I have a question (possible bug I found?) about the EMI software package.
I am taking EMI measurements through a 10dB attenuator. Based on the manual I need to set the "Ref Offset" value in the Amplitude menu to match the external attenuator.
When in normal spectrum analyzer setting the "Ref Offset" value does shift the amplitude of the plot by the correct amount. If I enter 10dB the entire curve shifts up by 10dB on the scale.
However, when in the EMI mode setting the "Ref Offset" value shifts everything, including the scale and the limit mask. This means that all the readings and the limit mask for checking EMI emissions levels is incorrect if there is any external attenuator that is corrected via the "Ref Offset" value.
Am I misunderstanding something? The behavior seems to be correct for just spectrum analyzer mode. I looked through all the options specific to the EMI mode and I do not see any alternative way to set a ref offset value. The limit masks can be shifted up or down, but that still means that all the amplitude values are incorrect with an external attenuator.
The behaviour is just the same - when you press calibrate, calibrate, 1-port the frequency range always resets to 100khz to 3.2Ghz.
I have a SVA1032X, born SVA1032X, with SW 3.2.2.4.0 20201220-1 and in this unit the freq does not change
Am I correct in assuming that in such case, after the user calibration (OSLT) has been successfully performed, the status in the upper left of the screen would have to change to Cor (=calibrated)?
Now it shows --- regardless of what I do.
According to the user manual on page 76:
3.5.6 Calibration
Set calibration related items. The calibration status is displayed in the upper left corner of the screen.
The calibration status and display are as follows:
No calibration data --- (displayed in gray)
Calibrated Cor (displayed in blue)
Correction Off Off (displayed in gray)
Need to re-calibrate C? (displayed in blue)
Wow Thanks ! - I guess it was kind of obvious but yes, plugging in a mouse really makes a difference - recommended !
There are still unresolved issues around VNA calibration and saving of calibration.
One has been referred to already by Ghislain
Am I correct in assuming that in such case, after the user calibration (OSLT) has been successfully performed, the status in the upper left of the screen would have to change to Cor (=calibrated)?
Now it shows --- regardless of what I do.
According to the user manual on page 76:
3.5.6 Calibration
Set calibration related items. The calibration status is displayed in the upper left corner of the screen.
The calibration status and display are as follows:
No calibration data --- (displayed in gray)
Calibrated Cor (displayed in blue)
Correction Off Off (displayed in gray)
Need to re-calibrate C? (displayed in blue)
I experience the same - the unit seems to be calibrated (I know this becuase I am calibrating with a known dodgy load and it accounts for it perfectly). But it is disconcerting to see that the status is ---
I did find that if I do 1-port Cal followed by just an "Open" Cal the status changes to "Cor" and the 1-port cal is not lost. So there is another good work around.
It begs the question: What is the point of having a menu option just for "Open" calibration and another for "Short" Calibration when there is none for "Load" Calibration ? I mean if you want to do a calibration you either select "1-port" or "Through" which include all elements.
OK, next problem. When you Save the calibration to a file, switch the instrument off, switch on again, it has lost the calibration. Aha - but you saved it to a file ? Load the file and, yes you guessed it, you have still not got your calibration back. The only answer is to repeat the calibration.
Now this is not a huge problem because I think you probably need to calibrate at every use anyway - especially if you've had the instrument off and come back for another session. But you are supposed to be able to do this and it makes me queasy that if some of these small items don't work, what is there that also doesn't work and that might give you really dodgy results when you don't realise it?
After having read everything I can find, I am now starting to think that this might all be down to the unit being an "upgraded" SSA. Perhaps the firmware is trying to deal with a use case that it wasn't written for - like maybe there isn't a proper factory VNA calibration file and it is getting into a twist as it tries to combine a non-existent file with a user cal file.
I did have a look at the logs and thought I may have the answer but there are log entries to say successful factory vector calibration applied, so it probably isn't that after all. But perhaps something similar that I haven't thought of ?
Regards
Eloso
Also - check you are on the latest firmware?
I am not able to replicate the Save/Load cal issue either.
Thanks everyone.
Yes I am on latest firmware. 3.2.2.4.0.r2 is displayed on the System Screen.
And sorry but no, the answer is not to change the file type to CAL. I have already done this as a matter of course.
Interestingly, loading a saved CAL file does make a difference - ever so slight difference to the display. But it is a long way from being what it should be. I am using a very good 50 ohm load and a fairly dodgy one, in order to give me a reliable baseline and test subject.
I have heard two folk say now that this behaviour is not apparent on their instruments. I am wondering if there is an issue relating to it being an upgraded machine rather than a native born one. It would be really helpful if folk can state if their machine was purchased as an SVA1032X or was transformed into one.
I had no problem with the upgrade and Linux has been part of my career for a long time. I have checked several times and looked at several different (but more or less the same of course) descriptions of the upgrade process so am as confident as it is possible to be that the upgrade went according to plan and should be just like everyone else's. I'm experienced enough also to know that this may not be the case of course and I may have made a mistake.
Cheers
Eloso
There's no improvement over the OSL cal. I tried that as well.
Hi everyone,
I bought an SVA1032X as my first VNA. I have a concern about it though. After a fresh calibration using the "enhanced response" cal, looking into the instrument and measuring the S11 it doesn't seem to be very well matched. Any chance anyone else can confirm this with their unit? The VNAs I've used at work don't have this kind of response so I'm curious as to why mine looks like this.
Hi everyone,
I bought an SVA1032X as my first VNA. I have a concern about it though. After a fresh calibration using the "enhanced response" cal, looking into the instrument and measuring the S11 it doesn't seem to be very well matched. Any chance anyone else can confirm this with their unit? The VNAs I've used at work don't have this kind of response so I'm curious as to why mine looks like this.
I am not a sva1032x owner but the graph seems credible. It represents the s11 of port 2 (which is usually not very efficient in terms of vswr) seen through a transmission line less than a meter long.
It was a nice thought but perhaps we are barking up the wrong tree. Unless there are factory calibration files elsewhere. Rather than comparing file lists from an SSA with a genuine SVA can we compare filelists from a genuine SVA with my upgraded version ? I can do this if someone can provide a full treelist of files from a genuine SVA.