Current UK Oscilliscope prices... - Page 1
Forum section: electronics / testgear

author: MrSzymon
author_rank: Newbie
timestamp: December 13, 2018, 12:05:27 am
content: Hi there,I am a long time lurker of this forum and watcher of Dave’s videos; I’ve never needed to post before so I haven’t created an acccount until now! I work with computer security for a living, with relevant qualifications (BA, MSc, CEng), and I am a licensed radio ham (M0GZP) with a long term interest in electronics.I find myself in need of a new oscilloscope (the old one I had, an analog two channel, has finally died a horrid death, beyond economic repair, so it has been cannibalised for parts to help a friend fix his). So of course I spent some time researching the options and opinions of those on here, and I am trying to work out what makes most sense at current UK prices.It seems that my options in the UK at the end of 2018 are:- £50: another old analogue scope (will probably last until I die of old age)- £90: a handheld 40mhz scope that looks like a multimeter (similar to fluke portascopes of old?)- £180: a cheap Chinese 100mhz 2 channel scope, with a 7” screen (any preferences in the cheap brands? Hantek? Owon? Other?)- £270: Rigol DS1052E, 50mhz 2 channel scope, with a small low resolution screen- £360: Rigol Ds1054Z, 100mhz 4 channel scope, a 7” screenThe 1054Z is obviously the winner in terms of features and function. But at twice the price of cheap Chinese I am not sure I will ever need the four channels. That aside, is it twice as good?The 1052E seems to be the equivalent of the cheap Chinese scopes, but with a worse screen. If I’m buying a new scope I’d like a better screen, my eyes aren’t what they used to be! Is it better? 150% better?The Hantek or equivalent seems to me to be the front runner in terms of price/performance at the moment. Is it four times better than an old analogue scope? I think it might be from what I have seen and read.I don’t know about the handheld thing, but they seem pretty impressive - and certainly portable! I like the idea of having the scope with me when operating mobile, out in a field somewhere.Have I missed any options in my “state of the union” above? What thoughts/opinions do you have on my choices?-simon

author: tggzzz
author_rank: Super Contributor
timestamp: December 13, 2018, 12:32:04 am
content: Quote from: MrSzymon on December 13, 2018, 12:05:27 amYes, because what makes most sense depends on what you want to measure.The usual errors are:for digital signals, going from clock speed/period to scope bandwidth. All that matters is the digital signal transition time, independent of clock frequencyconfusing sample/s with bandwidth; the two are entirely orthogonal

author: MrSzymon
author_rank: Newbie
timestamp: December 13, 2018, 01:26:11 am
content: What do I want to measure? I guess that’s a good question. I want to take measurements of voltage over a period of time, displayed as a waveform ;-)More seriously, I’ve used a scope for various things. It’s all about visualising whats actually happening in a circuit. Tracking down interference is a big one - simple things like finding that a switching power supply isn’t producing a pure dc signal but has an ac component which is causing a hum on my radio when I transmit. Tough to find with just the DMM!Of course, it’s much more than that. I’ve used the scope for all sorts of things. Most recent before it died was testing a linear amplifier. One channel measured the input, the other the output, then we changed the voltage scale so the waveforms looked the same and superimposed; this gave a good indication that the problem wasn’t with the amplifier itself which was working well. I also used the scope to measure the actual power output of the amp (while it was piped in to a dummy load).Another thing I’ve done before is connect a simple RF detector to the scope to look at signals on the amateur bands - I remember that being very useful when I was having trouble with an antenna I was building for 17 metres.Of course, what you will quickly note is that none of the things I describe above need anything more than an old analogue scope! So I am not sure how useful it is :-/. I know the newer scopes can do all sorts of amazing things (logic analysers, mathematical functions, just reading about it is an education!), but mostly what I need is to be able to plot voltage over time...

author: tggzzz
author_rank: Super Contributor
timestamp: December 13, 2018, 08:47:07 am
content: Yes, but all tools have their strengths and weaknesses - so you have to choose your poison. Despite what you might read, the low-end digitising scopes make compromises that might affect what you do. You should carefully consider what bandwidth and voltage resolution amd linearity you need for noise measurements.There's also the consideration that is a scope theonlytool you need.If you are only interested in up to ~10MHz bandwidth, seriously look at the Analog Discovery. Key points: 14-bit native resolution (cf 8 bit), two channels, 2 channels AWG, 16 bit pattern generator, 16 bit logic analyser, all combined to make a spectrum analyser, network analyser, etc.My strategy would be:if you need >50MHz bandwidth, then get a good old working analogue scope, e.g. Tek 465/475/485/24x5. They are surprisingly cheapif you need 20MHz bandwidth, get an old working analogue scope for £1/MHzif you think you need a modern 100MHz DSO such as the Rigol, try one first on your problems - you may be surprisedfor RF problems, use a spectrum analyserMy bench contains a Tek 485 (or 2465) for signal integrity and general purpose use, and an Analog Discovery when I need post-processing or single-shot capture. I have too many other scopes and must sell some

author: bd139
author_rank: Super Contributor
timestamp: December 13, 2018, 09:14:07 am
content: 1054Z is the best option if you are lazy, don't mind spending the money and want something that works tomorrow at the cost of being noisy, laggy and probably last 3-5 years before it blows up irreparably.Tektronix 4xx is the best option if you don't mind fixing it occasionally, have the space, don't have any really slow problems to deal with and don't have any back problems.I'm currently using a Tektronix TDS210 as my main scope which incidentally blew up this morning (looks like primary filter cap so about £3 to fix). This cost me £60 plus £4 for a couple of new BNC connectors and £45 on three new Tektronix probes. The "spare" unit is a 250MHz Tek 475A I paid £50 for.Babbling aside, unless you need it now, as tggzzz says work out your problem domain, lurk and pounce when something ridiculously cheap for what it is turns up. This happens all the time! Buy the Rigol DS1054Z if you need something now (get it from Telonic - they're pretty good and take offers on their ebay auctions of £20 or so off the price).I'd like an Analog Discovery as mentioned but I would probably kill it dead and the PC attached to it in 30 seconds flat.

