High end scope advice for a kid? - Page 1
Forum section: electronics / testgear

author: QuantumPhys
author_rank: Contributor
timestamp: July 07, 2014, 02:08:07 am
content: Hi everyone,I have recently just saved up enough to get a "high end" scope-up to a Agilent 3000X or a new Lecroy waversurfer 3000. However, I need help evaluating if I should get one.Firstly, I need to clarify: I just turned 14 yesterday. I am just a hobbyist, and I started my interest in electronics when I was 8. All the money are bits and pieces I got from competitions, saved up, or parts from my parents. I plan to use my money solely on electronics.I mainly enjoy doing RF electronics nowadays, making random things for myself like LNAs, filters, frequency multipliers...just to play around with as I can get PCBs fabbed very cheap. I reach up to 10GHz with up/downconverters, but for the main part, do around 1-2GHz stuff. I am also working on building the DIY Scotty spectrum analyzer. I also sometimes do lower frequency analog projects, like scope amplifiers, and simple instruments. Also, I do still play with digital, like with STM32s, and FPGAs, making small projects like driving 64x16 LED matrices.So here comes the question: is it justified for me to buy such a scope? Can I use it with my current knowledge, or is it better to spend the money on other things? I currently use a DS1052E and a Tek 2445B, and I am seriously sick of the DS1052E (low bandwidth, terrible FFT, no intensity grading, slowness of GUI, lack of decode...).I would really like a new scope, but should I just get a DS2072 (and "upgrade" it at home), or get something I have been dreaming for for years, like a Agilent/Keysight 3024X or a Lecroy Wavesurfer 3000? Or, should I just save the money and get myself a VNA or synthesized signal generator?The most important factor here is I am just a kid and have no means of income.Thanks a lot for helping! I would honestly really need advice on whether it is "ethical" for me to buy such an expensive piece equipment.Best regards,Sihao Huang

author: astraios
author_rank: Contributor
timestamp: July 07, 2014, 02:22:07 am
content: Sihao Huang,Personally I think that if you want to purchase any piece of equipment and your parent are ok with it, I see nothing wrong with it.I don't see any "ethical" problems with it, just make sure you have your parents permission.If I had a kid I would prefer for him/her to learn electronics, than play video games all day as most kids of your age do.Keep it up.

author: tautech
author_rank: Super Contributor
timestamp: July 07, 2014, 02:28:10 am
content: In your position, I would seriously consider your career path to help you decide how much to spend.If you become an EE, it is likely you will have access to high end gear in the future at your employer's.But you may feel, at your age, this is a while away and you need/want your own gear until then.In the high-end range(really mid-range) things are every-changing and the model you choose will likely be out-spec'ed in short order. This should guide your decision.Take your time, dream up someSihaotest rig/procedure and get some hands-on experience with the models you desire.

author: marshallh
author_rank: Unknown
timestamp: July 07, 2014, 02:46:16 am
content: DS2072 is the best "all-round" scope for the ptrice currently. However, if you don't mind a noisier boat anchor scope you can troll ebay for used Tek/Lecroys and get more bandwidth. You could easily get a 1ghz-2ghz analog bandwidth scope from the 90s for the same price you'd spend on that Rigol, but you need to be patient and vigilant. Also you'll need better probes for those bandwidths which cost more money, but can still be gotten used.

author: QuantumPhys
author_rank: Contributor
timestamp: July 07, 2014, 03:22:16 am
content: Thanks everyone for the advice! My parents do not actually object to such an expensive scope, but the biggest question to me is if I will be able to use something like a Agilent 3000X, or would it be enough for me to just get a Rigol, and then spend the rest on getting a VNA or RF generator. I certainly do not wish that I would waste my money (and my parent's) on such an expensive item!By the way, I do not actually plan to be an EE (my parents do not really want that...) and doing electronics is purely my hobby. I will therefore, have no means of getting high end stuff in labs.

author: polishdude20
author_rank: Contributor
timestamp: July 07, 2014, 03:25:56 am
content: Quote from: QuantumPhys on July 07, 2014, 03:22:16 amAww man what! A kid like you is perfect for the EE career path. It's a shame you're being steered in a different direction. Mind if I ask what that direction might be?

author: VK5RC
author_rank: Unknown
timestamp: July 07, 2014, 03:41:06 am
content: What a choice! If RF really interests you, (as it does with me) a good spec analyser (good second hand) perhaps also should be considered. Once you get over a GHz the scopes get v expensive, for me that is the area where the fun begins. Note for me this is a hobby, but I would use the spec analyser 2-3x the amount I use my scope.

