Oscilloscpe purchase

An o'scope is an investment -- although you don't need to invest $20K in one -- and any one of the TDS scopes would be a good choice. I've had a TDS220 for years as a "home" scope and it's great.

PC-based o'scopes are no comparison to the little Tek scopes BUT you can do quite well for a PC-based logic analyzer. My favorite is a relative newcomer to the field, the LogicPort. Info (with demo software) at

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Rich Webb   Norfolk, VA

Go buy one at DSE or Jaycar, since you say you want to grow out of it in a few months :-). For a starter one of such would serve you quite a while while you save up for the logic analyser which would be a serious outlay !!

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Regards ......... Rheilly Phoull

Hi, Jon. I'm hearing you say you want to buy a new scope. I'd try to beg or buy a used one first -- you should ask around. There's probably a good working scope sitting idle in someone's basement in your neighborhood. Ask around, particularly for older TV/Radio repair guys.

But it might be best for you to buy new at this point, because it sounds like you'd be more comfortable with something new, and also you don't have the electronics background to be repairing things just yet.

About 20 years ago, my scope got lost in baggage, and I just needed something to do a service call on a machine. I bought a low-end 40MHz dual trace Gold Star (now known as EZ Digital) analog scope. I've still got it as a spare (it's a little big for service calls), and it still works fine. I've had to repair it once (my fault).

EZ Digital makes a number of good, reliable analog dual trace starter scopes. I would be looking at the OS5XXX, with the choice depending on your price range. Any of them would be a good first scope, but the more you spend, the more capabilities you have. The OS5030 is a 30 MHz dual trace analog that's available for less than $400 new from at least one source. If you're feeling a little more free with the bucks, the OS5040 is a 40MHz scope with delay (you can usually cobble together a delayed external trigger circuit if you really have to on the OS5030), and is available for less than $600. Either one would be a good choice. I'd pick the OS5030 myself.

If you've got a budget of $1000, you can buy either of these scopes, buy a couple of linear power supplies for your bench and a good DMM, along with a good soldering iron and a protoboard, and spend the rest on whatever you can find at the hamfests that are coming along. You'll be "good to go".

If you spend a lot of time in electronics, you'll probably eventually need another scope. But you'd be amazed at how seldom you actually have to have a digital storage scope. A 30 MHz scope will show something on the CRT at frequencies far above that, and "something" is frequently all you need.

Just don't get one of those multi-function scopes with all kinds of other gadgets built in. They're a pain to fix.

Good luck Chris

They seem to be a decent outfit, and carry a number of Tek 'scopes like the 465.

Ed

Too bad, ebay is a great place to buy. There is no reason why you cant bid for a scope thats local to your location then you can go round and inspect it yourself.

You'll need a lot more than 1Mhz, I wouldn't look at anything less than

60Mhz.

Agilent (HP) do a mixed signal scope, 2 analoge channels plus 16 digital, don't get the earlier version if you do alot of slow speed work.

"Abstract Dissonance"

** One like this will give you a lot of test equipment mileage for very few dollars.

....... Phil

Why not? Some excellent deals are to be had on eBay, and many companies selling them on there are legitiment test equipment refurbishers and will provide a warranty and guarantee it's performance etc.

Start out small and work your way up. Only then will you know what your true requirements are.

That is OK for the money, but read my notes below. You'll want a real analog scope too.

Agilent do the only decent "mixed-signal" (scope+logic analyser) scope on the market, but it's well out of your price range.

Get a used one, you'll save real $$$ and get a higher performance unit for the price.

Seriously, get over it :->

There are plenty of 2nd hand test equipment suppliers around, and many of them now sell on eBay as well. If you are US based then you are spoiled for choice. Even here in Australia we have a cople of 2nd hand scope dealers, the US seemingly has hundreds. I have heard people in the US buying scopes by the pallet load!

Here is what you need to do:

1) *essential* - Buy a cheap 2nd hand analog oscilloscope (20MHz will do for starters, but a 100MHz one would be nice). New analog scopes of any decent bandwidth offer poor value for money to someone in your position.

2) Buy a new PC based USB logic analyser/scope. BitScope is one such example, but there are plenty around now, just check the ads in magazines like Circuit Cellar. They cost several hundred dollars upwards. It will give you a logic analyser as well as a digital storage scope and spectum analyser. The sample memory it has the better. A few KB sucks, 32KB is useful, several hundred KB to a MB is great. More memory allow you to zoom in to see packets of digital data etc - very handy.

Dave :)

I forgot to add *why* you need a higher bandwidth analog scope like

100MHz+... If you are viewing digital signals (or anything other than a sinusoidal wave), a 20MHz scope *won't* display any detail in a 20MHz signal, so it can become quite limiting for anything but "seeing if a signal is there or not" at those sorts of frequencies.

Dave :)

Blah, blah, blah... Analog scopes suck. If analog scopes were so good, why don't Agilent, Tektronix, LeCroy, or any of the real scope manufacturers still make them? You, like many, are confusing sampling rate and bandwidth.

First, you are making the mistaken assertion that sampling rate is twice the bandwidth, and hence if you are using a 20MHz scope, you will not see more than 2 points per period. This simply isn't true. Many scopes that can't achieve very high sample rates, will use equivalent time sampling to sample the same signal repeatedly with slight time offsets achieving quite good resolution.

