Oscilloscope Recommendation? - Page 1
Forum section: electronics / testgear

author: loneoceans
author_rank: Contributor
timestamp: June 18, 2014, 04:55:16 pm
content: Hi everyone,I'm looking to buy a scope that will last me a while. I have some background in electronics, and have been using scopes on an off over the course of several years. However, I've mostly just been using whatever scope that is around in my lab / workshop, but would really like to have one I could use at home. My budget is around 600 or so. I know there are some nice options in the 800-1000$ range, but I think that's really a bit beyond my budget.I was initially thinking of the $399 RigolDS1102E100Mhz (or the 50Mhz version) which seems to have had great reviews everywhere. However, I've sometimes had the need to do quick differential measurements, which made me think that a 4 channel input might be useful. This brings me to the RigolDS1074Z70 MHz, which seems to be a newer scope with a really nice screen, all for $585.What do you folks think about these or have any other recommendations? I've been reading that the low end teks are not all that impressive. How about Siglent scopes of this price range? Finally, I hear there may be a hack for both Rigol scopes - it's not really a priority but always nice to haveOne last thing - do these scopes accept dual mains input (i.e. 120V and 240V?)Last question - if I decide to buy a Rigol, any ideas where's the best place to buy it? From testgear? Rigol directly?Thanks everyone!

author: davorin
author_rank: Unknown
timestamp: June 18, 2014, 06:30:48 pm
content: I would definitively also have a look on ebay....Bought a long time ago a used LeCory 9354AL, and I am still happy with it...I also considered back then some new DSOs with either 2 or 4 channels....but most of them had too little bandwidth for my taste...Of course it depends what kind of electronics you would need it for....but nowadays processors systems are running at several 100s MHz...not few MHz as 10 years ago (o;One great plus of older but still perfect DSOs are the fact that you get all the service manuals and many times you could do the repair by your self....

author: tautech
author_rank: Super Contributor
timestamp: June 18, 2014, 09:59:51 pm
content: Welcome to the forum.For a local recommendation you need to set your country in your profile.4 Ch for differential measurements is a wise plan.DSO's with all their additional functions over CRT scopes is a good choice.Most DSO,s can handle 100 to 240VAC, 50 to 440 Hz, but check before you leap.Siglent SDS1074CFL is 4 Ch, 2Gs/s sampling and 7" screen for RRP US$793 + taxes if any

author: loneoceans
author_rank: Contributor
timestamp: June 18, 2014, 11:11:48 pm
content: Thanks tautech. I'm in the US; would be great to have a scope that I can get here without too much difficulty. I've used both before but I think I really would appreciate a nice lunchbox scope I can carry around instead of having a big heavy CRT.Thanks for the Siglent recommendation, but that's really starting to push my budget a bit too much. I guess the general consensus is that the Rigol's are pretty decent? Any other scopes worth considering which are similar to the DS1074Z?Finally, browsing more threads here, it does seems like the 1074z comes up highly. If so, any suggests were to best buy it in the US? Amazon doesn't seem to stock it.

author: Stephen Durr
author_rank: Contributor
timestamp: June 19, 2014, 04:35:46 am
content: One good distributor in the US is TEquipment.NET, there is a link to their site on the eevblog.com main page. I think eevblog members get a 6% discount, you can call them for the discount code or pm user tequipment on this forum.

author: loneoceans
author_rank: Contributor
timestamp: June 19, 2014, 04:41:24 pm
content: I know there's a great sticky on Multimeters - is there one for scopes too?Anyway the rigol sounds great! Thanks everyone and Stephen Durr for the heads up!

author: tequipment
author_rank: Regular Contributor
timestamp: June 20, 2014, 05:00:23 pm
content: Just send me a message if you need our code.ThanksEvanTEquipment.NET

author: David Hess
author_rank: Super Contributor
timestamp: June 21, 2014, 05:32:06 pm
content: I have had good results using add and invert mode to make differential measurements but be aware that differential measurements using add and invert mode have a limited common mode range which severely limits sensitivity. Analog oscilloscopes and some early DSOs do a little better here because the addition is done earlier in the vertical signal chain. For measurements with high common voltages, a real differential input is needed.If buying a new DSO, I would definitely exclude those that lack a graded index display.

