Honestly, I have been eyeing the dos1102 as well.

I do a lot of basic electronics work, as well as repair old 80's era machines like Commodore, Tandy, and TI. For those I just use a cheap Hantek 6022BE digital USB scope, 20MHz more than enough for that kind of work. I just want something to use on things beyond 20MHz, but don't want to spend a ton on it, it won't get used a lot at first simply becasue I don't have that much room on my workbench. One nice thing about the 6022BE is it takes up no room. Whatever my new scope ends up being, once I have space for it, it will likely delegate the 6022BE to the tools bin as a backup.

All of that just to say, I would not mind opinions on the DOS1022 and others as well. 😀

Bear in mind you need 2x (some say 3x) the sampling rate of the operating frequency of whatever signal you're looking at. So 110mhz divided by 3 is 36mhz roughly. Which is plenty for really anything up until 1990 or thereabouts.

One guy on YouTube suggested a 4 channel model is better as r,g,b and I was a thing. But do you need to look at video signals simultaneously? The 1104 is USB powered, and those USB warts are noisy (per another video). I just want the 1102, but I do t want to short change myself.

oldhighgerman wrote on 2025-03-30, 18:56:

dos1102, 110mhz, 2 channel dos1104, 110mhz, 4 channel dos1202, 200mhz, 2 channel […]
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dos1102, 110mhz, 2 channel
dos1104, 110mhz, 4 channel
dos1202, 200mhz, 2 channel

For those of you that own scopes, by this make or any other, I'm curious of your thoughts. Basically the vast majority of the vintage stuff I intend to troubleshoot is in the single or double digit clocks. So really don't need more then the 1102. But 4 channels seems like it would be nice also. I suppose there isn't a lot of reason to go up to the 200mhz model, as this might be useful for very early Pentium stuff, but not much else. What day you?

In my oppinion, 4 channels is worth more than 200 MHz if you are at "single or double digit clocks" (I read that as 1MHz C64 to 50MHz 68040 / 80486 systems). Be aware that an analog bandwidth of 110MHz means that you will have a hard time judging the quality (i.e. rise time, fall time, overshoot) of a 50MHz clock signal. Symmetric distortions of a 50-percent duty cycle signals only result in odd harmonics, and you can't trust a 110MHz bandwidth digital scope to not have a steep digital filter attenuating 150MHz into oblivion, so every 50MHz clock looks (mostly) just like a sine wave. I suppose testing the signal quality of clock lines is not your main point of interest, so this limitation is likely not going to affect you.

As for channels, a lot of times a single channel is enough, but two channels are useful often enought that single-channel scopes are no longer a thing in anything but "toy level" scopes. Two channels is essential if you want to observe one signal in relation to another signal (like measuring setup or hold times). Three or four channels are not often required, but when you have a use case for a three channel measurement, not having 3 channels hits you harder than just having 110MHz bandwidth while probing a 90MHz clock (which will definitely appear at a lower amplitude than the signal actually has) still yields helpful information, so the is a gradual loss of measurement quality, not a full road block.

As use cases for three or four channels are not that common, going for the cheap 2-channel 110MHz model might still be good enough for you, though. Whether you pay the additional luxury to be able to see more than 2 signals in relation to each other depends on the amount of money you want to spend on a scope. If you are constrained on money, the 2-channel model is likely good enough, but if you can easily afford 4 channels, the extra flexibility and increased diagnostic opportunities might make it worthwile - especially if the scope offers logic-analyzer like features like trigger patterns involving multiple channels.

I have the DOS1104 - 110MHz, 4ch

It's a decent device. There are some things in the ui that are slightly cumbersome and at least mine freezes the screen for like 300ms after every 5 seconds.
But considering the price (and i got it especially cheaply, got lucky on local auction), it's fine.

If there's anything specific i should check or test for you, i can power it up and check it.

I've been eying ZOYI ZT-703S. A little handheld 2ch scope. If you don't go full professional, that might actually be a better fit... (And Adrian from the basement uses it a lot very successfully 😀 )

I've been fairly active in various fields of electronics since the 70s,
and have had *many* scopes over the years (starting with one I built ..
vacume tubes / 3KP1 scope display tube - everyone else in my tech class
was making radios 😀

These included some really big "boat anchors" (had to keep them on
scope carts just so I could move them around)!

