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mvno_subscriber
March 3rd, 2017, 11:57 PM
I've been thinking about getting an oscilloscope for quite some time, as my trusty old multimeter can only tell me so much, and there are instances where it would be really nice to have a better visualization of what's going on. Obviously, scopes are not cheap - there are marked differences between the brands (and sometimes the retailers), and even though I try to read up on things it's not always easy to get a proper understanding of what the specs mean -- especially what they mean in my practical situation.

My wishlist is as follows:


Must be a standalone oscilloscope (i.e. no USB scope)
Should not take up too much desk space (I don't have a permanent workbench, so I need to be able to setup/take down fairly easily)
Screen resolution should somewhat hires (i.e. more than 320x240)
I prefer a responsive and intuitive user interface if possible




Bonus points if it has a function generator (for clock signals, etc)
Bonus points if it has/supports a logical analyzer
Bonus points for quiet operation
Firmware should preferrably receive updates


There are probably tons of other functions I'm not aware of, but these are the most important. I'll be using it mainly to diagnose my vintage computer equipment. My needs at the moment are perhaps modest, but I need a scope I can grow with - I hate to throw out and replace my tools. Budget is anywhere from $300-700 - of course I prefer to go low, but if it's a "killer" I know I'll regret not spending extra later. At these price ranges, I want it to last many years.


There are a ton of them on the market, apparently (and sadly difficult to find used oscilloscopes where I live), so I'm bound to have missed some good ones. However, my list of suspects are currently these:

KeySight EDUX1002A or G (http://www.keysight.com/en/pdx-2766404-pn-EDUX1002G/oscilloscope-50-mhz-2-analog-channels?nid=-32110.1203277)

Seems like low priced, great scopes
2x50Mhz, 1GS/s, 100kpt memory
Very new, can't find any reviews
G has 20Mhz function generator (I think that's the only difference), but priced about $200-250 higher


This one excites me, but not sure if the low price indicates I should be wary of something.


Tektronix TBS1072B-EDU (http://www.tek.com/datasheet/tbs1000b-edu-digital-storage-oscilloscope)


Known brand, "can't go wrong" they say
2x70Mhz, 1GS/s, 2.5kpt memory



Nothing much more it seems, but apparently a stable oscilloscope with the exception of the low memory. However, I have no idea whether it's actually sufficient or not



Rohde&Schwarz HM1002 (https://www.rohde-schwarz.com/au/product/hmo1002-productstartpage_63493-61541.html) (can get this used)


Apparently solid as hell
2x50Mhz, 1GS/s, 1Mpt memory
50Khz function generator
Logical analyzer, 8 ports (needs a $350 dongle though, but then I have the option)


This one makes me drool, but it seems the model was introduced in 2014 - does that mean it's old and I should go elsewhere? Also, the function generator is a bit slow.


UNI-T UTD4152C (http://www.hitech-egy.com/files/product663.pdf) (old model but being sold off with a discount)


2x150Mhz, 2GS/s, ?? memory
Logical Analyzer, 16 ports (included)


I'm not generally too keen on generic brands like this, and I got the feeling they overstated the specs a bit. It's also quite heavy. I included it here in case anyone had any experience with it, and it turned out not to be a turkey after all :)



Any opinions or tips to other models are greatly appreciated!

cthulhu
March 4th, 2017, 05:18 AM
Have you considered the Rigol scopes?

roberttx
March 4th, 2017, 05:33 AM
You can't go wrong with a Tek. That said, your list of requirements appears to be missing the bandwidth that you're looking for.

mvno_subscriber
March 4th, 2017, 05:50 AM
I have to admit I'm a bit confused regarding the bandwidth. Some say I need 10x what I'm measuring, others much less. I seriously doubt I'll measure anything higher than ISA (8Mhz), so I figured 50Mhz should do the trick?

mvno_subscriber
March 4th, 2017, 05:52 AM
Have you considered the Rigol scopes?