author: Andy2
author_rank: Contributor
timestamp: June 21, 2014, 08:58:53 pm
content: Hello everyone. I'm new here so please be gentle with me as I suspect I may be about to say something dreadful.Analogue scopes shouldn't be ignored, they can still do stuff that (in my experience) DSO's cannot do well, or in some cases cannot do at all. After years of using analogue scopes at work and at home (I'm a radio amateur who likes to build stuff), I decided to replace my ailing Tek 2445 with a shiny new DSO. I think it was the Hantek 5202 (200MHz, 1Gs) and it worked really nicely at audio and low radio frequencies up to around 20 MHz. I was really impressed by the crisp, stable display and prepared myself to enter a new age.Then I tried setting up an AM transmitter (low power, about 0dBm) on 50 MHz. Ooops. The darned thing refused to show me the familiar 'envelope' waveform, it just filled the screen with mush, no matter how I tried to set it up. It was like it couldn't decide what to trigger on or what speed to run the timebase at, it was really upset! On a simple unmodulated signal it was fine, but on a modulated carrier it would not co-operate.I heaved the old faithful Tek back onto the bench and all was sweetness and light again. The Hantek went back and I re-instated the Tek. Are they all like this or is it a limitation of the sub £500 market? A friend of mine who works at a lab tells me all the old techies there keep their old analogues in the cupboards as a backup 'because the new £££££££ digital ones the management insisted on buying tell lies'.

author: David Hess
author_rank: Super Contributor
timestamp: June 21, 2014, 09:11:47 pm
content: AM modulation and video are among those cases where a graded index display is really necessary unless you just want to view the envelope. As far as I can tell, your Hantek 5202 lacks this.The 2230 DSO I used most often also lacks a graded index display but since it is a combination analog and DSO, that is not a problem.On the other hand, your Hantek will certainly outperform your 2445 when looking at things like startup faults in switching power supplies and other low repetition rate signals.

author: Electronics-Repairman
author_rank: Contributor
timestamp: June 22, 2014, 07:39:35 am
content: I have Siglents sds1102 CNL , seems a fare oscilloscope, at a reasonable price, and as far as I understand , they make scopes for other companies.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: June 22, 2014, 07:53:21 am
content: Quote from: Andy2 on June 21, 2014, 08:58:53 pmthis is a complex issue, one That isn't a black and white issue. The particular area you mentioned is an area that only recently digital scopes started to become competent . Due to their digital nature, early digital scope either showed a pixel as on or off. There was no intensity gradient, only a stark yes or no. This intensity gradient is what you are used to seeing on your analog scope. A weak signal shows up as more dim. On older digital scopes, the weak signal intensity is the same as the strong signal intensity. Recent digital scopes like the Siglents and the Rigol DS2700 and DS1074 series have the intensity gradient function. These give that "third dimension" of measurement that you are missing in your Hantek(that I know of none of the Hantek scopes have this feature, someone correct me if I'm wrong ). These, combined with their long memories, should be able to give exactly what you are looking for.

author: Andy2
author_rank: Contributor
timestamp: June 22, 2014, 09:55:39 am
content: Many thanks. I bow to your greater knowledge, but I struggle to understand what the problem is!Surely at its most basic, a DSO is just an ADC and some hardware/software to plot the computed points on the screen? If my 50 MHz RF signal was varying relatively slowly (say by manually turning a knob) the scope would faithfully show the amplitude changes? So why can it not show the amplitude changes when the RF is modulated at an audio rate? Is it a speed issue? Would a DSO with a sample rate of (say)10Gs/s do it better?I really am struggling to get the idea of a graded index and how it might improve my situation. All my life I have used analogue scopes that do this kind of thing without any apparent difficulty and now it seems that the latest technology can't even do this simple thing!Sorry for my questions and also apologies if I am de-railing this thread.

author: David Hess
author_rank: Super Contributor
timestamp: June 22, 2014, 01:05:53 pm
content: Quote from: PedroDaGr8 on June 22, 2014, 07:53:21 amThis is only a recent feature for low end DSOs. Intensity graded displays have been available on most DSOs for decades in at least the form of variable persistence. It is one of the ways to avoid aliasing other than peak detection although with short record lengths signal detail is poor often resembling a sampling display.