FWIW: In recent years, I've been downsizing and ultimately decided to keep these:
(decided didn't need really fast, as I'm pretty much mostly interested in
"old stuff" now)

1Techtronix TDS-210 2ch 60mz (had for years, always reliable/accurate)
2Rigol DS1054Z 4ch 50mz (sometimes I really want 4-channels)
3Owon VDS-1022I 2ch 25mz (VERY portable unlike most USB is "real scope" inside)
4UNI-T UT81B 1ch 8mz scopemeter

the hanmatek junk is just rebadged owon that doenst pass owon's low quality bar (ive heard its like owon bstock). I'm not a big fan but its ok for basic stuff.

its ui is terrible and a massive lack of buttons, means LOTS of menu diving to do basic stuff.

also if your going 4 channels, you really want individual controls for each channel, makes the workflow much easier. 1 set of controls for 4 channels is real pain in the backside.

I had also considered something like the ZOYI ZT-703S as a replacement for the 6020BE simply because it takes up even less space, portable, and a little higher bandwidth (and based on Adrian's results with it). I just haven't pulled the trigger on one becasue my old 6022BE still works fine for most of the tasks I need it for. If I'm going to spend the money, I want to get something that's going to expand my measuring capability the most, within budget.

I would not mind having the dos1202 just to push it to 200MHz and widen my capability a bit more. I guess time will tell and I'll see what's in my budget when I finally go to make the purchase. At the end of the day, it's going to come down to what I can afford vs what I'm going to use it for the most.

Buying something "higher-end" would be nice, just to have it, but not for my use and budget needs. A vast majority of my uses are just to point me in the general direction of a problem to fix.

BloodyCactus wrote on 2025-03-30, 20:23:

... just rebadged owon that doenst pass owon's low quality bar ...

I bought the OWON VDS-1022I on a bit a whim... and was fairly impressed.

I was trying a bunch of USB scopes - and found that almost all of them were just high-speed data capture
devices, and relied on the PC for triggering, storage and other "scope" functions.. Not reliable at all if the
PC has some background stuff happening or for any other reason doesn't respond instantly..
This is usually "given away" with claims of "megs" of storage capacity.

The VDS-1022 was different (and not like some other USB scopes I looked at from Owon) .. It was
a "real" scope, with built-in triggering, storage etc... IIRC it has only 8K of storage capacity
- which is all internal. It triggers and captures reliably no matter how busy/slow the PC (in fact,
I most often use it with an Acer AspireONE netbook - tiny system with a slow Atom CPU - but
the scope works fine!

also if your going 4 channels, you really want individual controls for each channel...

Having individual controls is very important for your "daily driver" ... that's why I keep the Tek TDS...

I use it more than the DSZ because much more often than not I'm using <3 channels...

DSZ isn't what I would call "bad" - it has only one set of channel controls, in a separate block on the
front panel with 4 good sized buttons to select the channel to control ... and when I want 4-chan it's
well worth the huge effort of pressing the button for the channel I want to change if it's not already
lighted (selected)

I'm happy with the DSZ ... I got it very cheap, and didn't expect all that much from it,
as long a I could see the "rough state" of four channels at once it would have been "good
enough" for what I wanted it for - but it has proven to be surprisingly accurate and well
behaved!

People think bandwidth is the same as sampling rate. As it turns out, the mhz a scope has is a measure of its bandwidth, not it's sampling rate. They're 2 different things somehow.

Yep.. (much simplified) bandwidth is basally "how fast the input->A2D can transfer transitions",
sampling rate is "how often can you store the value read form the A2D".

It's not at all simple, because Nyquist says that you only have to sample at twice
the highest frequency - and people tend to think"sine waves" ... but if the waveform
is not a pure sine... the effective highest (Nyquist) frequency is/can-be MUCH higher.

eg: If you are trying to see a bit of random digital noise on a 10mhz sine wave,
you need a LOT more than a 10mhz scope... (and you really have to know the
characteristics of the "random noise" to be sure your equipment can catch it)

This is further complicated because many scope makers will quote bandwidth
and sampling rates based on sine waves - so you really have to know what you
are getting!

I also like HP scopes, favor them in fact. They just seem to be higher quality. I've used them many years ago when I was an EMI tech. In reality the places I worked at always seemed to have much more HP then Tektronix anything. And various other pieces of equipment, signal generators, spectrum analyzers, seemed more readily available from HP.

Yes I'm also perusing used scopes. Not that I even need 1. Have 3 (1 is busted, a low end 60mhz Tek).