author: Fungus
author_rank: Super Contributor
timestamp: December 13, 2018, 10:31:34 am
content: Quote from: bd139 on December 13, 2018, 09:14:07 am100% pure FUD. The DS1054Z isn't the best selling oscilloscope for no reason.Quote from: bd139 on December 13, 2018, 09:14:07 amLet's hope so.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: December 13, 2018, 10:39:51 am
content: Quote from: bd139 on December 13, 2018, 09:14:07 amMany moons ago I started with +-20V input scope and went straight to poking low power HV (plasma ball power sources etc) with x100 probe. No damages ever. Sometimes used ADUM4160 based USB isolator (use ext power to it!) just in case. USB 2.0 scopes will probably all work with these with some wfm rate hit.Otherwise Siglent SDS1000X-E series is probably most balanced cheap scope. There should be no big surprises in regard to waveform shapes and amplitudes compared to say good analog scope.

author: Fungus
author_rank: Super Contributor
timestamp: December 13, 2018, 10:47:27 am
content: Quote from: MrSzymon on December 13, 2018, 12:05:27 amYes.Quote from: MrSzymon on December 13, 2018, 12:05:27 amVery long in the tooth now.Quote from: MrSzymon on December 13, 2018, 12:05:27 amLooks good in a brochure but the firmware/functions (ie. usefulness) are terrible.Quote from: MrSzymon on December 13, 2018, 12:05:27 amI don't know exactly which models you're referring to but usually very limited input voltage ranges, low bandwidth (not much more than audio), horrible to use (only a few push buttons for everything).Quote from: MrSzymon on December 13, 2018, 12:05:27 amIn the same price range as the DS1054Z there's a 2-channel Siglent and the GW-Instek GDS1054B. The GW-Instek is a bit more "analog" than the others and might be a good match for a ham-radio guy who makes amplifiers.All can be bought online from places likebatronix.

author: Fungus
author_rank: Super Contributor
timestamp: December 13, 2018, 10:48:30 am
content: Quote from: MrW0lf on December 13, 2018, 10:39:51 amThey're designed to survive "educational environments".

author: bd139
author_rank: Super Contributor
timestamp: December 13, 2018, 01:19:54 pm
content: Quote from: Fungus on December 13, 2018, 10:31:34 amIt only sells because it’s cheap and the value proposition is good. Quality it is not. Better quality than crap yes.McDonald’s sell a lot of food.Also as a fellow M0, the DS1054Z isn’t that useful versus anything else out there. Which is why I sold both of mine. For amateur radio use you’re better investing in a half decent signal source such as a DG1022Z (oerfectly fine for all the currently usable HF bands) or something and using whatever scope you can get your hands on.The 475A worked out for me because that’s usable well into 2m band if you terminate it at the scope and use substitution based measurements. There are no new 250Mhz scopes for £50.

author: Fungus
author_rank: Super Contributor
timestamp: December 13, 2018, 01:43:15 pm
content: Quote from: bd139 on December 13, 2018, 01:19:54 pmYep, but Rigol isn't the lowest of the low. Stop pretending it is. If it was really that bad then there'd be competition.Rigol is more like Fosters Hollywood or something like that. Nothing amazing but certainly a step up from McDonalds.

author: bd139
author_rank: Super Contributor
timestamp: December 13, 2018, 01:58:44 pm
content: I rate Hantek about the same as the bins out the back of Farm Foods if that clears up the ranking.Honestly it's notbadbut it's also not thatgood. Much like McDonalds it fills a hole.

author: MrW0lf
author_rank: Frequent Contributor
timestamp: December 13, 2018, 02:10:56 pm
content: Quote from: bd139 on December 13, 2018, 01:58:44 pmSubway then!

author: tggzzz
author_rank: Super Contributor
timestamp: December 13, 2018, 03:11:41 pm
content: Quote from: bd139 on December 13, 2018, 01:19:54 pmSeems sensible, but I'll note that the 475A input will then be 50ohms//20pF (followed by a 1Mohm attenuator) which affects the VSWR. Same is true for the Rigols. OTOH the Tek 485 has a "proper" 50ohm attenuator.But that's probably irrelevant to the OP, since functioning 485s are rare and I'm not letting mine go

author: bd139
author_rank: Super Contributor
timestamp: December 13, 2018, 03:23:41 pm
content: I did some measurements on that actually using my 818ND as a signal generator. Setup was: 818ND -> 6dB pad -> RLB [ -> 50R terminator -> scope | -> power meter ]0-25MHz it was a flat 26dB (I suspect limited by the directivity of my bridge) return loss so VSWR 1.1:1. 144MHz it was 19dB so around VSWR 1.2:1. At 433MHz it was a still quite respectable 9dB so VSWR 2:1. Scope was totally useless here obviously though.The TDS210 was slightly better but hardly anything to write home about. I suspect that the outcome was starting to be defined by my RLB and terminator after about 200MHz.485 would be really nice but they eluded me the last couple of times (apart from that one I couldn't be bothered to go and get)

author: james_s
author_rank: Super Contributor
timestamp: December 16, 2018, 05:57:05 pm
content: Unless you have a specific need for an analog scope such as cheap high bandwidth or XY mode I would recommend going with a DSO. Analog still has a few advantages but once you're already proficient at using a scope the DSO offers a lot of cool tricks that make life easier.