author: David Hess
author_rank: Super Contributor
timestamp: June 22, 2014, 01:16:56 pm
content: Quote from: Andy2 on June 22, 2014, 09:55:39 amThe DSO's maximum sample rate probably does not matter in this case because it will be limited by the record length even if the record length is large.If your DSO is not showing at least the envelope then it could be a triggering issue. To save costs newer DSOs use digital triggering which occurs after digitizing and many of them have performance issues compared to the older analog triggering designs. To get around this you could trigger on the audio before modulation or after demodulation. With analog triggering, setting the trigger coupling to reject high frequencies would often help but a DSO with digital triggering may have problems if the trigger signal is subject to aliasing.My old DSOs which use analog triggering would have no problem displaying the RF envelope of an AM waveform but would fail to show the probabilistic nature of the signal inside the envelope leading to a rather ugly display compared to an analog oscilloscope.

author: Stray Electron
author_rank: Super Contributor
timestamp: June 22, 2014, 02:31:55 pm
content: I second Davorin's suggestion;LeCroy. I have a used Lecroy 9374CM and I LOVE it! They're easily to and cheap to upgrade with all of the options and good used used are selling on Ebay for less than a cheap Chinese scope. The thing that worries me about Chinese products are that there is little if any support and it it fails then there's no service information or parts and the Chinese made stuff isn't known for longevity! There's a very active LeCroy support group over on Yahoo and LeCroy has been generous about supplying service information and even option activation codes for their out of production models. They gave me the code to activate ALL of the options in my 9374.There have been some real bargains on used LOADED LeCroys on E-bay lately. This was one:<http://www.ebay.com/itm/LECROY-LC534AL-1-GHz-Single-2-GS-s-8-Mpt-Quad-500-GS-s-Color-Digital-O-039-scope-/261457452246?pt=BI_Oscilloscopes&hash=item3ce0141cd6&nma=true&si=lefTp37fbyKnI%252BgD5G16rSXgm2U%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557>PS: ScopeExplorer is free from LeCroy is you want to control your scope from a PC.

author: Andy2
author_rank: Contributor
timestamp: June 22, 2014, 03:08:18 pm
content: Thanks for you latest reply, David.That sounds much more like the issue I was having. I kept going back into the trigger menu and trying the various options, but the result never changed much. The Hantek kept trying to show me the individual RF cycles (badly!), even though the timebase was set for an audio rate. I guessed there must have been some kind of aliasing or undersampling going on, but I never thought to try external triggering from the mod source.Looks like I'll be keeping the old Tek!

author: Noise Floor
author_rank: Regular Contributor
timestamp: June 22, 2014, 06:35:53 pm
content: Similar to other suggestions, I'd recommend identifying the scope you want that is twice your budget, then search eBay for that scope; they can regularly go for 50% off new prices if not more.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: June 22, 2014, 06:56:55 pm
content: Quote from: Andy2 on June 22, 2014, 03:08:18 pmBy the way, the image you showed looks identical to one Dave used in his discussion on scope noise and intensity gradient. It might be the triggering on the Hantek is exceptionally bad. I'll see if I can find the exact part I'm taking about and I'll edit this post.EDIT: Actually I was wrong, it was the video about the DS2000 series. And it's not 100% identical but really really similar. This video should give you an idea of the differences in technology between older budget ones like the DS1052E and the newer budget scopes like the DS1074Z and DS2702A. This is not to say that the Tek isn't still a good scope worth keeping around. Just giving a bit more information for you to make an informed decision.

author: Andy2
author_rank: Contributor
timestamp: June 22, 2014, 10:43:47 pm
content: Many thanks, Pedro.That video is most impressive, the 2000 looks like a big advance on the older stuff. I note that his test of an AM signal was performed at 1 MHz, it would have been interesting to see how it coped at higher freqs. My Hantek was OK at 1 MHz (although it showed the same 'twitching' as the 1052 in the video). The higher I went the worse it got, and by 20 MHz it was useless. That 2202 certainly looks nice!

