Siglent SSA3021X Plus cable calibration? - Page 1
Forum section: electronics / testgear

author: Battle
author_rank: Contributor
timestamp: April 06, 2025, 04:37:21 pm
content: Im not gonna lie, I'm new to having a Spectrum Analyzer like this vs the tinysa ultra.I've been messing with Libre VNA, Measall KC901J & Lite VNA 64. On all of those I've learned to calibrate your cables out for testing devices. Do you do the same with a Spectrum Analyzer like the SSA3021X Plus? I figured you would since it's making measurements on things like duplexers. I don't see anything in the manual about it though. When I google this it seems to show me calibration of the whole unit & not cables.Can anyone explain how or point me to the manual instructions for it? I found the service manual but a word search in there didn't yield results either.If it's not necessary..why isn't it? Seems like various options for test cables could have various losses that would effect readings.

author: tautech
author_rank: Super Contributor
timestamp: April 06, 2025, 08:08:08 pm
content: VNA's and SA's are slightly different beasts.You can do a Through (S21) measurement with a SA providing it has a TG which SSA3000X Plus models have.Reflection (S11) measurements are also possible with a Reflection bridge but unlike a VNA both ports are required.For both measurements TG use is required as stimuli is only available from the TG port.Where in a VNA we would do a Cal before measurement, with a SA the process is slightly different.The TG sweep level inaccuracy is corrected by Normalization where any cable or fitment inaccuracy is also addressed.In SSA3000X Plus the process requires saving the reference sweep then applying Normalise for a flat 0dB trace over the sweep range.Level Offset can also be applied but all settings should be done before the Normalise process.Changing settings later can require the Normalise process to be reapplied, much like is required for VNA's.

author: Battle
author_rank: Contributor
timestamp: April 07, 2025, 12:15:39 am
content: Thanks for the information. I appreciate something to learn from.I do have a wiltron reflection bridge. Only goes to 1ghz, but it's good for my amateur radio uses since I don't mess with anything above 450mhz.

author: tautech
author_rank: Super Contributor
timestamp: April 07, 2025, 04:21:16 am
content: What one must take note of are stimuli levels when using a reflection bridge as they are normally attenuators for reflected signals but have the advantage of providing isolation from RF In.I grabbed a few screenshots for you from SVA1032X which in SA mode works just like your SSA3021X Plus and apart from the higher frequency, they are brothers and more than you might know.Preset was performed and quality N Type cable connected between TG and RF In.TG = ON.Step by step the screenshots demonstrate the process....Experiment with Levels, and Ref Positions and Trace sensitivity (dB/div) to get an idea of how to correct trace/sweep levels to provide the results you need.Have fun.

author: tautech
author_rank: Super Contributor
timestamp: April 07, 2025, 10:59:14 am
content: Quote from: Battle on April 07, 2025, 12:15:39 amThen you will also need to use Reflection mode.This should return S11 measurements.A screenshot of what it looks like from another thread using the same analyzer as yours, a SSA3021X Plus:I can't show you this with my SVA1032X as Reflection mode is deleted and we instead use the VNA mode.

author: Battle
author_rank: Contributor
timestamp: April 07, 2025, 12:03:20 pm
content: I've used the reflection mode before. Seen a video a while back that helped me with learning how to use it. But outside of there I didn't know how to zero out cables for when using the TG & adjusting reject & pass. I didn't realize it was called something else other than calibrate. So I think that's why I wasnt finding what I was looking for when searching on my own.You have been a great help thank you very much.