author: astraios
author_rank: Contributor
timestamp: July 07, 2014, 03:43:02 am
content: Sihao, I think you could be a great EE.Close your eyes and imagine yourself working as an adult.Choose a work that will makeyourself happy, not what your parents want and try to explain it to them.I hope I'm not being disrespectful, but usually a work choice is for life, so choose what makes you happiest so you'll have no regrets.

author: pickle9000
author_rank: Super Contributor
timestamp: July 07, 2014, 03:47:38 am
content: I would go for multiple bit's of gear, more fun with more toys.I think your life will drag you where it want's to be EE or not sounds like you are in for a good life.

author: w2aew
author_rank: Super Contributor
timestamp: July 07, 2014, 03:50:40 am
content: Quote from: QuantumPhys on July 07, 2014, 02:08:07 amI may be a bit biased, but have you considered a Tek MDO3000? With all of the RF stuff you're playing with, the built in spectrum analyzer will come in real handy. There's currently a promotion running where you get the upgrade to the 3GHz spectrum analyzer for free, along with one serial decode module for free. I think the promotion runs until the end of August or September.

author: QuantumPhys
author_rank: Contributor
timestamp: July 07, 2014, 04:08:29 am
content: Wow, thanks for all that great advice! I really do enjoy EE, but as for direction I will go towards, I am not so sure. My parents keep talking to me about economics, while my grandparents would prefer me to do quantum computing (which would, probably, still involve RF and digital).

author: QuantumPhys
author_rank: Contributor
timestamp: July 07, 2014, 04:14:55 am
content: Quote from: w2aew on July 07, 2014, 03:50:40 amHi Mr w2aew (such an honor to receive a post from you)!I honestly did not know that there is such an offer! I will seriously consider it, or at least ask for a demo. I actually have a Tek 2715 spectrum analyzer (modded to be 50ohms instead of 75), but a modern spectrum analyzer will definitely be useful. I am not sure if I can justify the price as a kid though, no matter it being Tek, Agilent/Keysight, or even Lecroy.

author: QuantumPhys
author_rank: Contributor
timestamp: July 07, 2014, 04:18:54 am
content: Quote from: VK5RC on July 07, 2014, 03:41:06 am:)that seems so true...Being using my Tek 2715 so much that I forget that there is something called a scope for debugging...May I know if you would consider a good scope useful though?

author: EEVblog
author_rank: Unknown
timestamp: July 07, 2014, 04:54:04 am
content: Quote from: QuantumPhys on July 07, 2014, 02:08:07 amNo.QuoteYes!QuoteThen consider upgrading to say the Rigol 2000. Hugely better bang-per-buck than spending $3K+ on a 3000X series.QuoteIf you are into that sort of stuff, then start looking for used VNA's on ebay.QuoteThen you most certainly shouldn't be blowing it all on a "dream" scope.Be practical. A Rigol 2000 will do more for much less money.At the end of the day a scope is going to be mostly used for basic stuff. Spending $3K+ on one is silly in this situation. You are far better off getting a bunch of purpose designed 2nd hand test gear. You are US based, so great old gear like this is easy and cheap to get.QuoteSome will say you must spend years suffering with a 20MHz dual channel analog...

author: TerraHertz
author_rank: Super Contributor
timestamp: July 07, 2014, 05:04:55 am
content: Awesome! It's great to see someone young with such a clear idea of what they want, and considering options so wisely.This line cracked me up: "grandparents would prefer me to do quantum computing". Sounds like something from a SciFi script, set about 100 years in future. "grandson, why don't you stick to a respectable, well established field like quantum computing? Forget about this newfangled scalar fuzz engine stuff, it's just a fad!"I wonder why you are apparently only considering purchase of new equipment? For the same amount of money you can get several top-of-line instruments from just a few years ago. Still easy to get spares, documentation, even complete units as backups.Also, speaking with people familiar with older models from long use is a lot more reliable than information on brand new units, which still tend to be surrounded by marketing hype, and confirmation bias of recent buyers who will be justifying their own expenditure to make themselves feel good.With new gear you are stuck with formal channels for any repairs or recals necessary. This can be extremely expensive, and must be factored into the cost of ownership if you're planning to be using it for years.One last comment, about economics as a career. I wouldn't be surprised if in the next few years there are some economists to be seen hanging from streetlamps. Change is in the wind.

