I've spent a week thinking about a new oscilloscope, help please? (1k-3k budget) - Page 1
Forum section: electronics / testgear

author: gperoni
author_rank: Contributor
timestamp: July 31, 2018, 10:54:08 am
content: I just want to be done with this decision and go back to designing things!The signals I would like to look at are:- IQ baseband signal, differential but I don't think it matters, 20 MHz- Your typical boring CMOS clock, <= 40 MHz- 70-140 MHz parallel busThe other signals I would like to look at but I probably cannot afford are:- DDR2, 400MHz- SerDes, too high of a frequency to even comprehend, it's probably best to hope the design just works.I currently have your typical super cheap hacked rigol and a saleae logic 8 (I mostly work with RF).So here is is my thought process and what I've been looking at:- I'm ok with any hacking up to and including a couple of days of soldering.- I don't think I need a MSO. I believe my logic 8 gets the job done. It would probably be a nice to have feature, but only if the scope is big/new enough to make the interface better to use than my pc. Sure looking at some signal integrity and triggering from it would be nice but it doesn't sound like a must have.- I'm considering those scopes based on their resale value. I'm ok with spending 5k if I can get a good chunk of that back selling the scope in 6 months assuming that the project doesn't work out as planned.- I'm in Europe and I can't find that much on Ebay. I even looked at the .com website, it looks to me like this is the wrong time of the year for used oscilloscopes. But I need it now.So scopes I've been looking at:1) Rigol DS4000, hacked to 500 MHz, Euro 2000 (I don't have to worry about VAT). The same with MSO can be had for around Euro 2800.2) Rigol DS7000, the 200 MHz version for Euro 3000 seems attractive to me. With MSO it's 4000, it gets to 5500 with decoding. It seems like a stupid purchase to me because the moment it's hacked (tomorrow or in two years) the 2500 spent on unlocks will become worthless.3) Siglent SDS2204X, Euro 1300 for a 200 MHz scope, an additional Euro 400 for MSO and unlocks. The 300 MHz version is 1700.4) Keysight 3000T series. Let's say the 4-ch MSO 100 MHz option is 5k? It should be possible to hack the scope to 500 MHz and unlock all the options. I can't find it used on Ebay. The non-MSO 100 MHz option is Euro 3612. The 3000A series seems barely cheaper and I believe will have a slightly lower resell value, so I don't see the point.5) The R&S RTB2004 is 2700 for 200 MHz with no MSO, adding MSO and decoding gets you to 4500 for 200 MHz. This is the scope with the nicest screen and probably interface, that should mean less problems using it, that makes it attractive.6) A 2 channel 200 MHz Siglent is basically free, Euro 330. Some part of me feels like I should just go with this scope and re-evaluate in a month.An extra, additional problem is probes. I sort of have the feeling a 500 MHz scope is going to be useless without at least one active probe.I'm lost guys.

author: nctnico
author_rank: Super Contributor
timestamp: July 31, 2018, 11:57:27 am
content: I'm missing the GW Instek MSO2000 and GDS2000E from the list.If you already have a cheap scope then I'd scratch Keysight, Rigol and Siglent from the list. Outdated (slow) platforms and with the last two bugs on top. The memory in the Keysight 3000T is not enough (especially since you'll have 1/4 or less available for actual use).If you want to look at high frequency signals a second hand high end oscilloscope offers good value for money. I'd spend between 1k and 3k euro on an Agilent or Lecroy. High speed probing doesn't need to be extremely expensive. There are cheap AC coupled FET probes on Ebay and you can buy passive divider probes for between $100 to $200.The RTB2004 is nice but it is a lot of extra money for a bigger screen compared to the GW Instek MSO2000.Resale value is tricky. Test equipment devaluates faster than a car.

author: EEVblog
author_rank: Unknown
timestamp: July 31, 2018, 12:29:56 pm
content: That's a heck of a price range!The problem, as you've found, is that such a large possible price range adds a lot of possible confusion and conflict.I'd first ask, do you need any other gear? i.e spend maybe $2-3K on the scope and get some other goodies along with it?

