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I don't see how you can call this expected behavior. The scope is supposed to display the next second after the first rising edge, but it does not show the second pulse at all. I think the 10Hz spec is only for "AC coupling", but I am using "DC coupling". By the way, my other oscope shows both pulses correctly, both in "rolling mode" and "single-pulse mode".

@@bobuhi I notice with my own mushers, Fnirsi 1013d, fnirsi DHO108H, Fnirsi 2c53p, Owon HDS272s v3, Zoyi 703, and sigpeak, that it does not trigger the fast edge well in slow time base, and sometimes it misses. It could also be that you missed the first pulse and triggered the second one. I think this is due to low memory and slow sampling. As far as I know, AC/DC coupling only means connecting a capacitor in series with the input, through which the signal blocks the DC components. It has nothing to do with the trigger. After I go home from my work I will test, and try to figure out why

One more thing. The video only shows 250ms and 500ms pulse separation, but I also looked off-video between these two limits (like 450ms). The oscope then truncated the second pulse right at the half-way time point. In other words, two pulses show on the oscope, but the second pulse was shorter than reality, so this truly is buggy unexpected behavior where the right half of the screen just gets zeroed. I didn't get those tests on video because I control the pulsing with the same camera phone that took the video.

@@bobuhi I had some time to deal with it. I noticed that the retrigger time at 100ms is approx. 4 seconds. If the next pulse is within this, it will only trigger on the second pulse, it will not see the first. This could be a setup error or a physical limitation of this scope. If you use a normal trigger and bombard it with e.g. 1, 2, 3 Hz pulses, you will see the time elapsed between the two triggers. Do not think that the wave outside the screen is real, it is possible that it is some kind of memory garbage. I tried to find out, if I sweep a signal, what is the width of the memory at 100ms/Div, that is, how many seconds. The result was always different. Unfortunately, you can rotate all the data in the memory as many times as you want, it is not limited like with an Owon. There, if you reach the end or the beginning of the memory, it stops. It has a display bug where part of the wave looks narrower, but when I zoom in on it, the width is fine. At least that's how it worked for me. I understand that it's fine for you on other scopes, it's the same for me, it's fine on my larger scopes and Owons as well. But not on the Fnirsi and this ZT-703. Here, re-triggering takes time and sometimes it misses you. I tried with a faster time base and with pulses, I wanted to capture the start of my signal generator with a single trigger, and I noticed that it did not trigger on the first pulse, but even on the 5th pulse. I also wrote that you should try it so that the trigger time is in the middle. or at least set it so that the two pulses fit on the display even if it triggers the second one. I don't consider this a software bug because I've seen it on several smaller scopes, even with Owon, which is not a low-end one.

Yes, my location is known for radon, and I've tested the radon multiple times with results ranging from 1 to 4 pCi/L. I'm sure a strong enough cosmic ray could ionize my room's air also, but that level/type of cosmic radiation is not normal (if a cosmic ray did this in my room, it would have left an ion stream along its entire path through the atmosphere to get here, and I would bet the required power from space then gets far larger than we normally observe).