|
I'm as interested as anyone else who might have one to know the accuracy and reliability of these affordable VNA's, whether nano- or the one from SDR-Kits.
I have a variety of VNA's available but am lacking the SDR-Kits model. Wouldn't it be nice if we knew where it stood compared to the newer nanoVNA's costing a fraction of the price for the same dynamic range and a higher upper frequency limit?
Also, how do the hobby VNA's compare to lab-grade VNA's at HF and up to 1.2 GHz?
If you own an SDR-Kits VNA, can do without it for 3 weeks and trust me to return it to you, please see my offer here:
TNX/73,
John AE5X
--
|
The SDR-Kits software is more refined.? Their calibration kits are of higher mechanical and electrical quality. I use it for things like sorting crystals for ladder crystal filters and LF/HF tasks. I find it more convenient than the HP 3577A (5 Hz - 200 MHz) in many cases. The HP 8702B (a 3 GHz 8753C with the word optical in the description and a slightly different ROM set) compares favorably with the 0-3 GHz specifications of the LibreVNA.? The HP wins in the software capabilities and interface. I am currently using the LibreVNA from 2-6 GHz along with HP 8595E/8596E and a DS Systems tracking generator.? The LibreVNA came with better quality cabling and calibration kit than the NanoVNA variants I have. John, contact me if you are still looking for a SDR-Kits VNWA 3 to borrow. Jimn8qoh On Fri, Jun 25, 2021 at 6:57 PM, John AE5X<ae5x@...> wrote: I'm as interested as anyone else who might have one to know the accuracy and reliability of these affordable VNA's, whether nano- or the one from SDR-Kits. I have a variety of VNA's available but am lacking the SDR-Kits model. Wouldn't it be nice if we knew where it stood compared to the newer nanoVNA's costing a fraction of the price for the same dynamic range and a higher upper frequency limit? Also, how do the hobby VNA's compare to lab-grade VNA's at HF and up to 1.2 GHz? If you own an SDR-Kits VNA, can do without it for 3 weeks and trust me to return it to you, please see my offer here: TNX/73, John AE5X --
|
Hi John,
This sounds like a really nice idea!
I do have a SDR-Kits VNA 3SE, but I won't offer to lend it to you since I am in Sweden.
However, I am interested in following the procedures and results in your shootout,
since I was planning to do something similar myself.
I have access to several of the HPs (8752A 8753D and other) at my work at KTH University.
These are donations and have seen much use, so a I am unsure of how well they work now.
They are not easy to use for students either. This is where a nanoVNA or VNA 3SE would come in handy.
I have also recently ordered a nanoVNA V2 to test along with my nanoVNA H model.
If you can publish calibration and test procedures on your blogspot,
several of us can cooperate to replicate different measurements.
The SDR-kits has only one manufacturer, but I am aware of the "Clone Wars" of the nanoVNAs.
I am not counting on the nanoVNA V2 I ordered to manage 3 or 4.4 GHz until I see it,
and if we have a common test method we can perhaps easier identify bad manufacturers or models,
and compare relevant specs.
Sincerely,
Carl-Mikael
Not a Ham, just a a university professor
|
Thanks for the comments, Jim - and for the potential offer. Yes, they nano 2 docs specifically mention that it cannot be used for measuring crystal parameters. I had been looking at a LibreVNA - I like the upper freq limit and other specs and would like to have shown it to my co-workers (radar techs and engineers) but whoever moderates the io.group evidently didn't see the relevance of a question regarding the ordering process and documentation availability so the plan to purchase evaporated instantly.
I haven't ruled out an SDR-Kits VNA - but I do need to know what I'd be gaining for the extra $$$. That is the purpose of the upcoming comparison, all of which will be with passive devices.
I have an FA-VA5 from them and am well aware of the high quality of these products, typical of what we've come to expect from German engineering (which also applies to my .22 Beeman R9)!
Thanks again and 73,
--
John AE5X
The SDR-Kits software is more refined. Their calibration kits are of higher mechanical and electrical quality.
