Siglent SSA3021X may be out of cal and distributor is not responding

[papo]

Hey guys

A few weeks ago, I sent the following email to the distributor who sold me the SSA3021X. So far I have not received any response. This is in contrast to last year, when I had a minor software issue with the instrument and then conversation with said distributor was swift. I have to emphasize though that I have not tried to call or send a followup-email yet, so maybe they "just" overlooked it. Hence I didn't proceed with further testing just yet. Nevertheless, I'm looking for advice in terms of trying to contact the distributor or Siglent directly, and also in terms of putting together a procedure that conclusively validates the calibration, and once this is done, to assess whether this is to be expected after almost 2 years or light use. I'm not getting out the pitchfork, just trying to determine the best course of action.

Regards and thank you, Matt

Hello XXX

I purchased an SSA3021X from you in August 2016. It is a very nice instrument and I recommended it to everyone who asked me about it. After almost 2 years I thought I would check its calibration to make sure things are still OK. Unfortunately, my preliminary results show that amplitude accuracy could be off by up to 3 dB. It is my understanding that this is outside of the specifications of the instrument, but I don't have anything at home to make an accurate measurement so it could be a false alarm.

I will take the instrument to work next week, where I can measure this properly. Hence, I am wondering if there is any calibration protocol; a defined way to test if this instrument is still within spec. My preliminary testing was done with a source at 400 MHz and output powers between 0 and -20 dBm. The power accuracy of my source is not very good, so I cross checked with my Boonton Microwattmeter, but that instrument is uncalibrated as well.

For next week's measurement at work, I am planning to use a R&S SMBV100A Vector Signal Source to generate 400 -- 450 MHz CW signals at 0, -10 and -20 dBm and check what my Siglent SA reports. I will also cross-check with a R&S NRP2/NRP-Z81 power meter to eliminate inaccuracies of the source, cable losses etc. My understanding of the specs is that I can expect amplitude accuracy within ~0.7 dB. A friend who has the same instrument checked in his lab and for his (new) instrument, this surely is within spec. My reason for writing to you now is to check if you think this test protocol is adequate to determine whether the instrument lost calibration, or if you think/suggest to do extra tests. I'm also wondering if you think this is normal.

Best regards and thank you

Matt

[2N3055]

What is recommended calibration period for SSA3000X series ?

If it is a 1 year, than technically it wouldn't be their problem... You would need to send it in for a calibration, and only if it is in such a state that it cannot be calibrated properly they would need to repair it under warranty...

Although, I also feel  it probably shouldn't have drifted so much.  I might be wrong, I'm no SA expert...


 

[nctnico]

There is nothing for the distributor to respond to in this endless drivel. There is not even a problem!
If you want to get the service manual with the calibration procedure then ask for that. One sentence is more than enough for that.

Always keep in mind that the person on the other side is receiving & answering hundreds of e-mails per day so make sure your e-mail is easy to respond to (IOW: as short and to-the-point as possible).

[G0HZU]

If you want to improve your test setup, I'd advise getting hold of a decent inline 10dB attenuator as this will improve your source match. It doesn't have to be an accurate 10dB attenuator but it should have low VSWR. Then arrange your setup as Sig_gen>>cable>>10dB_Att>>DUT.

If you have a reasonable healthy and modern >=100MHz scope you could test down at (say) 10MHz and use the scope (with a decent 50R input termination) as the calibration check. Adjust the sig gen power so you get 224mVrms for 0dBm on the scope with the cable and 10dB attenuator and 50R termination inline. You ideally need to use the rms detection on the scope especially if the sig gen has harmonics up has high as -30dBc. A scope obviously won't be as accurate as a decent power meter but it should be easily good enough to spot gross errors with your spectrum analyser at lower frequencies like 10MHz.

When you eventually test with the RF power meter I'd still advise keeping the 10dB attenuator inline. It obviously needs to be at the DUT end of the cable rather than the sig gen end of the cable.

[tautech]

@papo
Do you have the latest firmware installed, if not do that before anything else.
There's also an autocal function so please run that for a while too.

https://www.siglenteu.com/service-and-support/firmware-software/spectrum-analyzers/#ssa3000x-series