Siglent SSA3021X or aeroflex 3251

[trevwhite]

Which do people think is the better SA? Am thinking if the siglent is still hackable it's a great deal but I do not know a lot about them.

Looking for people's thoughts.

Trev

[nctnico]

I'd trust the Aeroflex more to provide the right numbers. Sometimes I needs to do measurements for customers which can have costly consequences when done wrong. This made me want to not buy the Siglent due to the bugs discovered so far.

[trevwhite]

Well I basically need some pre-compliance testing of circuitry. Thinking I just want to look over parts of circuitry to find where noise is coming from. I tested a board in a lab and there were a few bits to sort out so I wanted to be able to investigate further and correct these before going back. I do not want anything to replace a proper lab, its just for investigation.

Were there quite serious measurement errors with the siglent?

[tautech]

Well I basically need some pre-compliance testing of circuitry. Thinking I just want to look over parts of circuitry to find where noise is coming from. I tested a board in a lab and there were a few bits to sort out so I wanted to be able to investigate further and correct these before going back. I do not want anything to replace a proper lab, its just for investigation.

Were there quite serious measurement errors with the siglent?

Of course not.
You needn't listen to the #1 Siglent hater on the forum.
He had a bad experience with an early SDS2204 (not X) some years ago and hasn't got over it.

Otherwise what do you need to know about SSA3021X ?

[trevwhite]

Hi

I want to know if its going to get me sorted for pre-compliance measurements of my circuitry and generally develop my understanding through having a piece of equipment that has a decent enough spec.

Also be nice if they are still hackable to release all the features?

Trev

[tautech]

Hi

I want to know if its going to get me sorted for pre-compliance measurements of my circuitry and generally develop my understanding through having a piece of equipment that has a decent enough spec.

Also be nice if they are still hackable to release all the features?

Trev

I'm fairly sure there's not been any problems with any of the firmware restricting unlocking options and even if there is the community here will soon sort it out.
I'm no real SA wizz but what I've done with them has allowed easy examination of emissions, it's just the means in which you do the sniffing need be with characterized gear to know the readings will be close to accurate.
Member Fraser found a cheap source of near field probes, you should be able to find the thread with a search...yell if you can't.

These:
https://www.eevblog.com/forum/testgear/new-affordable-emc-probe-set-at-a-bargain-price-from-ariel-rocholl's-lab/

[nctnico]

Were there quite serious measurement errors with the siglent?

Yes, check the SSA3000 thread: https://www.eevblog.com/forum/testgear/siglent-ssa3000x-spectrum-analyzers/. I'm not a die hard RF engineer so I have to go by what a spectrum analyser tells me. Also the hackability may be stopped one day and then you are left with doing a hefty investment to get back to 3GHz.

[rhb]

I received a SSA3021X w/ "free tracking generator option" last Monday.  I have spent about 6 hours playing with it.  I have a very strong technical background, but no experience using an SA despite having had 2, one dead and the other flaky.  I bought this to avoid having to fix an SA in order to use it.

The Siglent hung today and required a reboot.  It would not respond to ANY button presses except power.  Not sure what the operation sequence was that triggered the problem.  I was quite unnerved.

If I set it up to span 88-107 MHz, set the center frequency to a station, set zero span and FM demod it works.  If I simply set center frequency, zero span and FM demod it sometimes appears from the screen to be demodulating properly, but the audio output is just noise. So far, the only way I've found to get it to work is set full span, reduce the span, then set the center frequency, zero span and FM demo in that order.  Changing the center frequency to tune to a different station may or may not work.  So damn poor operation relative to an RSP2 for 1/10th the price.

There is a maddening tendency for it to reset things not shown as a side effect of setting some other parameter.  As a new user I don't yet know if it's a bug or user error.

The unit has trial keys for all the options, but they time out based on operating time of the unit, not the option.  So I lost 6 of the 48 hours of use provided because I left it running on my bench while I did some household chores with it sitting on the default start up settings with a 50 ohm terminator on the input.

The root login has not changed, but the firmware is 1.2.8.2, so I presume that the "hack' does not work.  I don't care to try.  My interest is self maintenance.  An email to Siglent seeking a service manual produced the response that it was not finished but would be made available when it was finished.  For a product that's been on the market for a couple of years that's a very uncomfortable answer.

A number of searches failed to locate the source code for the GPLed parts of the firmware.

The USB cable supplied lacked an RF choke.  I'm using a cable I had instead.  In view of the intended uses of the product I found the supplied cable pretty dubious.

The user manual is not very helpful.  I've largely been mashing buttons and seeing what happens.  I understand SA design fairly well, so I think I have reasonable expectations.  However, I have found that the sweep speed is a lot slower than I'd expected.  But without experience with an HP I have no idea whether my expectations are reasonable or not.

[Joel_l]

I also thought I had an issue with demodulation on the SSA. The only way to get uninterrupted audio is to use full scan. Otherwise, you will get skips in the audio. It can be reduces somewhat by adjusting the demod time.

I suggest you go through the SSA300x thread, - already mentioned above.
https://www.eevblog.com/forum/testgear/siglent-ssa3000x-spectrum-analyzers/

and the hack thread ( yes it still works and there is a simple mod )
https://www.eevblog.com/forum/testgear/hack-of-sigllent-spectrum-analyzer-ssa3021x/

I have been happy with mine and most issues I ran into were user error.

[rhb]

The unit manifested behavior that suggests a HW fault.  So it is on the way back to the seller for evaluation.

I am very familiar with those threads.  The "hack" is foolish, but being able to log in via telnet is useful.  I strongly suspect that the SSA3021X is in most cases an SSA3032X that did not pass QC in the 2.1-3,2 GHz range.  If you look at the Rigol DSA line, the DSA832E is a down spec DSA832 for $1000USD less.  I've never seen anyone do a calibration test on a hacked unit.  I very much suspect that it's like CPU chips.  Same design and silicon.  Sort by performance and price appropriately.

[nctnico]

IMHO it is an urban myth devices are sorted like that because one way or the other you end up with selling better devices for a lower price or need to make a lot more devices and throw the lesser ones away. Both leads to excessive losses and waste. Better make one unit and configure it. You must not forget that a device consisting of multiple chips which needs to meet a certain specification has very low odds that the better chips all end up in a single device.

[Joel_l]

Scopes do this a lot. Take the RTB2K, base unit is 70MHz, you pay for a license key to make go up to 300MHz. No recal, fully supported by R&S. Others do this also.