I don't know much about Rigol - if you have any pointers, I'd be delighted! I'm pretty green here.

Chuck(G)
March 4th, 2017, 07:36 AM
It depends upon what you're trying to do. If you're interested in the waveform of a repetitive event, a used analog scope can be economical with great bandwidth. Well-serviced used test gear can be a great bargain, especially for someone not living on the bleeding edge.

If you're trying to trace digital events, you will get more out of a logic analyzer.

There are multi-channel "hybrids" as well that perform some of the functions of both.

Here's an example of the difference: I was trying to deal with an SPI protocol bug where the slave device would suddenly quit responding after a few minutes of operation. A 'scope was useless for figuring out exactly what was happening, but I could program a logic analyzer (an old HP 1663A) to trigger on the hangup and show me what was happening before the event as well as what happened afterwards. Yes, it took longer to set up than a 'scope, but once that was done, I had the answer in 10 minutes (turned out to be glitch in one of the lines).

On the other hand, an LA would be useless for determining power supply issues or transmission line problems.

mvno_subscriber
March 4th, 2017, 07:44 AM
I'll be looking at both - power supplies/video signals, as well as analyzing what's sent on the bus. I don't currently do the last part, but I know that I'll need it sooner or later. However, it seems to me that a scope with a logic analyzer all-in-one is pretty expensive. I would of course prefer everything in one package, but it seems to me like I'll have to buy scope/analyzer/function gen separately. Unless some of you have any great tips, that is :)

eeguru
March 4th, 2017, 07:59 AM
My $.02. Do not go out of your way to acquire a scope with a multi-channel digital input LA (a 'MSO' scope). I've never come across a scope with digital analysis that was worth a damn. And they all charge excessive premiums for those inputs. You are better off using a dedicated logic analyzer for multiple input digital (both function and price).

That being said, you will probably want the software options for I2C, UART, SPI, CAN, etc (whatever you use) enabled so looking at an interface using the analog probes will decode the protocol while inspecting edge transitions and exact transition delays. LAs can't show you those things and it helps when a scope can give you best of both worlds.

Uniballer
March 4th, 2017, 08:07 AM
I have to admit I'm a bit confused regarding the bandwidth. Some say I need 10x what I'm measuring, others much less. I seriously doubt I'll measure anything higher than ISA (8Mhz), so I figured 50Mhz should do the trick?

A 50 MHz scope can do a good job on a 50 MHz sine wave. But a square wave consists of the fundamental plus the odd harmonics. You only get to the 5th harmonic of an 8 MHz signal on a 50 MHz scope (so square waves won't look very square), and you are probably going to have a tough time making sense of what you see because of the poor response to the fast rise/fall times. I would recommend at least a 100 MHz scope (that will get you to the 11th harmonic - good enough), and more if you can swing it.

Chuck(G)
March 4th, 2017, 08:32 AM
Okay, now we know what you need the 'scope for. Let's figure out how much you need.

A used analog scope can be economical and a good investment for a hobbyist. Consider that a professional engineer might use a scope every day of the week, where a hobbyist may only need to pull one out only every so often. Industrial test equipment is usually well-constructed and made to be serviced periodically. I have an old Tek 465A scope that must be somewhere around 40 years old and it's still going strong. You could most likely fill your needs with shopping for an off-lease or government/industrial surplus unit. Heck, I still know a few folks who swear by their old vacuum-tube 'scopes.

Don't get me wrong--a nice new DSO can be pretty flashy and very useful, but you don't buy a Maserati to drive the two blocks to the local supermarket. Or do you? :)

FWIW, what I've seen of Rigol scopes says that they're pretty decent at a lower price point than the Agilent/Keysight Tektronix new gear.

KC9UDX
March 4th, 2017, 09:38 AM
My old vacuum tube scope has considerably better than 320x240 resolution. :)

And it might be RoHS compliant, with its ceramic strip construction...

cthulhu
March 4th, 2017, 10:29 AM
FWIW, what I've seen of Rigol scopes says that they're pretty decent at a lower price point than the Agilent/Keysight Tektronix new gear.

