My first oscilloscope

Discussion in 'General Electronics Chat' started by s_mack, Aug 7, 2012.

  1. s_mack

    Thread Starter Member

    Dec 17, 2011
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    hi. Easy question (to ask, maybe not so easy to answer :))

    Should I look to be buying a new Chinese o-scope like a $400 Rigol, etc. A cheaper (but perhaps more functional) mixed-environment tool like the $350 QA100, or take a chance on a used unit like a $200 Tektronix 2246 (no probes, not calibrated, seller says it works "good")?

    - Steven
     
  2. vk6zgo

    Active Member

    Jul 21, 2012
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    If you are going to buy a digital Oscilloscope,I would suggest you go with the Rigol,as even the best PC based 'scopes are a bit lacking compared to a "standalone" instrument.

    As a first Oscilloscope,I feel you may be better off with a secondhand analog unit,as they offer "more bang for the buck".
    Keep in mind that these older units were not made to be sold at around $300,as are modern cheap DSOs,but were professional instruments at around 20-50 times that price,& were built to an appropriate standard.

    Industry has largely gone to digital 'scopes,which leaves these excellent instruments available to the normal hobbyist/student at extremely cheap prices.

    Early generation DSOs are also very cheap,but offer poor performance,compared to their analog contemporaries,or modern digitals such as the Rigol.
     
  3. strantor

    AAC Fanatic!

    Oct 3, 2010
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    I vote tektronix. But I'm biased. I've never used any of those DSO or PC based scopes. I bought a used tektronix on ebay for 200$ and I love it. It's 20 y/o military surplus. It came from a test equipment refurbisher/calibrator/seller, with calibration cert.
    See if you can find one with cal cert from a reputable dealer for the same price. I bet you can.
     
  4. s_mack

    Thread Starter Member

    Dec 17, 2011
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    Well, so far no luck on finding one calibrated even close to the same price. How important is that?
     
  5. BSomer

    Member

    Dec 28, 2011
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    If you can get the service manual for the o-scope you get, you may be able to calibrate it yourself. It may not be as accurate as a professional calibration but will get you by. You will need a function generator to do it though.
     
  6. strantor

    AAC Fanatic!

    Oct 3, 2010
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    Yeah I'm not finding any either. I'm surprised. year before last they were much cheaper. Sorry to have sent you barking up the wrong tree. As far as "how important is certificate of calibration" - Its pretty important to me, at least to have it when you first get the scope. Reason being, I don't know what "tested, OK" means. Does that mean that they turned on the power and some blue lines came up on the screen? It could. But if it says "calibrated, certificate of calibration included" then I know that they followed a procedure and verified that the unit is accurate across a wide range of measurements. If they did this, and everything was within spec, then I can be reasonably sure that it's not a dud.
     
  7. s_mack

    Thread Starter Member

    Dec 17, 2011
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    Certified calibration costs more than the unit!
     
  8. s_mack

    Thread Starter Member

    Dec 17, 2011
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    Then that's more equipment lol. I'm probably better off just going Chinese.
     
  9. BSomer

    Member

    Dec 28, 2011
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    Well... Don't you "need" more equipment anyway? :D
     
  10. MrChips

    Moderator

    Oct 2, 2009
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  11. BSomer

    Member

    Dec 28, 2011
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    Personally I would go with the Rigol DS1052. That is one of the digital scopes I have been looking at getting. I have read quite a few really good reviews about them and very little bad things. For an entry (economy) level DSO the Rigol is one of the best ones available.
     
  12. vk6zgo

    Active Member

    Jul 21, 2012
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    Most people who "go Chinese" discover a new hobby--discussions with other owners on the 'Net about when the next firmware update "that fixes all the bugs" is due out!:D

    Calibration sounds good,but how often do you need it?
    Maybe if you are making something which has to pass a test by a licencing authority,otherwise,the old Tek beasts are pretty close unless there is a real fault,in which case,fix the fault,don't try to "calibrate it out".

    Back in the day,we used to do our own calibration "in house" at work,& had all the equipment & books.
    The Tektronix stuff hardly ever needed tweaking,year after year.
     
  13. MrChips

    Moderator

    Oct 2, 2009
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    I have been using Tek and HP scopes for a very long time and have never had a reason to calibrate a scope.
     
  14. strantor

    AAC Fanatic!

    Oct 3, 2010
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    You guys are absolutely right; these older high end scopes rarely ever need calibration. I was simply suggesting it as safety measure. If it was calibrated before sale, and sold as a "calibrated instrument" then there is no room for any major faults. I have 2 broken tektronics scopes in my garage that would pass the "guaranteed not DOA" AKA "turns on" test. If I wanted to be dishonest, I could sell them as working scopes, just like this one and get away with it. However, I there is no conceivable way that I could sell them as calibrated instruments.
     
  15. s_mack

    Thread Starter Member

    Dec 17, 2011
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    My hangup with the Rigol... and I'm sure I'm being silly (having never used an o-scope before... and still, frankly, a little unsure what its for - just everyone keeps telling me I need one)... is the little crappy screen. Compared to the Owon and others that have nice "big" 800 x 600... or the PC driven ones that then have a nice 30" widescreen (my monitor)... it seems so... umm... tired and broken down for a brand new device.

    so if that's REALLY not important in the least... I suppose I could go the Rigol way since there really are so many good reviews.

