Crossflashed Siglent SSA to SVA shows weird Smith chart  - Page 1
Forum section: electronics / testgear

author: Attenbach
author_rank: Contributor
timestamp: December 09, 2024, 07:28:49 am
content: Sorry for escalating this topic, but I feel it deserves its own thread, in hopes that people in future can find the solution here and to learn what went wrong.TLDR: Crossflashed a brand-new SSA3021X Plus to a SVA1032X to allow characterising passive components. Under no condition, setting, resetting, calibration, DUT, did it show anything but this random noise.My longing after a dot has never been greater. This is my first SA, or VNA for that matter and I have no prior experience/intuition to check for a cause.Other tools available to me: SDS824X HD, basic mutimeter, AC Source, (can borrow function gen)What is going on?PS: it looks like the remaining modes continue to work as advertised..EDIT: title

author: tautech
author_rank: Super Contributor
timestamp: December 09, 2024, 07:35:28 am
content: Thread title is misleading....Siglents real VNA's start with the SNA5000A series.....

author: shabaz
author_rank: Frequent Contributor
timestamp: December 09, 2024, 08:47:23 am
content: Hi,Assuming it's not an equipment/firmware fault, then there's a good chance there's been a fault during calibration.The display should at least show a dot after your calibration with the load applied. If it's not doing that, are you sure your load is OK? Maybe it is broken internally and is open circuit, which would cause the distance between an open and a load to be very small, which may well cause such extreme levels of garbage to be displayed (I'm speculating; I've not accidentally done a faulty calibration like this in a long time).Also, for further improving the chance of a usable display, it's best to set your range to (say) 100 kHz to 10 MHz or 100 MHz or so, if that's the range you're planning to use for your component testing, in case your calibration parts are not performing as well at the higher frequencies (but your display is showing worse than that, hence why I believe it could be a faulty load during calibration).One other thing; you're not accidentally using a reverse SMA (i.e. RP-SMA) plug? That would certainly cause such an issue. Easy mistake to make, I've done that a few times (not with a VNA).

author: Attenbach
author_rank: Contributor
timestamp: December 09, 2024, 03:37:34 pm
content: Thanks a lot for your patience shabaz, I have checked all your points yet again.I can only measure my load with a multimeter, yielding 51 Ohm. My multimeter isn't the best, then again, the load might be that one ohm off. I don't assume it makes that much of a difference (practically 2%) if to be used at low frequencies in the future. Made out of 2x 100Ohm 0805 resistors with the film pointing up to reduce capacitance at the cost of higher background noise sensitivity. The goal was more to verify I can get the instrument to run at all. I don't suspect any wrongdoing from it, but please correct me if am wrong.As you can see in the second picture above, I tried calibrating for 100 kHz - 30 MHz, with the top left blue "Cor" confirming a 1-pt load calibration has been performed by following the 3 steps closely. First open, then short, then load. I checked and pointed on them to be absolutely certain, to no avail.I am only using SMA and I am very cautious when shopping for them in person. I can confirm, I only use SMA. Lastly, I verified that the N-connector to SMA has no defect. I can measure continuity on its line, it is brand new after all.Again, I have never ever seen just a dot or a line since crossflashing, even after factory resetting multiple times. I admit, my linux-and-cmd skills are non-present and I closely followed the tutorial, sometimes with the help of ChatGPT to elaborate on a step (putting the entire outline + descrp. into the prompt), so I cannot cross out my incompetence. Then again, the device otherwise works as expected, showing the VNA mode under Modes and the SVA Firmware in the System Info. If I messed up the files, please let me know what I could have missed. I am willing to screenshare my telnet if someone is intrigued to have a look.Thank you so much! Again, this is my first experience ever with a SA /SVA...