I use it for things like sorting crystals for ladder crystal filters and LF/HF tasks.
I find it more convenient than the HP 3577A (5 Hz - 200 MHz) in many cases.
The HP 8702B (a 3 GHz 8753C with the word optical in the description and a slightly different ROM set) compares favorably with the 0-3 GHz specifications of the LibreVNA. The HP wins in the software capabilities and interface.
I am currently using the LibreVNA from 2-6 GHz along with HP 8595E/8596E and a DS Systems tracking generator. The LibreVNA came with better quality cabling and calibration kit than the NanoVNA variants I have.
John, contact me if you are still looking for a SDR-Kits VNWA 3 to borrow.
Jimn8qoh
|
If you want to do full two port forward and reverse measurements the VNWA-3SE and LibreVNA supports this feature. The others do not. SDRKits has excellent support and the LibreVNA looks impressive.
Mike N2MS
toggle quoted message
Show quoted text
On 06/26/2021 1:17 PM John AE5X < ae5x@... > wrote:
Thanks for the comments, Jim - and for the potential offer. Yes, they nano
2 docs specifically mention that it cannot be used for measuring crystal
parameters. I had been looking at a LibreVNA - I like the upper freq limit
and other specs and would like to have shown it to my co-workers (radar
techs and engineers) but whoever moderates the io.group evidently didn't
see the relevance of a question regarding the ordering process and
documentation availability so the plan to purchase evaporated instantly.
I haven't ruled out an SDR-Kits VNA - but I do need to know what I'd be
gaining for the extra $$$. That is the purpose of the upcoming comparison,
all of which will be with passive devices.
I have an FA-VA5 from them and am well aware of the high quality of these
products, typical of what we've come to expect from German engineering
(which also applies to my .22 Beeman R9)!
Thanks again and 73,
--
John AE5X
The SDR-Kits software is more refined. Their calibration kits are of
higher mechanical and electrical quality.
I use it for things like sorting crystals for ladder crystal filters and
LF/HF tasks.
I find it more convenient than the HP 3577A (5 Hz - 200 MHz) in many
cases.
The HP 8702B (a 3 GHz 8753C with the word optical in the description and a
slightly different ROM set) compares favorably with the 0-3 GHz
specifications of the LibreVNA. The HP wins in the software capabilities
and interface.
I am currently using the LibreVNA from 2-6 GHz along with HP 8595E/8596E
and a DS Systems tracking generator. The LibreVNA
|
The LibreVNA is available from Zeenko store on AliExpress.? The price is $399 + shipping which was $39 to the US.? They have roughly 30 left out of the 100 initial run.? I see other stores now starting to offer the LibreVNA at $830+850 plus shipping.... I'm not sure if this is scalping or the planned pricing...
I am helping some graduate students who are designing and testing ion thrusters at the university plasma lab.??
The LibreVNA is not a $50K instrument, however it compares favorably with one of the Rigol or Siglent spectrum analyzers that have "network analyzer" features added to it and it is two port.??
The case is CNC cut metal and it is not twitchy when you wave your hands around it.? The cables and standards that came with it are of higher quality than came with the NanoVNA SAA2 I have had contact with.? They are still not the quality of a HP/Agilent calibration kit.
The SDR-Kits units use metrology grade connectors and have higher quality calibration kits available.? They have a European audience and a high technical content in their user group.? One of the members published a how-to book for the unit which is excellent.
Jim
On Sat, Jun 26, 2021 at 4:17 PM, n2msqrp<mstangelo@...> wrote: If you want to do full two port forward and reverse measurements the VNWA-3SE and LibreVNA supports this feature. The others do not. SDRKits has excellent support and the LibreVNA looks impressive.