author: EEVblog
author_rank: Unknown
timestamp: July 31, 2018, 12:32:04 pm
content: You should factor in that the RTB2004 is the only one with a 10 bit converter.

author: In Vacuo Veritas
author_rank: Frequent Contributor
timestamp: July 31, 2018, 12:46:59 pm
content: You'll find that a logic analyzer will do just great for all your boring CMOS stuff and single-ended logic. What is the purpose of seeing every curlicue and wiggle on a scope for a digital signal, given that it will change depending on the length and location of the ground clip?Follow some simple design rules and all the "too high to comprehend" (it's just a number, is a motor revving at 18000 RPM is also "too high to comprehend"?) will just work.Why do you want to see DDR2 waveforms? It's a protocol, just read the datasheet. Who cares if there's a 12mV wart on a falling edge 0.12ps after the burp on the riding edge? Follow the guidelines, it will work. All the engineering has already been done for you.The amount of self-inflicted drama you noobs go through...

author: Mr Nutts
author_rank: Regular Contributor
timestamp: July 31, 2018, 12:59:49 pm
content: Why do you want to spend so much money for a new oscilloscope? In 6 months you'll lose a large part of the original purchase price when you try to sell your scope which is a waste.Ebay is full of used scopes that can do everything you want, and shipping to Europe shouldn't be much of a problem (I recently met a guy in the UK who buys a lot of equipment from the US). You just have to know what you're looking for and not fixate too much on the list of scopes you have.For example, a few months ago I bought a Lecroy Waveruner 2 LT574 scope which is a 500MHz 4GSps four channel scope for $800, and with the added options that became available through the "option recovery" thread it now can even demodulate I/Q signals (option DEMOD). You also get the different diagrams like constellation diagram.There's a review of the smaller model LT264 (which I also have):https://www.eevblog.com/forum/testgear/lecroy-waverunner-2-lt264m-review-and-(partial)-teardown/The only feature that I occasionally miss is serial decoding. I think the successor model Waveruner 6000 had this. This is based on Windows and they are also becoming cheaper (these scopes were $10k when new, excluding the options). Options can be "recovered", too, apparentlyLecroy probes are also often quite cheap, even active ones. I bought two HFP1000 1GHz active probes for $180 each.For you a 350MHz Waveruner LT264 or 6030 could well work as well for you as a new $5k scope. There are probably other alternatives but I only know these.

author: gperoni
author_rank: Contributor
timestamp: July 31, 2018, 01:32:48 pm
content: As I said I don't see a need for a MSO as the logic analyzer I have works fine for me.I also listed DDR2 as too expensive and I agree with your sentiment, In Vacuo Veritas.I was playing with the idea of probing DDR2 signalsbecause of my very bad experiences in the past, however, even by assuming I can get a 2GHz scope and probes for 2k off ebay I still don't see that as a good investment for a single bus, that I agree, should be just a "follow the guidelines and forget". I've also heard from a guy that did signal path integrity for an Intel reference design once how much of a pain that was, even for them.I would love to snatch something off ebay, I'm absolutely ok with used equipment! I can even get the import VAT refundedIt just seems like I can't find discounted, non-ancient rigol, siglents or keysight/agilent off ebay. It does however seem like there are nice prices for some Lecroys, that I didn't look for before this morningLooking at IQ constellation diagrams doesn't seem like something I have a use for (I can already do that on the RF side and the modulator would still require its precise offset/vpp so yeah), but it's nice to know they can be hacked.

