Siglent SVA1015X and SVA1032X 1.5, 3.2GHz Spectrum & Vector Network Analyzers

[tautech]

Yes - you can see how they did this: The signal is very noisy (which is to be expected from those small directional couplers) so they just average multiple measurements. Not ideal, but at least it makes measurements possible. Specs are undoubtedly reduced below 10MHz, but so far, I think good enough for typical HAM use.

hendorog and I looked at this when we got the SVA1015X beta FW and were able to get sub 0.1dB accuracy from his and Siglent VNA Cal kits.

[hendorog]

Yes - you can see how they did this: The signal is very noisy (which is to be expected from those small directional couplers) so they just average multiple measurements. Not ideal, but at least it makes measurements possible. Specs are undoubtedly reduced below 10MHz, but so far, I think good enough for typical HAM use.

hendorog and I looked at this when we got the SVA1015X beta FW and were able to get sub 0.1dB accuracy from his and Siglent VNA Cal kits.

Undoubtedly the coupler is not great down below 3MHz or so. It is well out of its spec'd range. However that is compensated (i.e. hidden from view) by the inbuilt SOL calibration in the device, so you see that as noise on the trace. Other VNA's don't have a built in calibration and on them you can easily see the basic performance of the coupler just by attaching a 50 ohm load.

And of course you can do your own cal to improve it further. And when you do a cal, the magic of the error correction maths makes it a perfect coupler again!

However, when the coupler is operating in this low frequency region where its directivity is poor, what is observed is the noise and also measurement drift increase. The error correction maths amplifies the directivity which is great, but it also amplifies all of bad stuff, like noise and drift, which is bad.

So we see more noise, and the device becomes more sensitive to things like temperature changes. So turning on averaging, having a good warm up and a stable environment help. Doing the calibration and the measurements quickly also matters more in that region.

For HAM use, having the capability to do the measurement is generally more important than the convenience.
With that in mind, there is the option of using an external coupler between port 1 and 2, save the sweeps, and do the calibration on a PC. I am keen for Siglent to support OSL calibrations on Port 2 at some stage to make this a bit easier.

Another point which was raised by member graybeard is that calibration standard sweeps cannot currently be averaged on the device. The SVA just does one sweep and thats it. However if you do the error correction on a PC then you can use averaged sweeps of the calibration standards and then apply the error correction to averaged sweeps of the devices. Obviously that will take longer though, and so there will be a trade-off in drift to get the benefit of reduced noise

[tautech]

Dropping a link to Shahriar's SVA1032X review here:

[tautech]

SVA1032X System info.
VNA and TG options permanent.
Still like SVA1015X with 128 hrs free option trial time. 

[hendorog]

Nice one!

[Mr. Scram]

Is the hardware of the different bandwidth models the same? Or put differently may we expect a hack which would upgrade the lower bandwidth model into a higher bandwidth one?

[graybeard]

The key RF hardware is different, you cannot hack the 1.5GHz model to the 3.2 GHz model.

[Kolos91]

Dear RF gurus!

For my hobby project (Zynq FPGA+ AD/DA + synthesizers,mixers, amplifiers, passives,antennas) I would like to buy either a: SVA1032X or a R&S FPC1500
Since my project is quite general I need all the T&M features I can get and these models offer a lot of them.  SVA1032X has QAM demodulation feature therefore I tend to put my vote on that one, but I have a serious concern. When Shahriar reviewed the instrument he performed QAM demodulation measurements on a saturated amplifier (see attached picture). To me these results make no sense.
When the amplifier gets saturated the constellation points start to move OUTWARDS instead of INWARDS.
It looks like the I and Q components become larger then what they are during non compression. For me this is counter intuitive. I thought the low energy symbols remain (more or less) intact and the high energy symbols at the perimeter of the constellation diagram can't reach their nominal location so their distance from the origin is smaller then during non-compression.
Please tell me why did the instrument displayed what it displayed!