Mike N2MS
toggle quoted message
Show quoted text
On 06/26/2021 1:17 PM John AE5X < ae5x@... > wrote:
Thanks for the comments, Jim - and for the potential offer. Yes, they nano
2 docs specifically mention that it cannot be used for measuring crystal
parameters. I had been looking at a LibreVNA - I like the upper freq limit
and other specs and would like to have shown it to my co-workers (radar
techs and engineers) but whoever moderates the io.group evidently didn't
see the relevance of a question regarding the ordering process and
documentation availability so the plan to purchase evaporated instantly.
I haven't ruled out an SDR-Kits VNA - but I do need to know what I'd be
gaining for the extra $$$. That is the purpose of the upcoming comparison,
all of which will be with passive devices.
I have an FA-VA5 from them and am well aware of the high quality of these
products, typical of what we've come to expect from German engineering
(which also applies to my .22 Beeman R9)!
Thanks again and 73,
--
John AE5X
The SDR-Kits software is more refined. Their calibration kits are of
higher mechanical and electrical quality.
I use it for things like sorting crystals for ladder crystal filters and
LF/HF tasks.
I find it more convenient than the HP 3577A (5 Hz - 200 MHz) in many
cases.
The HP 8702B (a 3 GHz 8753C with the word optical in the description and a
slightly different ROM set) compares favorably with the 0-3 GHz
specifications of the LibreVNA. The HP wins in the software capabilities
and interface.
I am currently using the LibreVNA from 2-6 GHz along with HP 8595E/8596E
and a DS Systems tracking generator. The LibreVNA
|
One thing to realize about the LibreVNA is that it has no screen.? Your PC or laptop is the display and processor.? The performance I get with a USB 3.0, 16 Gig RAM, four core 3.9 GHz processor machine may be much different than what someone else gets with a "minimum to run Windows" laptop with a 2 GHz, two core atom and 4 Gig of RAM....
Jimn8qoh
|
John: I ordered and received a LibreVNA from R&L Electronics, was pleased at the price ($429 vs $599 at Amazon), ordering and delivery, and quality of the unit. The software is a work in progress but the version I am using (1.1.2) seems stable and reasonably intuitive.
I believe that the weakness of the unit is the provided calibration standards and their definitions; I am using the values on the attached document and they seem to work well up to 4GHz, but quickly fall apart above that. I am considering purchasing calibration standards from SDR-Kits which I understand are made by Rosenberger. I also plan to measure the provided standards on a commercial VNA and use the S1P/S2P files as standards definitions; the LibreVNA software will accept measured data for the cal standards in lieu of L/C/Z/delay coefficients.
I also noticed that the LibreVNA runs hot, with the internal temperatures reporting as ~53-56¡ãC; I have obtained a fan-cooled heatsink and some thermal interface material and plan to install then and see the results. However I do not see any temperature-related drift or other issues, coming from a semiconductor reliability background I just prefer to have things run cooler.
I am currently using the LibreVNA to evaluate components for a project at work (L-band beacon receiver with VHF IF) and the measurements I am getting compare favorably with the measurements from a Keysight Field Fox analyzer.
I suspect that when I get adequate calibration standards and definitions I will be quite pleased with the performance of the unit; it is already proving useful in my work.
73, Don N2VGU
|
I paid more for a good used HP 85032B N calibration kit for my 8702B than for the LibreVNA.
The LibreVNA has a spectacular price performance ratio and decent specifications to 3GHz, 3-6 GHz is a bonus and it certainly works well enough to be useful.
The software V1.1.2 with firmware 5 is usable if not full featured.??
What tests would one choose to compare VNA'S?? Sweep a filter, impedance match a device, measure cable length, ...?
I suspect the majority of NanoVNA users use them at HF unless testing antennas...
Jimn8qoh
On Sun, Jun 27, 2021 at 10:15 AM, Donald S Brant Jr<dsbrantjr@...> wrote: John:? I ordered and received a LibreVNA from R&L Electronics, was pleased at the price ($429 vs $599 at Amazon), ordering and delivery, and quality of the unit.? The software is a work in progress but the version I am using (1.1.2) seems stable and reasonably intuitive.