author: Bored@Work
author_rank: Super Contributor
timestamp: July 07, 2014, 05:05:19 am
content: You know the definition of a hobby? A way to waste money and time in exchange for fun.So if you have the money, if your parents are OK with it, and if you think you will get your money's worth of fun out of it then go for it.But, would I be your parent I would suggest alternatives.Alternative 1) Get a cheaper oscilloscope and use the remaining money for other equipment. E.g. good and safe multimeter(s).Alternative 2) Get a cheaper oscilloscope and place the remaining money in a savings account. There are other kinds of fun than just electronics. E.g. traveling, buying your first car in a few years, going to the cinema or a concert, etc. Having some money in the bank to be able to buy something when you want, is a very nice thing.But whatever you do, continue what you did to get that money in the first place. You apparently did some things right to get enough money for a good oscilloscope.And last, have a look at one of Dave's very old videos where he talks about having some screw-you-money in the bank. It doesn't apply to you now, but will in a few years, when you work.

author: pickle9000
author_rank: Super Contributor
timestamp: July 07, 2014, 05:12:31 am
content: Economics, CFO at a large test equipment company.

author: EEVblog
author_rank: Unknown
timestamp: July 07, 2014, 05:33:29 am
content: Quote from: Bored@Work on July 07, 2014, 05:05:19 amYes. One of the things my dad taught me was the value of having money in the bank.When I bought my first scope (Kikusui 20MHz dual channel analog) as a teenager, I made sure I didn't blow all my money on it.BTW, it was a new scope, as back then the 2nd hand market constituted the local Trading Post newspaper. And rarely was a scope ever advertised in there.Kids these days (esp US based ones) have an awesome array of 2nd hand gear to chose from.You can literally build a $100k lab of top end 2nd hand gear with only a few $k

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: July 07, 2014, 06:50:00 am
content: Quote from: QuantumPhys on July 07, 2014, 02:08:07 amI have to concur with TerraHertz here in that you are ignoring the used market. For example, for the price of a DS2072 you could certainly find something like a LeCroy WaveRunner 2 which gives you 4 channels and much more advanced FFT, maths and signal analysis capabilities than you will find in any Rigol or lower class Agilent/Tektronix/LeCroy scope. There are various software options available (i.e. Power Analysys which is great if you work with switch-mode PSUs, advanced jitter analysis etc.) which with some luck(!) may be optainable for free. The UI is IMHO very good and reacts quickly. LeCroy also offers free Windows programs (i.e. ScopeExplorer and WaveStudio) as well as other tools which allow you to control the scope remotely and are better than anything I've seen from Rigol or for the low-end Agilents.You could then use the saved money over a new Agilent DSOX3k or LeCroy WaveSurfer 3000 to buy other gear like a USB logic analyzer (which is much more versatile than the integrated decoding functionality in lower class scopes).Certainly worth considering.

author: Mr Simpleton
author_rank: Unknown
timestamp: July 07, 2014, 07:46:37 am
content: You got some really good advices here... still I feel you should really look at second hand market. Beeing interested in RF there are numerous gadgets that are useful, and spending it all on one high end digital scope that will be outdated in a few years sounds not too smart.Why not get a VNWA (sdr-kits) and a Tek 2465, and then a Rigol 2072 if you really need a digital scope? As you do have a spectrum analyzer and a simple digital scope, try to think what you really need, what is limiting you when building your stuff??Building the SSA sounds great fun and should keep you busy a few weeks.. lets us know how your are doing!

author: nctnico
author_rank: Super Contributor
timestamp: July 07, 2014, 10:49:31 am
content: Quote from: QuantumPhys on July 07, 2014, 04:08:29 amTry to talk them out of that idea. There is always a demand for people able to build and/or engineer something no matter how bad the economy gets. Economists and managers on the other hand are a dime a dozen. A good engineering consultant can make more than an economist. Especially with the number of good engineers declining rapidly. I'm steering my kids (which are around your age) towards an engineering career.About the scope: I'm not quite sure whether getting a second hand one is a good choice from a financial perspective. Most general purpose scopes in reasonable condition on Ebay start from $1000 and many sellers are asking too much. For that money you can buy a brand new one although with less bandwidth. If you are into digital circuits as well I'd buy an MSO with digital inputs and make sure it also has I2C/SPI/etc decoding.