Searching on YouTube for Rigol brings up some interesting reviews of their products. https://www.youtube.com/watch?v=ETCOhzU1O5A is a good one to watch.

gslick
March 4th, 2017, 11:42 AM
If you're considering buying an entry level scope new you can't go too wrong with the Rigol DS1054Z.

One of their selling points for hobbyists is the ability to unlock some of the optional features:
http://www.eevblog.com/forum/testgear/new-rigol-ds1054z-oscilloscope/

As far as the entry level scopes from Keysight and Tektronix go, I believe the brand new InfiniiVision 1000 X-Series would have some better features than the TBS1000B series. The InfiniiVision 1000 X-Series is based on the same MegaZoom IV ASIC used in the higher end InfiniiVision 3000 X-Series, but some of the features are crippled in firmware. If you wait a week or two there will probably be many full reviews of the InfiniiVision 1000 X-Series on YouTube.

Here is the EEVblog teardown video of the new 1000 X-Series. He's working on a full review video to post soon.
https://www.youtube.com/watch?v=9KcOQsVxtoU

For my own use I have a Keysight MSOX-3034A which is nice scope to use, and really more than I need.

mvno_subscriber
March 4th, 2017, 11:46 AM
Hehe, a friend of mine has a Maserati. He drives it once a year, then spends the rest of the time fixing what broke during that one ride ;)

I was out today looking at a used Agilent DSO3102A (link (http://www.keysight.com/en/pd-580288-pn-DSO3102A/oscilloscope-100-mhz?cc=US&lc=eng)), that's a 100Mhz scope. Anybody knows this? The model is about 10 years old I guess, the guy selling it didn't really want to give a price, so I'm left to suggest one - if this at all is an OK scope.

I wouldn't mind having a simple CRT scope, but it's either something really simple or something a bit more expensive (so either an old VW Beetle or a new Toyota - is that a better comparison? :))

Where I live, used scopes aren't easy to come by, at least not online. But I understand that investing anything "considerable" in something less than 100Mhz is not so wise, then.

gslick
March 4th, 2017, 12:20 PM
If you were looking at used older HP / Agilent scopes maybe something like a 54622A / 54622D would be better in many cases than the DSO3102A if you could find any of those in your area, unless the DSO3102A was really cheap. The 4K memory depth and 320 x 240 display of the DSO3102A doesn't seem that good.

To keep things retro, the 54622A / 54622D even use 3.5" floppies for storage. None of that fancy USB stuff. :)

mvno_subscriber
March 4th, 2017, 12:40 PM
Rigol DS1054Z seems really charming, but I can't find anyone selling that brand in my country. Basically, I'm limited to whatever is on farnell.com - there are other suppliers, but they are very good at having stale prices.

For now, the KeySight DSOX1102 A/G seems like the best bet, if it is the case that a 50Mhz scope wouldn't cut it. I would love to get some more opinion on that, because it has a _lot_ to say on the price (the EDU versions are considerably cheaper, but non-upgradeable).

I've got to whack my head and sleep on this.. (22:40 here) :o

Chuck(G)
March 4th, 2017, 01:05 PM
See here (http://www.rigol.eu/how-to-buy/):

Venotek AS
Hesthaugveien 24
5119 Ulset

Tel: +47 55197220
Fax.: +47 55192666
Email: post@venotek.no
http://www.venotek.no

g4ugm
March 5th, 2017, 01:02 AM
You might want to see what the nearest Hacker Space of FabLab has. The FabLab in Oslo appears to be in some sort of limbo..

https://www.fablabs.io/labs?country=no

and the list of HackSpaces is here:-

https://wiki.hackerspaces.org/norway

these places will usually have scopes you can try. To be honest for most vintage work I use a cheapo USB Scope. I also have an expensive USB scope but it tends to stay safely in its box....
... and Rigol had a stand at the UK National HamFest so they are obviously into direct supply to amateur radio market. Note they have now locked down the firmware so illicit upgrades are no longer easy...