author: fonograph
author_rank: Frequent Contributor
timestamp: July 31, 2018, 01:46:15 pm
content: I would try to score used LeCroy HDO 4000.Rohde & Schwarz have website for used equipment,its mostly demo units,I think I saw RTO there for that price.Whatever you do,with this kind of budget,avoid chinese scopes like plague.Their track record of software bugs and handling of bugs is so bad its like surreal comedy,or nightmare if you made mistake and bought one of these pieces of schmitt

author: Mr Nutts
author_rank: Regular Contributor
timestamp: July 31, 2018, 01:53:39 pm
content: There's currently a lecroy 6030 in the UK if that's closer to you:https://www.ebay.co.uk/itm/LeCroy-WaveRunner-6030A-VL-4Ch-350MHz-Digital-Oscilloscope-24M-5GS-s-Options/123226363158

author: Zucca
author_rank: Unknown
timestamp: July 31, 2018, 02:22:41 pm
content: https://www.ebay.de/itm/Keysight-Used-DSOX3054A-Oscilloscope-4-channel-500MHz-Agilent/183176577797?hash=item2aa62cc305:g:QMwAAOSwl4Va0EL5

author: gperoni
author_rank: Contributor
timestamp: July 31, 2018, 02:36:17 pm
content: It looks like this thread turned into a "what is the best scope I can find on ebay for just less than 5k contest"I would rather not go that high.

author: fonograph
author_rank: Frequent Contributor
timestamp: July 31, 2018, 04:12:52 pm
content: Quote from: gperoni on July 31, 2018, 02:36:17 pmThen edit your original post!You come here,tell ppl you have 5k budget,ppl recommend you 5k scopes and your like "Whoa! 5k ? That is too much brah". So either you want or down want a 5k scope,its either "omg 5k too much!!" or "thanks for suggestion bro,I will buy that".First make up your mind and decide what money you want to REALLY spend.

author: gperoni
author_rank: Contributor
timestamp: July 31, 2018, 04:27:59 pm
content: Sure, I changed it to 1-3k. My reasoning with using 5k was that I didn't want to exclude very nice deals just over the 3k range. I apologise, I should have explained.

author: Zucca
author_rank: Unknown
timestamp: July 31, 2018, 05:20:00 pm
content: That was a good deal...if you want really the best bang for the bucks buy a MSOX3014T and thenhttps://www.eevblog.com/forum/testgear/keysight-3000t-scope-1-ghz-hardware-upgrade-mod/Good Luck!Ciaogperoni!

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: July 31, 2018, 05:51:01 pm
content: If you go with the Keysight, I highly recommend the 3000T over the 3000A. I'd also keep an eye on our eBay shop, that's where you'll find the best deals on used gear that also have a warranty.

author: nctnico
author_rank: Super Contributor
timestamp: July 31, 2018, 07:41:33 pm
content: Quote from: gperoni on July 31, 2018, 04:27:59 pmThere is a bit of a vacuum in the 1k to 3k price range. The A-brands have some oscilloscopes in that price range but the value for money isn't that great. If you want to make a step up which offers value for money then you'd have to spend way over 5k.

author: fonograph
author_rank: Frequent Contributor
timestamp: July 31, 2018, 07:41:48 pm
content: Quote from: gperoni on July 31, 2018, 04:27:59 pmYou wrote you want to do 400 MHz DDR2,if you want it to resemble square wave you need 5x bandwidth.Here is ex demo RTO 2 channel 600 MHz for 4900$https://shop.rohde-schwarz.com/bargain/r-srrto1002-2-1.htmland here is same scope except this time 2 GHz for 6900$https://shop.rohde-schwarz.com/bargain/r-srrto1022-2-1-1.html

author: tautech
author_rank: Super Contributor
timestamp: July 31, 2018, 10:37:17 pm
content: Quote from: gperoni on July 31, 2018, 04:27:59 pmWhich begs the question; what scope do you have now ?You can get a SDS1202X-E (sure only 2 channels) for less than an MSO option for most scopes.