I had bad experience with R&S high end devices in the past. My previous employer bought an FSW85 (1Hz to 85GHz) flagship signal analyzer for hundreds of thousands of euros and some of its software features were so buggy that the usability of the instrument was questionable. So  simply stick to the European quality dogma is not going to help me to make my decision neither. My be there are more folks out there buying an FPC1500 then an FSW85 R&S gets more feedback and has a more stable, bug free firmware then for FSW85. Not like they rushed to fix those bugs I reported them.
So guys what do you think? Which instrument is better for general DIY RF projects?Most likely this will be the only real instrument I buy in my lifetime or at least in the next twenty years so I would like to make the most out of my money.
Have a nice day!


 

[tautech]

Welcome to the forum Kolos91.

FYI there were a couple of issues Shahriar found when doing the video that have since been addressed by Siglent although this new FW version fix is yet to be publicly released. Although I have a copy of this new FW I don't have release notes but I was told by the product manager they were minor/simple fixes. Maybe they were for the QAM sorry I don't know.

Please tell me why did the instrument displayed what it displayed!

Sorry I don't have my SVA units to check your as they are with a beta tester for study of the beta and public release SVA1015X firmware but there are a few members with these units that might give you answers.

For readers the question was for the QAM examples at 44.20:
https://youtu.be/ToVJTKCyIU8?t=2660

[hendorog]

Welcome to the forum!

I believe that a strong point in Siglents' favour is that they have been very receptive to feedback and are actively developing these products.

There are features which have been requested here which have been implemented and bugs reported which have been fixed. There are more improvements coming too.

My interest has been mainly in the VNA feature, and I've seen that feature improve radically, with input from several members here and others.

[tefe]

Dear RF gurus!

For my hobby project (Zynq FPGA+ AD/DA + synthesizers,mixers, amplifiers, passives,antennas) I would like to buy either a: SVA1032X or a R&S FPC1500
Since my project is quite general I need all the T&M features I can get and these models offer a lot of them.  SVA1032X has QAM demodulation feature therefore I tend to put my vote on that one, but I have a serious concern. When Shahriar reviewed the instrument he performed QAM demodulation measurements on a saturated amplifier (see attached picture). To me these results make no sense.
When the amplifier gets saturated the constellation points start to move OUTWARDS instead of INWARDS.
It looks like the I and Q components become larger then what they are during non compression. For me this is counter intuitive. I thought the low energy symbols remain (more or less) intact and the high energy symbols at the perimeter of the constellation diagram can't reach their nominal location so their distance from the origin is smaller then during non-compression.
Please tell me why did the instrument displayed what it displayed!

Actually the high level part (at the four corners, often normalized as 1) of the signal are indeed 'INWARDS'  to those LOW LEVEL PART in the center.

So your question is: why the signal looks 'OUTWARDS' to the reference red dot constellation?
I think the reference red dot constellation is a ideal normalization, while the measured signals are normalized to its RMS average power, which is amplified to saturation (comprssed), so the normalization becomes large?
Sounds logical?

[Kolos91]

Thank you very much!

You explanation perfectly aligns with the measurement results so I think I will go on and buy an SVA1032X
Although if symbols were normalized the opposite way it would be better, but perhaps that only bugs me.

[sm5uiu]

VNA open short load calibration bug ?

Anyone else that has noted this bug 2.2.1.2.2 or am I doing something wrong...

Even if User1 is selected the unit will use info in User2 and vice versa...

/Sam

[tautech]

VNA open short load calibration bug ?

Anyone else that has noted this bug 2.2.1.2.2 or am I doing something wrong...

Even if User1 is selected the unit will use info in User2 and vice versa...

/Sam

Conversation entered via PM's.

[srce]

How accurate are the impedance measurements (E.g. %) with the SVA and over what range (E.g. mOhm to kOhm?)?

[tautech]

New firmware for SVA1000X models

Version 2.2.1.2.5
15 MB
SVA1015X
https://int.siglent.com/upload_file/zip/firmware/Spectrum_analyzer/SVA1015X_2.2.1.2.5_EN.zip

SVA1032X
https://int.siglent.com/upload_file/zip/firmware/Spectrum_analyzer/SVA1032X_2.2.1.2.5_EN.zip

Release notes
Notice:
This firmware must be upgraded from V2.1.1.1.12a or later. If your SVA1000X has an earlier version, please update to V2.1.1.1.12a first and then proceed to update to the latest version.
Improvements:
 Optimize trace, marker, signal track, TG normalization in SA Mode
 Optimize calibration flow, calibration algorithm and sweep speed in VNA Mode
 Optimize web server UI
Solved Issues:
 Fixed video trigger fail, errors in Harmonic measurement in SA Mode
 Fixed admittance error, port extensions error in VNA Mode
 Fixed spectrum amplitude error, meas error, waveform discontinue in MA Mode
 Fixed English help, system message

[borjam]

Thanks for the heads up

It would be great if they elaborated a bit more on those "optimized" features.