author: EEVblog
author_rank: Unknown
timestamp: July 07, 2014, 12:05:06 pm
content: Quote from: nctnico on July 07, 2014, 10:49:31 amYou wouldn't, unless you needed really high bandwidth for not much money.Where the 2nd hand market shines is in terms of RF and more exotic gear. Spectrum analyser, RF sig gens, VNA,s, DSA's etc. Stuff that is still very expensive brand new for good performance.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: July 07, 2014, 12:30:03 pm
content: Quote from: EEVblog on July 07, 2014, 12:05:06 pmI disagree. It might take a bit of patience (ebay is full of overpriced gear where the seller is waiting for that one idiot to buy from him) but for the price of a new low-end scope you can often find a used scope which not only offers higher bandwidth and 4 channels instead of two, and offers much more functionality.Higher bandwidth may or may not be an advantage. Four channels instead of two however is for many applications. And having more than the meagre very basic set of measurement and analysis capabilities that are offered by low end scopes can be a huge advantage, too.

author: con-f-use
author_rank: Unknown
timestamp: July 07, 2014, 12:49:18 pm
content: Please please please don't go into economics! You will be dulled out of your mind and wasting your talent. I'm a physicist and many of my friends work in quantum physics (groups of Rainer Blatt, Peter Zoller, Allain Aspect, Theodor Hänsch and Werner Zeilinger). I constantly hear complaints that students know too little about electronics especially RF design. If you are into electronics, you will find a lot of applications working on things like iron traps and laser optics. You will feel like you actually accomplished something and your life will be happier for it. It would be such a waste to do trivial problems and come up with economic theories that are essentially untestable while constantly working around bullshitting people. Do something fundamental, do something fun.

author: nctnico
author_rank: Super Contributor
timestamp: July 07, 2014, 01:21:46 pm
content: Quote from: Wuerstchenhund on July 07, 2014, 12:30:03 pmShow us an exampleI agree a high bandwidth scope can be bought from Ebay for little money BUT it will need some fixing.

author: MJR
author_rank: Contributor
timestamp: July 07, 2014, 02:51:50 pm
content: Save some of that dough by getting a basic but good scope. That way you will have some cash for what comes next. What is that? I don't know! But I do know that there are many specialized areas in the EE realm and some of them may become more of a passion than hobby. Then you will need the "Flublegrunder 5000" on eBay that is accurate to .005 Flubles at 1tHz. Oh yeah!But seriously, save some. I saved up all summer when I was 13 to buy an HP-41c. $250 at the time. We didn't have any business in our town that sold them, the closest one was about 2 hours away. When we got there I found I was $20 short. I was crushed. My dad said "I really hate to see you spend all your money on a calculator anyway," and I thought I was about to do the un-manly thing right there at the counter. Then he said "let's split it and you can save the rest." What a man! Save some.My career veered from EE long ago. I regret it in a lot of ways. Good luck!

author: QuantumPhys
author_rank: Contributor
timestamp: July 07, 2014, 03:04:59 pm
content: Quote from: EEVblog on July 07, 2014, 04:54:04 amThanks a lot for the advice Sir EEVBlog! Been your student since 2010/2011!I really enjoy hunting for stuff on EBay, and got some good equipment there. But I still feel that I waste way too much time on EBay and books, instead of actually going into the lab and doing something.I will definitely consider a much cheaper scope+other second hand equipment (so glad I moved to US from China recently), but I am still quite interested in the MDO3000. Perhaps I will see your review first?Again, I really appreciate your reply, and your vlog has taught me a tremendous amount of things!

author: QuantumPhys
author_rank: Contributor
timestamp: July 07, 2014, 03:05:58 pm
content: Quote from: cleaningOut on July 07, 2014, 07:12:51 amThanks for helping me say that.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: July 07, 2014, 03:11:45 pm
content: Quote from: nctnico on July 07, 2014, 01:21:46 pmWell, for example I bought a Waverunner 2 LT264M (350MHz 4Ch with 1GS/s on all channels) with most options enabled for the price of a Rigol DS1074Z-S.I also bought a Waverunner 64Xi (600Mhz 4Ch 10GS/s, 12.1MPt/Ch) for less than the price of a Siglent SDS2304.The LT264M is already a huge step from the low-end Rigol, and the 64Xi is so far ahead of the SDS2304 in terms of capabilities and performance that it's not even funny.Both scopes will very likely provide excellent service for the next decade, and if not then either I fix it myself (schematics are generally available, unlike for most low-end scopes), it's replaced by another 2nd hand scope or if it's worth it getting fixed by LeCroy (which especially for midrange and highend scopes does offer some surprisingly good conditions for repair).QuoteNope, it doesn't. In fact, most of the scopes I bought on ebay were fully functional and some even in new-like condition.Of course the majority on ebay is overpriced crap from (mostly business, mostly US) sellers that have no understanding of the market and think just because a device did once cost $50k that they can charge $5k for it ten years later. As I said, they are just waiting for the one idiot that pays asking price. But all that's needed to find the good deals is a bit of patience, and the willingness to consider global sellers (I got some really good deals from Asia).

