

https://groups.io/g/nanovna-users/topics
There were some clones that missed the shields and that caused problems.

I don\'t know if they are still being sold, but get educated on which one
you buy, so you\'re not disappointed.

R&L electronics was recommended as carrying one of the well built units.
I\'m bought one.

http://www.randl.com/shop/catalog/product_info.php?products_id=75145
They are out of stock at the moment.

They also have a 350MHz spectrum analyzer for $50. I have done no
research on it,  just figured I\'d wait for the second version,

not sure if it will be better or worse.

                                                  Mikek


--
This email has been checked for viruses by Avast antivirus software.
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[Cursitor Doom]

On Sun, 13 Dec 2020 02:41:12 +0100, Gerhard Hoffmann <dk4xp@arcor.de>
wrote:

I also have an R&S ZVB-8 with a PC3.5 ECAL unit. That ECAL unit
is a great thing. It removes most of the the standards changing.

Continually screwing and unscrewing cal standards is the worst part of
the analysis procedure IMHO (and I assume that to be true for others,
too). Having an ECAL unit saves an enormous amount of time, trouble
and wear on the connectors. Unfortunately, as a hobbyist I can\'t
possibly justify the expense of one.

>But I did not jump far enough, 8 GHz is not enough for me. :-(

I guess that is the worst part of being an RF pro!

Cheers, Gerhard

 

[Jeroen Belleman]

On 2020-12-13 01:57, bitrex wrote:

I\'d like both a LF and HF analyzer but I might move on a 3577 as an
interim solution, it does 5 Hz to 200 MHz, there look to be a couple
for sale within 100 miles for me with the test set included for about
1k, and don\'t have to ship the anchor.

The 3577 goes down to 5Hz, yes, but the test set doesn\'t!
The LF limit of the test set is 100kHz.

Jeroen belleman

 

[Cursitor Doom]

On Sun, 13 Dec 2020 16:53:22 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:

On 2020-12-13 01:57, bitrex wrote:

I\'d like both a LF and HF analyzer but I might move on a 3577 as an
interim solution, it does 5 Hz to 200 MHz, there look to be a couple
for sale within 100 miles for me with the test set included for about
1k, and don\'t have to ship the anchor.

The 3577 goes down to 5Hz, yes, but the test set doesn\'t!
The LF limit of the test set is 100kHz.

Yes, it\'s easy to overlook that. My VNA is extendable up to 6Ghz, but
the matching S parameter test set isn\'t; won\'t do anything over 3Ghz.
Doesn\'t bother me, though, as I don\'t look at anything much over
1300Mhz. In fact anything over half a gig is rocket science to me.

 

[JM]

On 13/12/2020 15:53, Jeroen Belleman wrote:

On 2020-12-13 01:57, bitrex wrote:

I\'d like both a LF and HF analyzer but I might move on a 3577 as an
interim solution, it does 5 Hz to 200 MHz, there look to be a couple
for sale within 100 miles for me with the test set included for about
1k, and don\'t have to ship the anchor.

The 3577 goes down to 5Hz, yes, but the test set doesn\'t!
The LF limit of the test set is 100kHz.

Jeroen belleman

The 35676A goes to 5Hz, and it\'s easy to build a DIY version.

 

[JM]

On 13/12/2020 00:57, bitrex wrote:

On 12/12/2020 12:01 PM, Cursitor Doom wrote:
On Sat, 12 Dec 2020 00:39:32 -0500, bitrex <user@example.net> wrote:

On 12/11/2020 8:17 PM, Cursitor Doom wrote:
On Fri, 11 Dec 2020 00:09:14 -0500, bitrex <user@example.net> wrote:

There are a number of this type of inexpensive VNAs on Amazon, anyone
used one? Is any particular one a favorite or preferable to the
others?
Need to do some vector impedance measurements in the 10-30MHz
range. Thankee

https://www.amazon.com/AURSINC-Analyzer-50KHz-3GHz-Measuring-Parameters/dp/B08G4GXTKK/


Lab grade instruments they certainly ain\'t. However, the obvious ideal
use for them is as cheap tools for students of electronic engineering
to learn all about S-parameters and the Smith Chart. For that much at
least, they\'re unbeatable.


Yeah something like the hp 4191 and 4192 are on my wish list but $8000
isn\'t in my budget at the moment. 70db dynamic range in the low MHz is
probably good enough for what I gotta do.

