I got the scope recently, needed something portable to find why my car did not want to run.
In my use case I found 2 areas lacking:
1)If you use a wide time band (ex. 100ms per division) it will miss a lot of data. Theoretically it could capture the data (with a supposed 1GSa/s) , but seems like the limitation is in the sample memory (supposedly 240 Kbit). When the trigger hits, the oscilloscope captures 30 time divisions. With one sample supposedly 8 bits, you get 30K samples over 30 divisions, so 1K samples per division. But I really doubt it's 1K samples per division, and I am a beginner with oscilloscopes so not sure if I have correct assumptions. So if you don't know what the frequency of the signal will be, you might miss some important details if you use too wide of a time division.
2) The trigger behavior seems odd. I used a Rigol DS5102CA before, and the trigger was intuitive. With the FNIRSI it seems odd and I didn't use it enough to say what is wrong, but it feels like it's not a good implementation.
What I chose to buy it:
In my area you can't find a good oscilloscope for a decent price. I needed a portable scope, and with all the drawbacks this one is the best option.
If I would be in the North America I would get the Rigol DHO802 for 330$ and not waste my money on the FNIRSI. But I am in eastern europe and the DHO802 is 415 euro, and I have to also add 20% customs VAT (and potentially shipping), so that makes it 500+ euro. So the 130 euro FNIRSI it is.
It's not something you can confidently use if you need it for serious/responsible work (at least that is my opinion), but for a lot of use cases it gets the job done.
Are you sure about that? that 1Gs/s is the real sampling?!
Based on tests, the oscilloscope corresponds to a maximum of 30 Mhz.
I tried what you wrote with the 1013D with its factory firmware.
I gave it a 51Khz square signal, with a 100ms time base, then stopped it, then tried to zoom in on it, but it wouldn't let me.
When I set the trigger to Single, the time base was automatically set to 10mS.
I don't know what other people's experience with this device is, but I don't think it will be suitable for what you want.
I quickly tested it with my Micsig.
I can't upload a picture now because I have to go to work, maybe tomorrow if you're interested.
I gave a 51Khz square signal to both.
My Micsig memory is limited to 28k.
The time base is 10ms, because only then does Fnirsi allow me to zoom in on the stopped wave.
The difference between the two waves is heaven and earth.
On my Micsig, the whole wave is continuous, and I have to zoom in even more to see the waveform.
Fnirsin is worthless in comparison.
So does Fnirsi use much less memory?
Maybe you would be better off with a Hantek 1112. Although there are many complaints about that.