author: vk6zgo
author_rank: Super Contributor
timestamp: June 23, 2014, 04:11:11 am
content: Quote from: Andy2 on June 22, 2014, 09:55:39 am"Graded index" displays allow a nice "analog-like " display,but there are other factors causing your problems.Firstly,memory costs money,so there is a practical limit---it cost more in the past,& used up more physical space,due to the earlier technology used.Because of the memory limits in a particular DSO,they don't sample at the same rate at longer time/div settings as for shorter ones.This is fine if you are looking at simple waveshapes,but AM modulation is not a simple wave shape.Say you want to display two modulation cycles of a 1KHz modulated 20MHz signal:-From the setting,the DSO "thinks" you are looking at 2 cycles of a 1kHz signal,& adjusts the sample rate accordingly,with plenty of margin.Unfortunately,you have 20MHz RF there,too,which can't be correctly sampled at that rate.OK,why can't we force the thing to sample at the required rate?The problem there is that we would not be able to store the number of samples that would be produced over a 2m/s time interval.There are problems in reading out & displaying that much information in the time available to do this,too.Years ago,Tek & HP reps would come around to the TV Station where I worked,trying to sell their "latest & greatest".We would let them go through their spiel,then say:- "Try a PAL waveform displayed at Field rate"To get a nice usable display,you would usually set a 'scope to 5ms/div.At that setting,the sample rate was so low with these early DSOs,that they couldn't even resolve the 15kHz line rate stuff,let alone the video components at up to 5MHz.DSOs have gone ahead "in leaps & bounds" since that time,but some models may still have a similar if lesser,problem.A DSO which maintains a higher sample rate which allows faithful reproduction of such waveforms should be satisfactory,whether it has "graded index" capability or not.

author: Andy2
author_rank: Contributor
timestamp: June 23, 2014, 08:26:24 am
content: That's a very good explanation for digital virgins like me, and it expands nicely on previous posts. I now understand the problem - analogue scopes by their nature had virtually instant tracing and infinite resolution, so there was never the problem of 'where to put things' and how fast it could be done.I also now understand the idea of a graded display, which mimics the look of a CRT display. Many thanks to all. I wonder if there are any owners of a 2102 or 2202 that could try viewing a 50 MHz AM signal to see what happens? I assume the situation still worsens as the frequency rises?

author: exk
author_rank: Newbie
timestamp: September 20, 2016, 12:36:15 pm
content: Looks like Rigol DS1074Z is the cheapest 4 channeloscilloscope. But it drops sampling rate when all channels are used. So depending on measurement it could lead to aliasing.

author: psysc0rpi0n
author_rank: Frequent Contributor
timestamp: September 20, 2016, 12:52:02 pm
content: I just want to send a comment. From a review I saw, not sure if it was from Dave or someone else that compared a few scopes of this same range of price, they concluded that the Rigols are a bit below the competition regarding, for instance, FFT operations. If this is one of the features you need, look deeper around the web about that comparison and conclusion. I can also try to find it!I bought an MSO1104Z about a year ago but as I'm just a noob I can't tell if it is really good or not! I hope it can attend my demands for long time because I paid 971€ for it!CheersEdited:I think it was this comparison:https://www.eevblog.com/forum/blog/eevblog-845-oscilloscope-fft-comparison/

author: Fungus
author_rank: Super Contributor
timestamp: September 20, 2016, 12:52:43 pm
content: Quote from: exk on September 20, 2016, 12:36:15 pma) You can buy a DS1054Z for less money and unlock all the options, including 100MHz bandwidth (ie. you get a full DS1104Z with all options for the price of a DS1054Z).b) When all channels are on you get 250MHz sampling on each. 250MHz sampling is enough to reproduce a 100MHz signal without aliasing (it's over twice the Nyquist limit).(and be aware that ALL 'scopes in this price range will drop the sample rate when more channels are used)

author: zapta
author_rank: Super Contributor
timestamp: September 20, 2016, 01:16:42 pm
content: Quote from: Andy2 on June 23, 2014, 08:26:24 amIt's like saying that analog voltmeters have infinite resolution. Very far from the truth, even in practical terms.

author: rstofer
author_rank: Super Contributor
timestamp: September 20, 2016, 04:14:14 pm
content: This is a zombie thread (6/2014) and most of the posts predate the DS1054Z and certainly predate the latest firmware.Nobody would seriously consider the DS1052E these days.