So, is it safe to update? From some of your last posts it seems that they now have a beta program.

[tautech]

Transferred from another thread:

Just got my SVA1032X and getting familiar with it.  I have a few questions and don't know if this thread is the right place but here goes:

1) Easyspectrum does not give any control over the VNA (at least not by USB).  Any future plans to provide this remote function?
2) Is there any way to directly save to a PC screen snapshots in VNA mode?  I know I can save png to the SVA1032x internal memory and then copy it to my PC but would be much more functional to control directly to a PC
3) Using Preset and going to VNA the number of data points defaults to 201.  This leads to some very choppy Smith chart graphs.  To get a really smooth Smith plot you need 500-700 data points.  Whats the downside to always using more data points routinely?
4) I have seen screen shots of the SVA1015x serial number and it begins with SVA, I was curious of the significance, if any, of my SVA1032x serial number starting with SSA3?

thanks in advance
Jerry NY2KW

1) Hope so, yes just checked and Mode is not available in V6.
2) Yes using the internal webserver and a LAN connection. There's a dedicated screenshot button that auto saves to your PC browsers download folder.
3) Simply, sweep speed is the penalty especially with wide frequency sweeps. Narrow the sweep to just cover the frequency of interest and it's super fast again and accuracy is enhanced with more data points.
4)That doesn't sound right....like it has the incorrect firmware installed or something. 
Latest version is 2.2.1.2.5, what is your SVA1032X running ?

FYI, the attached screenshot showing Sys Info was grabbed via the webserver straight to my PC.

[NY2KW]

OK, I was able to connect via LAN to the webserver.  This allows front panel control and screenshots.

As to my perhaps unusual serial number, it seems I have the latest firmware.  Attached is a screenshot

[tautech]

As to my perhaps unusual serial number,

Can't check with the factory until they come back from break next week.

Do you have full VNA functionality and all Mode access via the webserver ?
If so, it's nothing to get worried about just yet, still I'll make some inquiries.

[tv84]

"SSA3P" is a S/N from a SSA3000X+.

But, currently, it seems Siglent is mixing the SSA and SVA S/Ns on both equipments.

Maybe because they all use the same FW... 

[bson]

Will this VNA do amplitude sweeps?

[NY2KW]

Do you have full VNA functionality and all Mode access via the webserver ?

So far it seems to.  I am a little disappointed how they implemented VNA User Calibration.  It lets you enter SOL delays but no option to put in a precision load value or the inductance or capacitance of the calibration standard being used.  I use Rosenberger calibration SMA sets as they are quite good and very reasonable cost.  Each set has individual calibration specs for each component of a SOLT calibration - Delay, R, L, C values for the Short, Open and Load.  Also wish they would implement a full 2-port calibration in firmware/memory the way others have even if it means swapping direction manually, at least all 4 S-parameters could be calibrated and then displayed.

[hendorog]

You may already be aware but using external software is the  best way to get full control over the cal - and the models used for the standards.

It would be better if it was built in of course but at least it is possible now using scikit rf for example.

Perhaps it will be added this year. Many improvements to the vna mode were made in the last year.

[NY2KW]

Before buying, I read the manual but it was so brief on VNA module that I made the (poor) assumption that it would provide functionality similar to so many stand-alone PC interfaced VNA's that sell for less than $600.  For example I have SDR-Kits VNWA and it is incredibly robust and rich in features.  I bought the SVA1032x to get away, as much as possible, from being tethered to a PC.  I am not an EE but an advanced hobbyist and I am probably over-reaching on my 'routine' needs so I will hope that Siglent will continue to offer VNA firmware enhancements.

Jerry NY2KW