I got an HP 8753 series VNA with the S parameter test set for just
USD1700. That series enjoys quite a following among pros and serious
amateurs alike so there\'s plenty of advice and support on the io group
forum for them. I think they\'re extendable up to 6Ghz but I won\'t be
needing that as a mere hobbyist.

They all seem to be clones of the same device and the price differences
is just with respect to accessories, screen size, enclosure, and the
general crappy-ness or not of the knockoff.

Nicely put! True though.


I\'d like both a LF and HF analyzer but I might move on a 3577 as an
interim solution, it does 5 Hz to 200 MHz, there look to be a couple for
sale within 100 miles for me with the test set included for about 1k,
and don\'t have to ship the anchor.

https://www.youtube.com/watch?v=PuctX24iAK8

You can find the 8753 used for about $1500 here but don\'t generally
include the test jig/probes/calibration modules for that price and those
seem to run about as much as the box for a set (though I\'ve read you can
DIY some bits to calibrate it.) A full setup that\'s been calibrated by a
reputable used dealer with some kind of warranty seems to run about 5k
for the 8753.

For the frequency band you seem to work in (up to a few 10s of MHz) I\'d
give serious thought to a 4194A. I have the 4191A, 4192A, 4194A, 4195A
and 3577A and the 4194A is pretty much used all the time. It\'s also
maintainable (it\'s replacement isn\'t).

 

[bitrex]

On 12/13/2020 1:17 PM, JM wrote:

On 13/12/2020 00:57, bitrex wrote:
On 12/12/2020 12:01 PM, Cursitor Doom wrote:
On Sat, 12 Dec 2020 00:39:32 -0500, bitrex <user@example.net> wrote:

On 12/11/2020 8:17 PM, Cursitor Doom wrote:
On Fri, 11 Dec 2020 00:09:14 -0500, bitrex <user@example.net> wrote:

There are a number of this type of inexpensive VNAs on Amazon, anyone
used one? Is any particular one a favorite or preferable to the
others?
Need to do some vector impedance measurements in the 10-30MHz
range. Thankee

https://www.amazon.com/AURSINC-Analyzer-50KHz-3GHz-Measuring-Parameters/dp/B08G4GXTKK/



Lab grade instruments they certainly ain\'t. However, the obvious ideal
use for them is as cheap tools for students of electronic engineering
to learn all about S-parameters and the Smith Chart. For that much at
least, they\'re unbeatable.


Yeah something like the hp 4191 and 4192 are on my wish list but $8000
isn\'t in my budget at the moment. 70db dynamic range in the low MHz is
probably good enough for what I gotta do.

I got an HP 8753 series VNA with the S parameter test set for just
USD1700. That series enjoys quite a following among pros and serious
amateurs alike so there\'s plenty of advice and support on the io group
forum for them. I think they\'re extendable up to 6Ghz but I won\'t be
needing that as a mere hobbyist.

They all seem to be clones of the same device and the price differences
is just with respect to accessories, screen size, enclosure, and the
general crappy-ness or not of the knockoff.

Nicely put! True though.


I\'d like both a LF and HF analyzer but I might move on a 3577 as an
interim solution, it does 5 Hz to 200 MHz, there look to be a couple for
sale within 100 miles for me with the test set included for about 1k,
and don\'t have to ship the anchor.

https://www.youtube.com/watch?v=PuctX24iAK8

You can find the 8753 used for about $1500 here but don\'t generally
include the test jig/probes/calibration modules for that price and those
seem to run about as much as the box for a set (though I\'ve read you can
DIY some bits to calibrate it.) A full setup that\'s been calibrated by a
reputable used dealer with some kind of warranty seems to run about 5k
for the 8753.

For the frequency band you seem to work in (up to a few 10s of MHz)  I\'d
give serious thought to a 4194A.  I have the 4191A, 4192A, 4194A, 4195A
and 3577A and the 4194A is pretty much used all the time.  It\'s also
maintainable (it\'s replacement isn\'t).

That looks like a nice one. at $5k for a refurb my wallet will have to
give it serious consideration also

 

[Clifford Heath]

On 14/12/20 12:52 am, amdx wrote:

On 12/12/2020 4:46 PM, Cursitor Doom wrote:
http://www.randl.com/shop/catalog/product_info.php?products_id=75145
They are out of stock at the moment.