mvno_subscriber
March 7th, 2017, 08:06 AM
Closing in on a decision here.. In the meantime, I found this article by Rigol which explains in a simple manner why you would need a sample rate so much higher than what you're measuring (especially when dealing with digital signals):

https://rigol.desk.com/customer/en/portal/articles/2268981-why-does-my-scope-show-a-sine-wave-when-i-expect-a-square-wave-

Chuck(G)
March 7th, 2017, 08:20 AM
Yes, that's something that a user of DSO needs to be aware of--you can get wildly unexpected results if you don't understand the fundamentals.

Closely related to a Scandinavian personality, Harry Nyquist: Nyquist rate (https://en.wikipedia.org/wiki/Nyquist_rate).

Sorry, not Norwegian, but close. :)

Formal description is the Nyquist-Shannon sampling theorem (https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem), named after Harry and Claude, but developed by a Russian Vladimir Kotelnikov. (https://en.wikipedia.org/wiki/Vladimir_Kotelnikov)

This is why many old-school engineers prefer analog 'scopes--you may get bandwidth-limitation effects, but those are much easier to predict than under-sampling effects. The downside is that most analog scopes have no memory--for single-event phenomena, the best one can do is a 'scope with a special storage tube. They can be a pain to operate and use.

KC9UDX
March 7th, 2017, 12:05 PM
For years, I've been meaning to ask the community here (maybe I even, did, and don't remember!) "What happened to all the storage tubes?" I haven't seen a terminal with one in over thirty years.

By the way, it's pronounced "nick-VIZT" :D

If one has never used a storage scope, one never needs one, in my opinion. I used to adjust Mitsubishi PLGs with a cheap 30MHz time-delay triggered scope, something most experts say can't be done without a modern digital storage scope.

As a matter of principal, I will always buy an old Tek over a new Rigol, for this one silly reason: The difference between them is a fine example of everything that is wrong with the modem world. Tektronix used to be the absolute highest quality, better than anything else money can buy. Rigol is just quick, dirty, and cheap, especially CHEAP, because that's the most important attribute of products these days.

Chuck(G)
March 7th, 2017, 12:43 PM
Well, sure--I've seen the same thing across the board. For example, I needed a new effluent pump; at first I thought I'd stay with my old standby, Zoeller. Then I read the reviews on Amazon and discovered that, as of 2013 the new pumps bearing the same model number, were absolute garbage--and Zoeller had dropped the 3 year warranty on them to 1 year. (I ended up buying a Duramac; I hope that I'm not disappointed)

The driving force is that, as technology advances, the requirement that a piece of test equipment to put in a 25 year service life has largely gone by the wayside. So, they're made cheaply because they're not expected to last very long.

KC9UDX
March 7th, 2017, 01:28 PM
I've been down that same road with effluent and sewage pumps.

I eventually stopped buying the industrial brands with the quality reputations and went to Menards and bought some Coleman brand ones (actually claiming to be made in the USA). If your Duramac does what my Coleman pumps have been doing for 7 years, you'll be happy.

SpidersWeb
March 7th, 2017, 02:03 PM
I bought a Rigol DS1054Z, prehacked by our friends in China - so that's 100Mhz 4 channels, 1Gs/s, large colour gradient display, and came with four 300Mhz probes, I2C, RS232 decoding etc, can save waveforms to USB - for a price that wasn't unaffordable for a hobbyist. Was perfect for my needs (and finding second hand scopes here that are actually a reasonable price is infuriatingly painful if you don't know people who know people).