author: QuantumPhys
author_rank: Contributor
timestamp: July 07, 2014, 03:14:06 pm
content: Quote from: con-f-use on July 07, 2014, 12:49:18 pmI really admire those who do fundamental physics, and I do aspire to be a quantum physicist! Maybe I am still to young to have a clear mind of my future career, and I am just following my interests and instincts now. I hope that they will land me in a field I truly love and enjoy. Thanks for pointing my direction, and I feel really honored to talk to someone like you!

author: QuantumPhys
author_rank: Contributor
timestamp: July 07, 2014, 03:22:12 pm
content: Just been on EBay for one hour. Wondering if a $1500 Waverunner 2 (500MHz 4Gsa/s) is considered a good deal?

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: July 07, 2014, 03:54:39 pm
content: Hi,Remember to leave some money to buy some probes. 500 MHz probes can be expensive.Regards,Jay_Diddy_B

author: nctnico
author_rank: Super Contributor
timestamp: July 07, 2014, 03:59:09 pm
content: Quote from: Wuerstchenhund on July 07, 2014, 03:11:45 pmI'm missing peak detect on these scopes...

author: idpromnut
author_rank: Unknown
timestamp: July 07, 2014, 05:18:43 pm
content: Quote from: QuantumPhys on July 07, 2014, 03:04:59 pmEmphasis mine. I offer this "advice": go outside, look around you (and LOOK), find something, anything, that you are curious about experimenting with, don't understand or plain just think you can make better and GET IN THE LAB AND DO IT!Then see what equipment you're missing and buy it!Gear can be an end unto itself (especially for hobbyists, myself included), but you said it there. Get in the lab and build something

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: July 07, 2014, 05:31:09 pm
content: Quote from: nctnico on July 07, 2014, 03:59:09 pmNot sure why you bring this up again, but LeCroy had Peak Detect since the golden days of their 9300 Series.http://www.thefreelibrary.com/LECROY+ANNOUNCES+A+NEW+FAMILY+OF+FOUR+HIGH+PERFORMANCE+1+GHZ+DIGITAL...-a018242359"Innovative Peak-detect CircuitPeak-detect is a common feature among high-end DSO's, because it allows them to show fast phenomena that might otherwise be missed due to undersampling. One undesirable effect of most Peak-detect systems, however, is a severe loss of horizontal (time) precision. This happens because detected peaks are known to have occurred during a certain interval, but the specific time at which they occurred is not known. Signals acquired with other manufacturers' Peak-detect techniques therefore may not be successfully used for further analysis or processing.LeCroy solves this problem by maintaining both Peak-detected and normally sampled waveforms for each signal. So the user gets all the benefits of Peak-detection without any loss of time precision. LeCroy is still the only scope manufacturer to use this innovative technique. "This was 1996 btw. Not all 9300 Series scopes did have that, though. But that was then.In later the above Peak Detect functionality was removed (only WaveJet has it but its not a 'true' LeCroy scope but an Iwastu), but all Waverunner (and larger) Series scopes (which are much newer than the 9300 Series) starting with the original Waverunner 1 from 1999 can still do something like Peak Detect (via the Extrema math functionality).

author: nctnico
author_rank: Super Contributor
timestamp: July 07, 2014, 05:47:35 pm
content: I asked because peak-detect is not mentioned in the datasheets from the scopes you mentioned. In general (IOW: not Lecroy specific) peak-detect isn't as standard as you'd expect. IMHO peak-detect is a very important -can't live without- feature of a digital scope.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: July 07, 2014, 05:59:12 pm
content: Quote from: QuantumPhys on July 07, 2014, 03:22:12 pmIf it's in good condition, then yes. The scope itself is great, the Waverunner 2 Series was manufactured by Iwatsu (it's designed by LeCroy) and is built like a tank. RAM can be expanded to 512MB (SDRAM PC133), and there are various software options available which expand the capabilities even more.I have put the datasheet for the Waverunner 2 online:http://www.filedropper.com/lecroywaverunner2-2004