Second, if you have a 20MHz scope that means the bandwidth of the scope is

20MHz. Signals that are greater than 20MHz will be rolled off, so a 20MHz square wave will look like a sine wave or closer to it than square to begin with and this applies to both analog and digital scopes.

Digital scopes and analog scopes each have respective advantages. However, analog scopes advantages are only advantages when compared against crappy low-end or ancient digital scopes. Modern (good quality) digital scopes will readily outperform any 100MHz analog scope, let alone a 20MHz scope at virtually all applications. In some cases, where you are concerned about glitches, complicated triggering patterns, and one shots, there simply is no substitute for a digital scope. Digital scopes can also provide better persistence features, FFTs, frequency measurements, etc.

"blah" = another Yank compewter geek f****it

** Digital scopes suck big time - for nearly all analogue work. ** For the bloody obvious reason Asian scope makers beat them hollow on price. ** Absolute BULLSHIT.

........ Phil

It is because the asian manufactuers can make them at a lower price. There probably isn't enough margin in it for the big names any more.

I am not confusing anything. I know all about sample rate, bandwidth, equivalent time sampling etc. I have designed several DSOs over the years thank you very much.

I know this, and I said nothing about about DSO's and their sample rates!

Most scope manufactuers are going away from equivalent time sampling becuase it sucks, they are all going real-time with deep memories, with the sample rate at 10+ times the bandwidth. Only the crap very low end digital scopes and the extremely high end bandwidth scopes use equivalent time sampling these days. The crap ones do it because it's cheap, and the high end ones do it because they have no choice. You'd be silly to buy say a 100MHz DSO with 20MS/s sample rate working in equivalent time. Real-time is the way to go for a general purpose low to medium bandwidth DSO.

Equivalent time scopes are of course next to useless for single shot work.

Of course it does, I did not say anything to the contrary.

Exactly!, and that is what we are talking about. The OP can't afford anyting but the crappiest low end DSO with a few KB of memory and the response time of a snail.

Yes, modern DSOs like the Agilent 6000 series are brilliant. Can the OP afford one? - No.

Of course. But the OP has a total budget of $1000 and wants a logic analyser too, you recon he should blow it on the crapiest low end DSO he can get? He would be *much* better served by a nice 100MHz analog scope for repetative work and a PC based DSO/logic anlyser for single shot work. He'd likely still have change from his $1000 too.

Dave :)

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Like you\'ve got someone in Oz who\'s building world class scopes?

"John Fields"

" John Fields Professional Bullshit Artist "

** The psycho Texas jerk off is not even good at that.

........ Phil

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Geez, Phil, you\'ve turned into a one-trick pony!-)

John Fields"

" John Fields Professional Bullshit Artist "

** The f****it, psychotic Texas jerk off is not even good at that.

........ Phil

It looks like that Austrailian parrot is stuck again. Will someone down under please rattle his cage? ;-)

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

I'm still not quite sure what to do.

looking on ebay I see many logic analyzers for under $100 such as

HP 1650A Logic Analyzer(40$) HP 5000A Logic Analyzer Bitscope USB 100MHz oscilloscope, logic analyzer, & AWG(100$) Tektronix 3001GPX Logic Analyzer w/opt 1M & P6490 Probe HP(HEWLETT PACKARD) 1672E LOGIC ANALYZER 68 CHANNELS(229$)

and some oscilliscopes such as

Tektronix 465 2Ch 100MHz Oscilloscope !!!(50$) TEKTRONIX 465/OSCILLOSCOPE TEKTRONIX 2236 OSCILLOSCOPE Agilent / HP 54112D 100 MHz Digitizing Oscilloscope(100$) TEKTRONIX MODEL 2235 100 MHZ DUAL TRACE OSCILLOSCOPE(160$)

Tektronix 2465 Oscilloscope 300MHz(200$) (the prices are in ascending order)

Are any of these good deals?(i.e., good equipment for the money and will get me on my way?) My main concern with ebay is not getting ripped off and not getting something that is broken. I've heard way to many horror stories about ebay and thats the main reason I'm trying to avoid them.

HP 8165A Programmable Signal Generator, 1 mHz-10MHz(75$) WAVETEK 2410 SIGNAL GENERATOR 10KHZ-1100MHZ(100$)

The link to the wavetek... it says something about fail on the calibration table and things like this make me worry about buying something that its just going to end up giving me a headache and knows what else is wrong with it. When someone says "It powers up and everything seems to work but *I have no way of testing it*" it makes me wonder if they are trying to sell a piece of crap.

Is there any reputable stores in the US that handle used equipment like this that has a website? (maybe even one that you yourself have experience with ;) I don't mind paying a little bit more so that I know that I'm getting something that works.

Thanks, Jon

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[snip...snip...]

A couple of places that have refurbished test equipment that have had me on their catalog mailing list for several years:

And one that's (AFAIK) only new and not refurb:

I've bought a few things from TEquipment.net, have had no problems, and will probably look there first when it's time for another purchase. Haven't used the other two but AFAIK they are okay.

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Rich Webb   Norfolk, VA

Thanks.... Some of the used stuff seems a little expensive(cheapest I saw was 500$) but atleast its a start.

Jon