    Or I could get that Tek, which apparently was a heck of a machine in its day and its only $200 (but I'd have to get probes - how much are those gonna run me?).

    Lol... considering I'm not even sure what I'm going to be doing with the thing... I don't know if "calibration" even begins to apply.

    - Steven
     
  16. vk6zgo

    Active Member

    Jul 21, 2012
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    I can't understand this fixation people have with big screens--it's not a TV,or a PC Monitor,it's an Oscilloscope!
    Myself & many thousands of others have used analog 'scopes over many years,which have smaller screens than the Rigol,& never growled about it.

    If you have never used an Oscilloscope,I would definitely recommend the Tektronix.
    You will find hundreds of applications for a 'scope,& be amazed that you got along without one for so long.
    After you have found what a 'scope is capable of,you will be better prepared to evaluate DSOs.

    The present generation of DSOs are not the last word,& maybe in a few years,you will be able to afford one which offers better performance than that currently available.
     
  17. s_mack

    Thread Starter Member

    Dec 17, 2011
    187
    5
    It sounds like I touched on a pet peeve of yours (the screen thing) :) As I said, I'm new to this so I don't know what's important and what's not. It would seem to me that if a screen is important at all, that a nice big clear screen would be all the more important.

    Now a pet peeve of mine... the argument that one should "start" somewhere and move up later. Within a particular budget, I am of the mind that you should start where you plan on ending. Wasting money on an inbetween is really just stupid. So if I'm going to spend $200 now and it is inevitable that I am going to have to buy a $400 DSO later, then that means we're up to $600 and that's doubled my budget. This isn't a whimsical thing that you buy for each project, right? If that 1986 Tek is still considered "good" then I should be able to have the expectation that it would be my first and last scope. If a digital is what's required today, then a digital is what I should be looking at. If not, then why would my experience level now vs the future necessitate what I need?

    A child needs to start with a child's bike and get an adult bike later because a) he's going to physically need different sizes and b) he's apt to break the first one. While I may not know what I'm using it for, I don't plan on starting with one I don't need now and getting one I do need later.

    Unless it *IS* likely that I break the first while learning, and then... isn't the answer to get a cheap $100 DSO toy like that one SparkFun sells?

    I'm just saying, that a budget of $300 means a budget of $300, not $200 now and $x later. If I need to spend $x... if that's what is necessary to function with this type of equipment... then I need to save for $x.

    - Steven
     
  18. PackratKing

    Well-Known Member

    Jul 13, 2008
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    I have seen no reference to B&K Precision - for my $$ - they give tektronic a good run for their money.

    I have a B&K 1541A 40 Mhz Dual, that served me flawlessly from 1984 until Digital cameras put me temporarily out of service in 2005............ I covered it and slid it under my bed .
    2010....I finally have enough other bullmanure cleared up, and can resume "playing", so wondered if it's vacation bothered it.
    So I emailed B&K, and asked about local calibration service........and was told it was considered obsolete -- no surprise there.
    Then, since it never hurts to , I asked what literature was available to tune it myself.......
    They sent me component lists, board trace diagrams, component layouts, and a complete calibration regimen.....free ! Aside from major parts like a new CRT, I would imagine that any good quality off-shelf components would serve to refurbish it, like capacitors, etc.........

    B & K Forever !!! :)
     
  19. MrChips

    Moderator

    Oct 2, 2009
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    We've got two threads on the identical subject on the go so I get confused which one I'm on:

    http://forum.allaboutcircuits.com/showthread.php?t=73007

    So you are receiving two opposing views:

    1) Used reliable analog scope such as a Tek 465, 2213 etc.
    Reasons: low cost, reliable, good starter instrument, under $200 on ebay

    2) DSO such as Rigol or OWON.
    Reasons: modern, digital, single event capture. under $300-$400

    I think you should examine the following needs:

    1) How much bandwidth do you need?

    For simple audio testing, 10MHz will do. As you move on to digital work 50MHz to 100MHz will be desired.

    2) What are your applications?

    Simple audio and analog testing, single event capture is not so important.
    Again, for single event and low repetition rates you cannot beat a DSO.

    If cost is your primary criteria, I would go with a used analog scope.
    If you are planning to do digital work, I would get the DSO to allow you to capture single events.

    (On your last post, you may have a budget of $200 now. Five years from now your budget could be $1000. There is still some logic in getting a low cost used instrument now to play with. Later in life you will be better informed to form your own decisions.

    Folks buy starter homes for similar reasons. They may move on to their dream home later in life.)
     
    BSomer likes this.
  20. vk6zgo

    Active Member

    Jul 21, 2012
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    My point was, that in "X" number of years, moderately priced DSOs may be as good as analogs in those aspects where they are lacking at present,while retaining the features where they are already superior.
    Very expensive DSOs are pretty much there now,& hopefully,it will trickle down to the cheaper ones.

    For analog work,including most fault finding,analog 'scopes are easier to use,which is why I tend to recommend them.

    The choice is,obviously yours,but if you really feel you need a DSO,I would suggest that there are many specifications which should take priority over screen size,especially as you can link your Rigol to a PC for a large display if it is really necessary.
     
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