author: Neganur
author_rank: Unknown
timestamp: July 07, 2014, 06:40:17 pm
content: lots of good opinions here already.The Scotty's spectrum analyzer (or vna) will serve you well enough for years to come, no need to go buy kit from ebay since you're building that one already, and you learn tons of stuff long time before you see it in the uni.Speaking of uni, I don't think it is a good thing to study something one's parents want you to study*. The years of the young life are too short to waste them on something that does not truly interest you, so I'd recommend to have that in mind once you're at an age where you think about studying. After all, it is you who will have to either work in that profession (whatever it is) or go through the trouble of a career change at a later point in life. Not that that is a bad thing, but it is always easier while you are still young.*: I meant, just to study something because someone else wants you to.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: July 08, 2014, 05:28:33 pm
content: Quote from: nctnico on July 07, 2014, 05:47:35 pmPD functionality is available via the Extrema math function (which does more than PD). PD by name has disappeared after the 9300 Series, as it was no longer considered useful.And newer LeCroy scopes offer WaveScan which makes finding even rare glitches very easy.QuoteThis doesn't surprise me, in modern times when scopes come with large memories the value of Peak Detect is probably questionable.QuoteWhy? I really can't think of any application where PD would make a real difference, unless you have a scope with 8kP memory or so.

author: nctnico
author_rank: Super Contributor
timestamp: July 08, 2014, 05:37:19 pm
content: If you try to measure small pulses with a low repetition rate you'll quickly discover that peak detect is invaluable.

author: Electronics-Repairman
author_rank: Contributor
timestamp: July 08, 2014, 05:56:14 pm
content: What I find really refreshing and I don't think anyones mentioned it, This kid has actually saved up the money for gear, and not getting mum & dad to maybe a loan on it , so well done, for saving up for what ever you end up with, all these different views on what you should buy, i'd personally, sit down with mum & dad see what they think at 14 don't be in a hurry or get swept up with the noise of the forums, take a step back for a while and make a decision on what you want to do.just read my post I'm a Dad sounding like my Dad

author: free_electron
author_rank: Super Contributor
timestamp: July 08, 2014, 06:38:54 pm
content: of course his parents don't want him to be an EE. They want him to become an APP writer. Or a potato salad peddler on kickstarter.Those make as much as an EE , except they do it in 1 day ...what has the world become toI am going to buy a remote tropical island, build me a secret lab there and the rest of the world can go to hell. There is no hope for the human race.

author: djacobow
author_rank: Super Contributor
timestamp: July 08, 2014, 06:46:39 pm
content: It's funny, but it's not funny. I am more and more of the opinion that the days for EE to be a solid, stable, reasonably well-paying profession in the West are over. There will always be jobs for superstars, but the bottom 3/4 of each class of EEs from State U EE programs ... it's just not looking that great.I think the trend to bullshit "apps" and all the current highly valued crap on the Internet will reverse, but I don't think that means great times for Real Engineers are coming back.Quote from: free_electron on July 08, 2014, 06:38:54 pm

author: G0HZU
author_rank: Super Contributor
timestamp: July 08, 2014, 06:57:22 pm
content: QuoteAs an RF designer of about 25 years' experience I'm very impressed with what you are doing at such a young ageBut (as an RF eng) I don't really like much of your current test gear listed below if you like to do RF stuff in the GHz region.QuoteMy advice below is basically what I would do if I were you...Agilent U1272AKeithley 5 1/2 digit meterMy advice would be to sell these:Tek 491 Microwave Spectrum AnalyzerTry and sell this hideous old analyser if anyone will buy it.HP Power SupplyIf it's a decent/expensive HP supply then I'd sell this PSU too and buy a few cheaper TTI onesThen use the money to buy some old school signal generators and an old but very cheap (and very good!) RF power meter (eg HP431C/478A or HP432/478A). Also buy/make various support components like attenuators, adaptors, couplers, combiners, detectors etc.I'm not sure how you have managed to test your RF projects (reliably) without a decent signal generator but if I were you I would also apply to Analog Devices and Hittite to see if you can get free eval PCBs for their various DDS and VCO devices in the GHz region. Also try and get a free eval PCB for the ADF4351. These can all act as useful and small/cheap signal sources up to many GHz and they can be powered/controlled from a laptop via USB.Project suggestion?If you can design a decent downconverter then try and design one for the Rigol DSA815 to allow its many users to look at the 2.4GHz and 5.6GHz wifi bands with their 1.5GHz Rigols. I can design something like this very easily (bit boring for me though as I've designed loads of downconverters in my career) but if you do it and you do it on some kind of blog then you might evenfind a test equipment manufacturer to sponsor you and/or donate you some RF test gear.I'm a bit mystified as to why you want a high end DSO (as your next priority) if you have decided that you like to do RF stuff in the GHz region. I suppose I'd like one too but I really can't justify the space it would use up on my bench/shelf. If I did buy one it would have to be small and easy to move around and above all quiet with little or no fan noise.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: July 08, 2014, 08:00:37 pm
content: Quote from: nctnico on July 08, 2014, 05:37:19 pmI never had a problem measuring LPRF pulses, there are various ways to do this even with older LeCroy scopes (i.e. segmented memory, deviation trigger) without the need for PD.I've last used PD over ten years ago, but this was on a low memory Tek scope, and only on a few rare occasions.Do you have a specific example (test case) where PD would provide an essential advantage with a modern day scope?

