Sub-80$ (USB) oscilloscope

[rstofer]

I get your point, and if I could get a 350MHz analog for this price I wouldn't hesitate. But why would I choose a 25MHz used analog over a 25MHz brand-new USB oscilloscope (apart from looking better )? The Owon seems to be better than the usual DSOs in this price range, and it seems to be pretty stable:

You wouldn't!

I don't know anything about the Owon USB scopes but I didn't see one that is sub $80.  Still, $105 isn't bad for a 25 MHz scope.

[vk6zgo]

I get your point, and if I could get a 350MHz analog for this price I wouldn't hesitate. But why would I choose a 25MHz used analog over a 25MHz brand-new USB oscilloscope (apart from looking better )? The Owon seems to be better than the usual DSOs in this price range, and it seems to be pretty stable: youtube.com/watch?v=gGOZ9PCVV_A
(Could someone tell me how to disable the Youtube video insertion?...  )

One thing:- A 25MHz Analog Oscilloscope is just that,no matter what the time/div setting.

DSOs  reduce their sampling rate when they are trying to look at long time intervals (20ms or so),because they lack memory depth.

In DSOs of the DS 1054Z class & above,this is not a problem,as the reduction is usually not enough to cause "aliasing",but with very old or very cheap DSOs this is a real problem if you need to look at  complex signals at such timebase settings.

A classic test,which we used to disconcert the Tek & HP reps back in the day,is to try to look at a PAL video signal at
field rate (50Hz).

This signal contains content up to 5MHz,which the early DSOs could not reproduce at long time/div settings due to their reduced sample rate at such settings .

Some of them even had trouble with video at line rate (15.625 kHz),with the colour burst signal at 4.433MHz reproduced as a bit of a "wiggle",having no relationship to the correct burst shape.

The cheap DSOs have the same problem due to cost concerns.
I've seen screenshots proudly posted on the internet  by someone showing off the performance of the latest "el cheapo" DSO,which exhibit this behaviour.

That said,no,I would not pay 80USD for either of the analog 'scopes you linked to---this equates to about $A111,which is about twice what I would pay for what are fairly unsophisticated instruments,lacking delayed timebase & other refinements.

If you could pick up a Tek,HP,or Philips with those facilities for 80USD,I would recommend you do so.
On the other hand if you are certain you will never need to look at high frequency signals using a slow timebase speed,then go for the USB 'scope.
If you are not so sure,get an analog,or save up for a Rigol or Siglent bench DSO.

[Godot]

Thank you all for the help. At the end, I decided to buy the Owon VDS1022 USB oscilloscope. (72€ on ebay, pretty good price ) I was thinking on what vk6zgo said, but I think I can live with it. When I will have to do such analysis, I plan to already have a decent oscilloscope 

[MrWolf]

If you are not so sure,get an analog,or save up for a Rigol or Siglent bench DSO.

To be more specific. You could only look at general shape of the signals in Rigol when zoomed in. And not do meaningful horizontal measurements but with cursors. So its a big question if 1.2kS screen buffer and large main memory or lets say 100k total buffer is better choice. I would probably also pick Owon  Gotta test it sometime.

[Gyro]

Not that it makes a major difference, but the buffer size on the VDS1022 is 5kS, every little helps.

[MrWolf]

every little helps.

5k not that bad. If 20ns div optimal for 5MHz, can still stay in game until 20us div. 3 orders. Line rate ok. Plenty for money.
BTW is there some other practical app besides video or some long digital transmission where would need to record at 20ms but analyze at 20ns?
Overall I like the concept as good "torture test" for scope.

[Godot]

BTW is there some other practical app besides video or some long digital transmission where would need to record at 20ms but analyze at 20ns?

I am also interested in this