Hi Dan,
I'll admit that I've been spoiled rotten for DSOs, I've owned a LeCroy 9310M for many years now. I bought it second hand, it was expensive even then, but it's paid for itself so many times it owes me nothing. It is getting a bit long in the tooth and parts are harder to get now. So I thought I check out what was on the lower cost market a couple of years ago.
I went through the low cost DSO market, sending an email of questions to each manufacturer. Hantek looked ok, I arranged to see one in use before buying and on the surface it looked ok. It was a little different in the way it handled memory and sample rate, but different is ok. The manufacturer was very poor at answering questions, they actually accused me of being a competitor trying to get their "proprietary secrets". I had just asked them the same stuff you can read in any LeCroy user manual, nothing exotic, but I should have been alarmed by their attitude, but I liked the colour screen - it was a bad mistake. I bought a Hantek DS5102B. I've done the usual software upgrades, but nothing really works. I can't trust what it says on the screen, it locks up and needs rebooting a dozen times a day. That's not an exaggeration. When you try to get it to do anything much, it crashes. Remember, I'm used to a 20 year old LeCroy scope that hasn't crashed on me ever. Truly, not once, ever.
The Hantek is junk, I'd love to get it out of my sight, it reminds of how I stupidly let a shiny display beguile me into wasting money. However, in conscience, I can't sell it, it's rubbish and I'd only be giving some other less experience person a headache.
So, I liked the neat colour display, I liked the small size. The Rigol DS2072A had just come onto the market. I researched, thought it was a fair chance and bought one. I'd be happy to on-sell this one though, because it works reasonably well, but I don't really want to keep it. It just doesn't appeal very much. It does some good things, but it's hasn't got the raw horsepower that a LeCroy has, even one 20 years older...
I've used the Rigol for a while, but also asked Rigol about how their scope worked. They were polite, but coy about display compression algorithms and whether their scope had one. For example, you've got a 100k single shot acquisition. How does the Rigol scope write this onto a display with only 800 horizontal pixels? Rigol won't tell me. If you look up the LeCroy user manual , it explains how the display compression algorithm works, they break the contiguous acquisition into 400 bins, pick out min and max values, then write each one onto the display giving 800 pixels, but showing any amplitude deviations, even as small as one pixel wide. If you see it on a non-zoomed display, you know there is a problem to be investigated, and use the zoom mode to check out the precise nature of the spike that was shown. Why is that so difficult? Well, it's a lot of data processing, and to do it fast enough to retain a reasonable update rate, it has to be done in hardware, and that's how LeCroy do it. I can trust that. I've checked that even a single pixel out of place shows up exactly as they promise, and it does.
Summary: The Rigol is ok, the small bench footprint is useful, but I still don't really trust it for anything except preliminary investigation. The Hantek is a complete waste of bench space, money, time and effort. The hardware looks like it should be ok. The software is amateurish, and their support is laughable - or it would be funny if I hadn't actually paid for it. Another spec that really matters for DSOs is equivalent bits. At high speed, most DSOs lose bits of acquisition due to errors, jitter and noise. So a fast acquisition is probably only 6.8 equivalent bits, and LeCroy's handbook will tell you exactly what you get at full speed. None of the other manufacturers will admit what their equivalent bits at speed are. That's what I mean about trusting a scope's results.
In the end, I bought a new old LeCroy, despite having a huge case, being very heavy and having a loud fan, and expensive, but it has a colour display and is totally trustworthy. If it passes it's boot up calibration routines, you know it's in spec and good. You can access the AtoD calibration results from the maintenance screens with LeCroy. You know, if you connect the 1kHz calibration output to a 50 ohm coax cable, then to a BNC T on one input and hang a half metre piece of coax cable on the spare end of the T. Set the input to 50 ohms, and look at the pulse reflection on the cable, and you can measure how many centimetres of cable you have attached to the input. Light travels about 20cm in a nanosecond (in a cable) and it's easy to measure 50cm of unterminated cable with the LeCroy. Try that with the Hantek...
Cheers, Colin
Melbourne
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Or, given I have version hw0 hardware should I just cut my losses and trade up for something newer/better and stop wasting time on this one?
Thanks,
Dan
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