I believe that the weakness of the unit is the provided calibration standards and their definitions; I am using the values on the attached document and they seem to work well up to 4GHz, but quickly fall apart above that. I am considering purchasing calibration standards from SDR-Kits which I understand are made by Rosenberger.? I also plan to measure the provided standards on a commercial VNA and use the S1P/S2P files as standards definitions; the LibreVNA software will accept measured data for the cal standards in lieu of L/C/Z/delay coefficients.
I also noticed that the LibreVNA runs hot, with the internal temperatures reporting as ~53-56¡ãC; I have obtained a fan-cooled heatsink and some thermal interface material and plan to install then and see the results.? However I do not see any temperature-related drift or other issues, coming from a semiconductor reliability background I just prefer to have things run cooler.
I am currently using the LibreVNA to evaluate components for a project at work (L-band beacon receiver with VHF IF) and the measurements I am getting compare favorably with the measurements from a Keysight Field Fox analyzer.
I suspect that when I get adequate calibration standards and definitions I will be quite pleased with the performance of the unit; it is already proving useful in my work.
73, Don N2VGU
|
On 6/27/21 10:36 AM, Jim Cotton via groups.io wrote: I paid more for a good used HP 85032B N calibration kit for my 8702B than for the LibreVNA.
The LibreVNA has a spectacular price performance ratio and decent specifications to 3GHz, 3-6 GHz is a bonus and it certainly works well enough to be useful.
The software V1.1.2 with firmware 5 is usable if not full featured.
What tests would one choose to compare VNA'S?? Sweep a filter, impedance match a device, measure cable length, ...?
I suspect the majority of NanoVNA users use them at HF unless testing antennas...
Jimn8qoh Stuff you can do with some VNAs sweep a filter with many sections and narrow bandwidth (i.e. lots of envelope delay) sweep a crystal (sort of like above) testing an amplifier looking for a "small" mismatch in a long cable (i.e. put a tiny mismatch 10 meters from the end of a 30 meter cable with a fairly good load) with synthetic TDR measuring transformers and extracting parameters, particularly in a 4 port scenario (i.e. a transformer with two center tapped windings) measuring impedances that are a LONG way from 50 ohms (i.e. measuring small changes in reflection coefficient near 1) measuring mixers (lots of ways to do this with a two port analyzer) Some of this is more about calibration and stability than the raw SNR performance
|
Jim: The optimal way would be to measure several standard articles on each
test analyzer and compare the S2P files from each instrument.
The classical verification/transfer standards are a Beatty mismatch
standard which is a section of 25¦¸ air line between 50¦¸ air line sections,
a 50¦¸ air line and one or more attenuators with different values, typically
one with a relatively low value and one with a higher attenuation. The
air line standards are expensive and easily damaged:
Please note that measuring one or more of the same standards used for
calibration will tell you little about the calibration quality, only the
connection repeatability.
I have found that measuring a filter with passband and stopband within the
calibrated frequency range as a quick check gives pretty useful information
about the instruments in terms of directivity and transmission dynamic
range.
But instrument verification is an entire specialty within the science of
metrology.
73, Don N2VGU.
toggle quoted message
Show quoted text
On Sun, Jun 27, 2021 at 1:46 PM n8qoh@... <n8qoh@...> wrote: I paid more for a good used HP 85032B N calibration kit for my 8702B than
for the LibreVNA.
The LibreVNA has a spectacular price performance ratio and decent
specifications to 3GHz, 3-6 GHz is a bonus and it certainly works well
enough to be useful.
The software V1.1.2 with firmware 5 is usable if not full featured.
What tests would one choose to compare VNA'S? Sweep a filter, impedance
match a device, measure cable length, ...?
I suspect the majority of NanoVNA users use them at HF unless testing
antennas...
Jim
n8qoh
Sent from Yahoo Mail on Android
<>
On Sun, Jun 27, 2021 at 10:15 AM, Donald S Brant Jr
<dsbrantjr@...> wrote:
John: I ordered and received a LibreVNA from R&L Electronics, was pleased
at the price ($429 vs $599 at Amazon), ordering and delivery, and quality
of the unit. The software is a work in progress but the version I am using
(1.1.2) seems stable and reasonably intuitive.