author: Hydrawerk
author_rank: Super Contributor
timestamp: July 08, 2014, 08:08:20 pm
content: Quote from: QuantumPhys on July 07, 2014, 02:08:07 amIf you really have enough money, buy Agilent DSOX3000, because it is easy to operate. But remember that you might need to pay extra money for that software licenses...I would not buy that LeCroy-Siglent scope.

author: nctnico
author_rank: Super Contributor
timestamp: July 09, 2014, 01:16:05 am
content: Quote from: Wuerstchenhund on July 08, 2014, 08:00:37 pmVertical sync pulses for example. Yes, TFT screens still use these. I'm using peak detect all the time to look for spikes, noise, spurious signals, etc.

author: JuiceKing
author_rank: Regular Contributor
timestamp: July 09, 2014, 02:29:02 am
content: Quote from: QuantumPhys on July 07, 2014, 02:08:07 amNo!!!! The reason you feel it's unethical is because it's fundamentally wrong for a person your age to be settling down for a life burdened by material goods when you should be free to explore the world. Listen to your conscience!Are you near universities or research labs? Just march right in and tell them what you want to do. Someone will take you under his wing and not only let you play with the gear but will be your mentor and give you insight and life lessons. Just ask...people love to do this.

author: QuantumPhys
author_rank: Contributor
timestamp: July 09, 2014, 04:41:42 am
content: Quote from: G0HZU on July 08, 2014, 06:57:22 pmThanks for the suggestions! Just started out in RF end of last year so what I am doing is still very basic. Indeed, I cannot test my stuff properly as I do not have much gear and I am still looking for a suitable signal generator. The reason I need a scope is actually because 1)I cannot stand my Rigol 2)I still sometimes do analog/digital stuff, and I though that it would still sometimes be helpful for RF work.As for the Tek 491, yes it is rather unusable, but I was very curious how they got up to 40GHz in 1969 so I got one for $110. It would be a piece of Tek history anyways.I will definitely consider building a downconverter for the low frequency analyzers, but I need to be sure of what I am doing first (get a good foundation) before I try to embarrass myself with a poor design online!

author: pickle9000
author_rank: Super Contributor
timestamp: July 09, 2014, 05:24:24 am
content: @QuantumPhysJust reading your tagline, the last bit of equipment is really the best you own (my eyes). Two thumbs up for that one.Of course your nose can come in pretty handy at times too.

author: QuantumPhys
author_rank: Contributor
timestamp: July 09, 2014, 06:33:11 am
content: Quote from: pickle9000 on July 09, 2014, 05:24:24 amAdded! They are 2000 vintage, but still work quite well!

author: pickle9000
author_rank: Super Contributor
timestamp: July 09, 2014, 06:45:19 am
content: Mines a great deal older than yours but can still detect "Magic Smoke".