But I understand the point about quality being flushed for cost reduction. Often just to save a few cents per unit. We bought a 55" LG Smart TV, and after two years it gave up on us.
Thankfully NZ consumer law allows us to return things even after the warranty has expired in that situation. So thanks for the new TV LG, next time don't build rubbish.

roberttx
March 7th, 2017, 03:09 PM
As a matter of principal, I will always buy an old Tek over a new Rigol, for this one silly reason: The difference between them is a fine example of everything that is wrong with the modem world. Tektronix used to be the absolute highest quality, better than anything else money can buy. Rigol is just quick, dirty, and cheap, especially CHEAP, because that's the most important attribute of products these days.

My first scope was a B+K, with a whopping 20MHz bandwidth, but I quickly moved on to Teks. I think there's four full sized ones in my workshop right now, but the fastest is only 150MHz. One - a nice four channel job on a cart, has what I think may be PSU issues. It will cycle through POST 2 to 4 times before coming up, then will randomly reboot itself while in operation.

Interesting Tek story. When they started, they used to buy CRTs from RCA and DuMont. Apparently there were tensions, because both those companies also sold 'scopes - one book asserts that DuMont even went as far as shipping substandard CRTs to Tek and I think I once saw the same said about RCA, but don't recall the source. This led to Tek setting up their own CRT plant and, eventually, driving the others out of the O'scope market.

Agent Orange
March 7th, 2017, 03:28 PM
one book asserts that DuMont even went as far as shipping substandard CRTs to Tek and I think I once saw the same said about RCA . . .

There may be some truth to that. Way back when, I worked for Raytheon in a cal lab which did Navy contract work. Tek was the de facto scope during that era for the Navy's repair facilities. However, when it came to storage scopes, it was always HP.

KC9UDX
March 7th, 2017, 03:50 PM
Interestingly, I have a very nice Navy scope, which was made by Dumont.

I wonder if I can find a manufacturers mark on the tube in the Tekteonix 310A that I have.

Agent Orange
March 7th, 2017, 04:21 PM
Interestingly, I have a very nice Navy scope, which was made by Dumont.

I wonder if I can find a manufacturers mark on the tube in the Tekteonix 310A that I have.

I know they existed, but I don't remember anything DuMont except maybe the old tv network. Does it have a milspec on it. Even an outfit like Monsanto made freq counters and such under a milspec.

KC9UDX
March 7th, 2017, 06:14 PM
I know they existed, but I don't remember anything DuMont except maybe the old tv network. Does it have a milspec on it. Even an outfit like Monsanto made freq counters and such under a milspec.

Yes, I'd have to dig it out to read it. It has all kinds of official labelling.

mvno_subscriber
March 9th, 2017, 12:53 AM
Oh dear, I guess I'm disappointing everyone now..

KC9UDX: Sorry, I agree with your statement regarding spending the extra for quality, but these are costly items for a hobbyist. However, the manufacturer seems to have proven itself to be good and stable, and I have to start somewhere don't I?

Chuck(G): No Maserati, but close enough..


I've just ordered a Rigol MSO1104Z - got the MSO option for less than $100 extra plus a free Rigol carrying bag. I also got it from my own country (Norway), which means 5 years warranty by law. I'll have to wait a few weeks before it arrives, but boy am I looking forward to it :P

Tor
March 9th, 2017, 02:29 AM
I also got it from my own country (Norway),Where's the best place to buy a Rigol in Norway, if you don't mind?

KC9UDX
March 9th, 2017, 05:14 AM
5 year mandatory warranty! As much as I hate specific legislation, that might solve our China quality problem if more places did that.

gslick
March 9th, 2017, 06:40 AM
Back to the new low end but still not extremely cheap Keysight InfiniiVision 1000 X-Series, maybe breaking out a soldering iron and changing some ID resister values will get you a 200MHz capable scope for the price of a 70MHz scope. Of course that voids the warranty and most people might not be comfortable doing something like that. These are new enough (just released the beginning of March) that the full details are still being investigated...

https://www.youtube.com/watch?v=YC6JCVHk80c
http://www.eevblog.com/forum/blog/eevblog-978-keysight-1000x-hacking/

mvno_subscriber
March 9th, 2017, 09:59 AM
Call me old school, but I prefer to buy my software (and also not voiding the warranty!). Some think having to pay for unlocking benefits in software is a bad thing, but I'd say it's an excellent way of subsidizing. The one's purchasing software updates you don't need help fund the low entry price, and even though it might be rather easy to hack, I would argue it's uneconomical in the long run.