author: RobBarter
author_rank: Regular Contributor
timestamp: August 01, 2018, 12:16:06 pm
content: gperoni - I admire your restraint. Usually when I start looking for a new piece of kit, my perceived budget increases the more I lookYours has actually gone downBut thanks for asking the question, it's exactly the advice I'm looking for. A scope upto approx. £3k. New or 2nd hand. 75% for my own 'hobby use' (building 1.2GHz and upwards ham radio gear) and 25% for work I that can just about justify against my business (one man band!) wrt. micro controllers. That LeCroy 6030VL does look interesting, though never thought of the LeCroy route before as was leaning toward R&S or PicoTech.

author: gperoni
author_rank: Contributor
timestamp: August 01, 2018, 01:51:02 pm
content: This is another LeCroy around this budget, from a new seller:https://www.ebay.ie/itm/LeCroy-WavePro-7Zi-2-5-Ghz-40GS-s-725Zi-HDTV-option/113175679343I ended up ordering a RTB2004 with 200 MHz upgrade and no extra. The guy selling his at a 20% discount on the forums gives me hope for its resell value, and I believe I will love the peaceful interface and the noiseless operation -- those were actually the two biggest selling points for me; I'm tired of hating my scope.Good luck with your choice!

author: Mr Nutts
author_rank: Regular Contributor
timestamp: August 01, 2018, 03:30:09 pm
content: Quote from: gperoni on August 01, 2018, 01:51:02 pmNew seller with a feedback of 1 which he got as a buyer for buying something from a seller of cheap tat? Smells like a scam to me.

author: Mr Nutts
author_rank: Regular Contributor
timestamp: August 01, 2018, 03:41:30 pm
content: Quote from: RobBarter on August 01, 2018, 12:16:06 pmAt college they only had Tektronix scopes but I found them horrible, they were slow and crashed regularly. After college I wanted something which was not like Tek and someone suggested lecroy which I never heard before.I found a lot of information about lecroy scopes new and old through google which brought me here. There's a lot of good info written by a former member, it helped me a lot to make the best of use of my old lt264 and my later lt374.

author: RobBarter
author_rank: Regular Contributor
timestamp: August 01, 2018, 04:03:06 pm
content: Quote from: Mr Nutts on August 01, 2018, 03:30:09 pmand looks like he's looking for closer to 8000 (if it is real of course). I'll skip this one.

author: Bud
author_rank: Super Contributor
timestamp: August 01, 2018, 04:15:52 pm
content: Want to do serious no-shit work or work for someone - stay with traditional non- Chinese brands. Hobby fun work - brand does not matter in general.

author: nctnico
author_rank: Super Contributor
timestamp: August 01, 2018, 10:27:17 pm
content: Quote from: Bud on August 01, 2018, 04:15:52 pmIn general I agree but I really have to make an exception for GW Instek and MicSig. Their equipment delivers on the promised specs and is not buggy but it is also more expensive.

author: tggzzz
author_rank: Super Contributor
timestamp: August 01, 2018, 10:41:56 pm
content: Quote from: gperoni on July 31, 2018, 10:54:08 amA key part of design is that you specify what and how you test. Therefore you shouldfinishdesigningbeforeconsidering what equipment to buy.QuoteIrrelevant number. Theonlything that matters is the transition time. FFI and concrete examples, seehttps://entertaininghacks.wordpress.com/2018/05/08/digital-signal-integrity-and-bandwidth-signals-risetime-is-important-period-is-irrelevant/QuoteOnce you know you your analogue signal will be correctly interpreted by your digital receiver, flip to debugging in the digital domain by using a logoc analyser.QuoteWithout defining what you are looking for and why, then using skill and imagination to think of alternative ways of reaping the benefits, you are likely to spend more than necessary.QuoteGood.Now you will have tothinkwhat youneedto achieve, and then useskillandimagination. See my .sig, and translate that to electronics! I designed, constructed and tested my first computer (with 128bytesof RAM) using only an analogue voltmeter, some switches, and some LEDs.Remember the old aphorism: a week in the lab can save an hours thinking about your circuit.