I believe that the weakness of the unit is the provided calibration
standards and their definitions; I am using the values on the attached
document and they seem to work well up to 4GHz, but quickly fall apart
above that. I am considering purchasing calibration standards from SDR-Kits
which I understand are made by Rosenberger. I also plan to measure the
provided standards on a commercial VNA and use the S1P/S2P files as
standards definitions; the LibreVNA software will accept measured data for
the cal standards in lieu of L/C/Z/delay coefficients.
I also noticed that the LibreVNA runs hot, with the internal temperatures
reporting as ~53-56¡ãC; I have obtained a fan-cooled heatsink and some
thermal interface material and plan to install then and see the results.
However I do not see any temperature-related drift or other issues, coming
from a semiconductor reliability background I just prefer to have things
run cooler.
I am currently using the LibreVNA to evaluate components for a project at
work (L-band beacon receiver with VHF IF) and the measurements I am getting
compare favorably with the measurements from a Keysight Field Fox analyzer.
I suspect that when I get adequate calibration standards and definitions I
will be quite pleased with the performance of the unit; it is already
proving useful in my work.
73, Don N2VGU
|
On Sun, 27 Jun 2021 at 20:22, Donald S Brant Jr <dsbrantjr@...> wrote: Jim: The optimal way would be to measure several standard articles on each
test analyzer and compare the S2P files from each instrument
I'm not convinced that tells you anything useful, unless one is known to be good. A lot of these VNAs are copying code from another, so I would not trust that. The classical verification/transfer standards are a Beatty mismatch standard which is a section of 25¦¸ air line between 50¦¸ air line sections,
a 50¦¸ air line and one or more attenuators with different values, typically
one with a relatively low value and one with a higher attenuation. The
air line standards are expensive and easily damaged:
My company produces kits with one verification attenuator. It is not as good as a Beatty line, or airline, but it produces something that can be verified. One customer with an R&S VNA got very different results on the attenuator to those we supplied.
Please note that measuring one or more of the same standards used for
calibration will tell you little about the calibration quality, only the
connection repeatability.
Yes, I once demonstrated to someone that a 22 ohm wire-wound resistor could be used as a calibration standard. If that's defined to be 50 ohm in the calibration routines, then it will show a very high return loss if you measure that same 22-ohm wire-wound resistor. If you then connect a high quality 50 ohm load, it will look awful. I have found that measuring a filter with passband and stopband within the calibrated frequency range as a quick check gives pretty useful information
about the instruments in terms of directivity and transmission dynamic
range.
But instrument verification is an entire specialty within the science of
metrology.
METAS have published a lot on that, as have NPL. 73, Don N2VGU. Dr David Kirkby Ph.D C.Eng MIET Email: drkirkby@... Web: Kirkby Microwave Ltd (Tel 01621-680100 / +44 1621-680100) Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT.
|
A while back I had a go at dumping out a full 2 port model of a VHF BPF using the nanovna and also a lab VNA to see how the results compared. Although this only tested up at VHF I thought the results compared quite well for insertion loss and complex impedance. I don't really plan to use my early nanovnaH above 300MHz and will probably only use it up to 50MHz most of the time but I do think the performance is excellent up to 50MHz. As with any VNA a lot depends on the cal kit and the test fixture and I used a decent homemade SMA mechanical kit with the nanoVNA and an ecal cal module with the lab VNA.
See the image below to see how the two VNAs compared for this simple BPF test. The initial aim here was really to see if my nanovna software was working correctly for s11 s21 s12 s22 data dumping (with a fixture swaparound). I was also quite pleased with how well the results agreed between the two VNAs.
|
Carl-Mikael Zetterling
Donald S Brant Jr
Dr. David Kirkby, Kirkby Microwave Ltd