Tor: http://www.venotek.no - as given to me by Chuck(G) (thanks a bunch!!). Looks like they're the only authorized Rigol dealer in Norway.

gslick
March 9th, 2017, 12:50 PM
Yeah, I paid for my MSOX3034A and the full set of feature licenses instead of buying a lower end model and trying to do any sort of upgrade hack. I wasn't interested in doing that. I paid a fair amount below the full list price and I wouldn't have paid that, but it was a legitimate Keysight offer at the time, probably because the 3000T models were just about to be announced.

Chuck(G)
March 9th, 2017, 01:21 PM
For the ultimate in low-cost o-scopes, I ran across one the other day that used the $4 "Blue Pill" STM32F1 boards. USB connection to a PC for display and control. I think it topped out at 100KHz. I doubt that one could get to be much cheaper.

KC9UDX
March 9th, 2017, 03:36 PM
Except that the low cost assumes that the buyer already owns a suitable PC.

I remember when we didn't need USB; we used the Soundblaster joystick port for direct sampling.

Tor
March 9th, 2017, 11:06 PM
Those Rigols always looked interesting, and I still may get one - but last year I got an old 100MHz DSO for free, w/storage and a built-in printer. Works perfectly fine, but it takes forever to boot.. not what I'm used to with the HP and Tek scopes I used in the past!

Thanks for the venotek link - unfortunately it's one of those shops which won't show the price, instead you have to ask for a quote. I always stay from that kind of business, I despise it.

mvno_subscriber
March 10th, 2017, 01:06 AM
I actually asked them about that. They have prices on a lot of stuff except Rigol. The reason why is because they normally don't stock them, and the price they sell for varies depending on the currency rates (especially now with NOK being so low).


Personally I kind of like it, because when you know the going rate it's easier to get a good deal. A lot better than shopping online :)

Tor
March 10th, 2017, 01:45 AM
I actually asked them about that. They have prices on a lot of stuff except Rigol. The reason why is because they normally don't stock them, and the price they sell for varies depending on the currency rates [..]) I see. That makes some sense. Personally I find that I won't ask for a quote if I don't even know the ballpark of the price to begin with, and I think that's something that will cost them a bit - I'm not alone in feeling this way.

gslick
March 15th, 2017, 04:19 PM
If someone is looking at 4 channel scopes that are in the 2000 class level (a step up from the 1000 class entry level, most vendors seem to have similar number schemes now) Rohde & Schwarz just announced their RTB2000 series. I haven't seen any full reviews of them yet. Bloggers are just getting them now.

The interesting thing is that they appear to have an launch edition deal where you can get a fully optioned out 4 channel, 300MHz + 16 digital channel RTB2004 for $2000 instead of the regular list price of close to $6000.

A lot more scope than is really necessary for vintage computer work, but if you do have a need for that level of scope, or just have the budget and want one, it might be interesting to take a look. If nothing else more players in the scope market is always good for driving prices down.

https://www.testequity.com/products/33440/?pitem=45772#tabgroup
Rohde & Schwarz RTB2K-COM4.99 RTB Complete Oscilloscope
Launch Edition Promo Includes Options Worth $5,865!
300 MHz, 4-ch + 16 ch MSO, 10bit, 10 MSa, 10" WXGA Touchscreen, Waveform/Pattern Generator, 12C/SPI/RS232/UART/CAN/LIN Trigger/Decode, History/Segmented with 160MSa of memory. (RTB plus: RTB-B234, B1, B6, K1, K2, K3. K15) (1333.1005P99)