They also have a 350MHz spectrum analyzer for $50. I have done no
research on it,  just figured I\'d wait for the second version,
not sure if it will be better or worse.

There is also a wiki and groups.io list for the TinySA.

I saw the early discussion elsewhere before these were set up, and the
designer appears to be competent and to have chosen an approach that can
properly achieve the specifications advertised. So I would buy one of
these in a heartbeat if I didn\'t have a better SA on long-term loan.

<https://tinysa.org/wiki/>
<https://groups.io/g/tinysa/topics>

Clifford Heath.

 

[Chris Jones]

On 13/12/2020 20:43, Clifford Heath wrote:

On 13/12/20 1:05 pm, Gerhard Hoffmann wrote:
Am 13.12.20 um 02:51 schrieb Clifford Heath:

There are several manufacturers of each design, with different
connectors, screens and cases.

The two independent designs (and the one I was working on) share the
same basic approach:
* No filters (only the LPF of a audio-ish zero-IF receivers),
* Two independent generators (for stimulus and LO),
* Toggles between measuring the phase (&phase rate) between the two
generators and the DUT

This approach is very sensitive to any local RF received by the DUT.
I was using two DDS\'s for correlated sine-wave stimulus (and no
switches), whereas these use square-wave stimulus signals.

That\'s much like the DG8SAQ with the 2 DDS. The first versions still
could rely on a printer port and sound card. Quite a long history.

Yes, except Baier\'s VNA used DDS spurs a long way above the fundamental.
Quite a lot like using square waves, but using staircases instead.
Mine uses AD9959, which gives you 4 channels on a 500MHz master clock.

Clifford Heath.

This one is interesting:
https://github.com/jankae/VNA2
although I don\'t really see any advatage in using double-conversion, and
it would have been nicer with 4 receivers, and maybe some separate
buffers in the LO paths of each mixer to provide more RF isolation
between the mixers... otherwise it looks quite good.

 

[Clifford Heath]

On 14/12/20 11:00 pm, Chris Jones wrote:

On 13/12/2020 20:43, Clifford Heath wrote:
On 13/12/20 1:05 pm, Gerhard Hoffmann wrote:
Am 13.12.20 um 02:51 schrieb Clifford Heath:

There are several manufacturers of each design, with different
connectors, screens and cases.

The two independent designs (and the one I was working on) share the
same basic approach:
* No filters (only the LPF of a audio-ish zero-IF receivers),
* Two independent generators (for stimulus and LO),
* Toggles between measuring the phase (&phase rate) between the two
generators and the DUT

This approach is very sensitive to any local RF received by the DUT.
I was using two DDS\'s for correlated sine-wave stimulus (and no
switches), whereas these use square-wave stimulus signals.

That\'s much like the DG8SAQ with the 2 DDS. The first versions still
could rely on a printer port and sound card. Quite a long history.

Yes, except Baier\'s VNA used DDS spurs a long way above the fundamental.
Quite a lot like using square waves, but using staircases instead.
Mine uses AD9959, which gives you 4 channels on a 500MHz master clock.

Clifford Heath.

This one is interesting:
https://github.com/jankae/VNA2
although I don\'t really see any advatage in using double-conversion, and
it would have been nicer with 4 receivers, and maybe some separate
buffers in the LO paths of each mixer to provide more RF isolation
between the mixers... otherwise it looks quite good.

There\'s a discussion of the double conversion receiver in Github issue2
<https://github.com/jankae/VNA2/issues/2>, and also about additional
channels. I agree, the author seems to know what he\'s doing.

CH

 

[LM]

On Fri, 11 Dec 2020 00:09:14 -0500, bitrex <user@example.net> wrote:

There are a number of this type of inexpensive VNAs on Amazon, anyone
used one? Is any particular one a favorite or preferable to the others?
Need to do some vector impedance measurements in the 10-30MHz range. Thankee

https://www.amazon.com/AURSINC-Analyzer-50KHz-3GHz-Measuring-Parameters/dp/B08G4GXTKK/

50kHz-900MHz
https://groups.io/g/nanovna-users/topics
50kHz-3GHz
Two pages because people have already started which the official shop
https://groups.io/g/NanoVNAV2/topics
https://groups.io/g/NanoVNA-V2/topics
All less than 100£$€
https://www.eevblog.com/forum/rf-microwave/