With -20 dB from my external Siglent attenuator (20dB@4GHz) the SSA2021X should not be damaged till +50dBm ? Or is this false?
There should be no problem connecting the output of the SSA2021X's tracking gen to the SSA2021X's input. Usually this is how you calibrate it anyway.
I can see direction being an issue with some high power attenuators, but not with a 1W one or less.
Here (see attached picture) are two of my 20 dB, 50Ω which covers a frequency range till 4GHz. One slim (with BNC connectors) for 1W (30 dBm ?) and a fat one for 10W. If I understand you right, I should not use the 10W attenuator as input protection for my SSA2021X?
There should be no problem connecting the output of the SSA2021X's tracking gen to the SSA2021X's input. Usually this is how you calibrate it anyway.
That was my first thought, but the many warnings I found on the Internet about spectrum analyzers confused me.
Once you go to just RF In signals you need be more careful as even a mobile phone nearby handshaking with a cell tower can send input levels beyond safe levels where you will be warned by the internal overload buzzer and OSD warnings. This is especially true when you have the Preamp set to ON which is when you need work with care.
I don't know your environment, if you have a hobby room surrounded by your family who each have a cell phone then the power you get in at an unfavorable time can be quite high.
Also if you have radio amateurs nearby the power if you mount an antenna on your SA can be a problem.
The point is, that you work "wisely", better to work with -20dB first, see if you can make sensible measurements, too much in the noise, then if you do not see very strong signals, use the -10dB attenuator.
I don't know your environment, if you have a hobby room surrounded by your family who each have a cell phone then the power you get in at an unfavorable time can be quite high.
Also if you have radio amateurs nearby the power if you mount an antenna on your SA can be a problem.A few iPhones are flying around near me. And the neighbors next to and below me will also use smartphones. No radio amateurs as far I know.The point is, that you work "wisely", better to work with -20dB first, see if you can make sensible measurements, too much in the noise, then if you do not see very strong signals, use the -10dB attenuator.This annoys me as a spectrum analyzer beginner - the thing is apparently so sensitive that you have to handle it with kid gloves. An oscilloscope is a much more robust part, especially if you use a differential probe (and do not need to cover a common ground). I'm honestly disappointed with the SSA use cases shown in YouTube videos. I can do a lot of antenna-related things much more relaxed with my NanoVNA-F V2, and other things with my SDR boxes. Above all, the FM and AM demodulation function on the SSA is a joke (completely unnecessary in my opinion). And then I now have a TinySA Ultra - which in one of the videos even offers a smaller noise floor. I know I can not compare a TinySA Ultra with a Siglent SSA2021X , but ....
You can get a lower noise floor by turning the resolution bandwidth down. (The tradeoff is that it'll take longer to sweep).
I did my own testing with my SSA2021X and TinySA Ultra using a test signal from my SDG 1032X.
The signals were clearly visible on the TinySA Ultra out of the box. With the SSA2021X, the signal was also visible after various adjustments, but with significantly more noise. The signal/noise ratio seems scary to me as a layman. I tried to set the SSA2021X using various options so that I could see the test signal better on the display. As a test signal I used a simple 10 MHz sine wave signal with 1 to 5 dBm output level (SDG 50 ohm output mode).
To protect the SSA, I installed a 30 dB attenuator (10 W) plus a DC blocker. I reduced the internal attenuation to 0 dB (after the signal-to-noise ratio didn't improve much). Which doesn't make it much better. Then when I activated the internal preamp, the SSA beeped and warned of an overload situation. What crap. The SSA is specified as a maximum of 30 dBm and 50 V DC. Of course, these values are only given for special settings.
BUT - I had used a maximum of a 5dBm signal with 30dB of external attenuation, which corresponds to a -25dBm signal. How can a -25dBm signal produce an overload warning on the SSA? I only activated the PreAmp option under “Amplitude” without setting a manual value. Shouldn't the software prevent overload?
Instead you should let the SA manage internal attenuation and add external attenuators when/if necessary.
External attenuation can then be nulled/corrected with use of the amplitude offset feature.
Instead you should let the SA manage internal attenuation and add external attenuators when/if necessary.
External attenuation can then be nulled/corrected with use of the amplitude offset feature.
I assumed that the spectrum analyzer internal attenuation is one of the tunable parameters of a spectrum analyzer, which should be adjusted by the User if necessary, and the external attanuators are intended to protect the spectrum analyzer from power overload (worst case destruction). Since in many cases you don't know exactly how high the signal level to be measured is (dynamic range of the signal), I assumed that you always have to attenuate a little more generously in order to protect the device.
Certainly so depending on what you are doing however don't underestimate how sensitive a SA is, easily equivalent to any radio.
Certainly so depending on what you are doing however don't underestimate how sensitive a SA is, easily equivalent to any radio.A measuring device that declares a max input level of 30 dBm and then issues an overload warning when the signal is -55 dB (E -5) weaker is suspect to me. And if a internal preamplifier activation in a menu can kill the device - such an option should not be able to be activated or should turn off by itself if it get critical. Surely that should be possible with such an expensive measuring device?
And let's assume that I'm too stupid to be able to display the signal sensibly on the SSA2021X , then the automatic function "Auto Tune" - offered in a separate button - should be able to display a measurement signal reasonably sensibly (signal-to-noise ratio) and not as a small bump surrounded by a sea of noise. And why is this all possible out of the box for a device that only costs a fraction?
Once you go to just RF In signals you need be more careful as even a mobile phone nearby handshaking with a cell tower can send input levels beyond safe levels where you will be warned by the internal overload buzzer and OSD warnings. This is especially true when you have the Preamp set to ON which is when you need work with care.
In many cases an "overload" indication doesn't mean a damaging-level input, but just that the input level with the current attenuation and gain settings results in a signal that is causing the detector to clip or distort. It's not an input power problem, just a dynamic range problem that can be corrected by adjusting the attenuation or gain settings. No harm done.