author: MrsR
author_rank: Regular Contributor
timestamp: July 09, 2014, 07:46:52 am
content: Dave gives pretty good advice, He helped me out and he was right, Although I wish he had answered my last question.I would go around the local workshops and don't forget the Airport as they may have RADAR Engineers there ask look try their gear you will be surprised how much they will help you if you let them and don't be a know it all. Just ask for help and they will go out of their way to assist you. MSO would be better than a DSO, we have computers for holding information. You will need a Signal or function Generator as much as a Scope and other Gear will be needed power supplies multimeters ESRs, LCRs. don't be blinded by one ultimate bit of gear as you will find that other thing is needed just as bad.I have been telling my son these things and now that he is 26 he said I wish I had listened to you mum.That was yesterday LOL.May be Dave can teach you to dumpster diveThere has been a lot of advice some good some really good, so sit back take it in, make a list then sit back again and work out just what you need not want.REMEMBER HAVE FUNRachaelPS. just get the best lot of gear you can afford. and no I'm going to win Lotto next

author: David Hess
author_rank: Super Contributor
timestamp: July 09, 2014, 03:10:00 pm
content: Quote from: Wuerstchenhund on July 08, 2014, 08:00:37 pmOften I use peak detect as an sanity check for spurious oscillations and glitches which would tend to be aliased at low time/div settings. A long record length would help but is not as unambiguous. Even an acquisition record length orders of magnitude longer than the display record will limit sample rates at slow time/div settings.DPO style oscilloscopes may do even better by generating a histogram during acquisition allowing a graded display record instead of an envelope.Another advantage over a long record length is that peak detection (or a DPO histogram) operates during acquisition so it need not slow down the waveform acquisition rate do to processing long acquisition record for display. Even modern and expensive Tektronix MSO/DPO 5000 series oscilloscopes suffers from this.A long record length and segmented memory are indispensable when needed of course so why settle for some when you can have them all?

author: David Hess
author_rank: Super Contributor
timestamp: July 09, 2014, 03:17:36 pm
content: Besides the advantage of performance for a given cost, there is a lot to be learned by refurbishing used test equipment assuming service documentation is available.If I were buying a new oscilloscope, I would look for a lower end model that includes DPO functionality like a Tektronix MSO2000 or MSO3000 or their equivalents made by other manufacturers.

author: jpb
author_rank: Super Contributor
timestamp: July 09, 2014, 03:31:13 pm
content: Quote from: QuantumPhys on July 07, 2014, 04:08:29 amThis is off topic, but as I teach Quantum Computation as part of Computer Science I thought I'd make a couple of comments.Quantum computation falls into the theory and practice.The main theory is based on quantum gates and involves some really clever and fun algorithms but is really mainly maths with a little physics - this is the stuff I teach.The practical side falls into two camps - one is people trying to build quantum gates which is mainly quantum physics/optics/very cold electrons and the other is D-wave who have produced a quantum computer which doesn't take the quantum gate approach at all and is more like a quantum version of an analogue computer. The D-wave computer is rather controversial as people can't agree as to whether it really works in a quantum way at all. (http://www.dwavesys.com)Though quantum computers/computing is fun and may be the future I wouldn't advise it as an end goal. Go into physics if that interests you and you may find yourself doing research into quantum computers. On the electronics side there isn't much in the way of connection between quantum computation and the sort of electronics you currently do.

author: Hydrawerk
author_rank: Super Contributor
timestamp: July 09, 2014, 04:51:17 pm
content: No, Tektronix MSO2000 is an obsolete product from 2008. The specs are rather poor. No Trigger output. A low resolution screen.

author: David Hess
author_rank: Super Contributor
timestamp: July 09, 2014, 08:55:08 pm
content: Quote from: Hydrawerk on July 09, 2014, 04:51:17 pmThe MSO2000 is just an example of what I would look for.About the only feature I could really take advantage of in a new oscilloscope is phase/magnitude FFT.

author: Rigby
author_rank: Super Contributor
timestamp: July 10, 2014, 01:42:14 pm
content: Quote from: free_electron on July 08, 2014, 06:38:54 pmAnyone that's doing something for the money is doing it for the wrong reason. Period. I don't care what it is, or what they money is, it's the wrong reason.Besides, everyone knows, or has plenty of evidence to conclude correctly, that those closest to the money get the greatest share. Engineers are not at all close to the customer, therefore they are not at all close to the high incomes. Sales and distribution is where the money is. Company leadership. Lawyers. The closer you are to the point where money changes hands, the larger your share of the money will be.The truth of it is that CEOs, CFOs, CIOs, CTOs, customers, sales, virtually everyone except engineers put engineering at the bottom of the pile of importance. That doesn't mean that engineers are the least important, it means that engineers are perceived as being one of the least important parts of a company. If you don't believe me, then compare an engineer's salary to that of a small town animal control officer. They're about the same, except in cases like free_electron, where he's someone who is vetted and trusted, and even he makes less than the mayor of the small town I grew up in with a population of 2500.The amount of money you will earn is highly dependent on how difficult it will be to replace you, and how close you are to the money.