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eHam Forums => Elmers => Topic started by: KG4CLD on October 29, 2012, 01:13:59 AM



Title: Oscilloscopes!
Post by: KG4CLD on October 29, 2012, 01:13:59 AM
Hello, my name is David. I am interested in learning how to use an oscilloscope.  I would like to purchase a used one, however I don't know which type or model to buy? Which features are common and which are just not needed? Analog or digital?  20 MHz, 60 MHz, 100 MHz? Single or dual trace?  I have some electronics understanding, however I've never used an oscilloscope.  I recently purchased a few books and computer CD's which I think would help teach me a little about oscilloscopes, but with all the models out there, both new and used, I don't know which to chose from.
Also, perhaps you could recommend which types of test probe and other accessories would be good.  Any help would be appreciated.  I can be contacted via my email: dgs386@yahoo.com

Thank you,
David-KG4CLD


Title: RE: Oscilloscopes!
Post by: KA4POL on October 29, 2012, 04:01:14 AM
You'll see there will be lots of different recommendations on your questions. It depends of course on the planned use. If you are planning to use the oscilloscope for RF you only need to go up to about 60MHz. Dual trace is good for comparing input with output, like an audio amplifier.
I'd shop for an oscilloscope like a used Tektronix. You get a scope with better or wider specs than buying a new one. Digital may be fine but really not needed.
The oscilloscope is a very useful measuring equipment. You'll find lots of information searching the web.


Title: RE: Oscilloscopes!
Post by: G7MRV on October 29, 2012, 04:16:33 AM
I'd echo KA4POLs advice, look for a used 60MHz (100 if you can find one cheap), dual trace. If it has an X input thats a bonus (you wont use it much, but learning about 'scopes you'll hear about Lissajous figures, and you need the X input to make them).

You dont need digital, nor do you need a storage scope (although they are nice to have, unless your looking at fast, single shot waveforms its not worth the extra cost)

Theres a book by Babani publications called 'How to use oscilloscopes and other test equipment', written by RA Penfold, you'll find that available cheap, and it will tell you all you need to know to get started.

My 'scope is a 20MHz dual trace Hitachi V-212, and im about to start servicing it as its playing up badly!


Title: RE: Oscilloscopes!
Post by: K0OD on October 29, 2012, 04:48:25 AM
There are a number of excellent scope tutorials on Youtube. Some are ham oriented.  


Title: RE: Oscilloscopes!
Post by: WN2C on October 29, 2012, 08:45:48 AM
Go to Tektronix web site for some tutorials. Tektronix makes and has made some very good scopes.

de wn2c  Rick


Title: RE: Oscilloscopes!
Post by: G8JNJ on October 29, 2012, 09:26:26 AM
Hi,

If you have a PC with a sound card and want to play with a basic audio frequency scope.

Try downloading the free version of http://www.zeitnitz.de/Christian/scope_en

I've used it to teach the basics to engineering teams with good success.

Connect your soundcard speaker out to line input and you can take a look at various combinations of waveforms produced by the audio generator that forms part of the software application.

You can try mixing audio signals with different waveshapes and also take a look at the distribution of harmonic components with the built in spectrum analyser.

Regards,

Martin - G8JNJ

www.g8jnj.webs.com




Title: RE: Oscilloscopes!
Post by: G3RZP on October 29, 2012, 12:03:15 PM
Be a bit careful with digital 'scopes. You can get strange aliasing effects which you don't get with an analog 'scope. A good test with a digital 'scope is to go to about one half of its nominal frequency e.g for a 100 MHz 'scope,  display a 50 MHz signal  modulated with 1 kHz to a depth of 90%. See how many possible displays you can get.

I'd go for a solid state second hand Tektronix, something like a 465 or 475.  You want a set of x1 and x10 probes, too.


Title: RE: Oscilloscopes!
Post by: AC5UP on October 29, 2012, 02:50:25 PM
I'd go for a solid state second hand Tektronix, something like a 465 or 475.

Excellent advice, but do you realize those 'scopes are pushing 30 years old?  Nothing wrong with being 30, especially if it's the girlfriend, but at that age the odds of scoring a totally healthy specimen grows less likely by the day... And nothing can jerk a 'noob around like a first 'scope that ain't quite right.  :(

I say this because I have a Tek 475A that needs work (likely a new electrolytic in the power supply) and I also have one of these: http://www.ebay.com/itm/Tektronix-2213A-60-Mhz-Dual-Trace-Oscilloscope-/370669543925?pt=BI_Oscilloscopes&hash=item564da061f5 (http://www.ebay.com/itm/Tektronix-2213A-60-Mhz-Dual-Trace-Oscilloscope-/370669543925?pt=BI_Oscilloscopes&hash=item564da061f5)

The 475A is waiting for The Golden Screwdriver to arrive, the 2213A is the one that gets used regularly because it's fast, stable, and very easy to work with. Also has a trigger circuit that can't be beat. I have better boxes available (like a 7844 dual gun jobbie) but the 2213A is the one I like.   ;)


Title: RE: Oscilloscopes!
Post by: KB5UBI on October 29, 2012, 03:10:38 PM
I've had a Tektronix 453 (60 MHZ) for about 40 years and it's still working well. Last year, I purchased a 100 MHZ Rigol and I am impressed. The newer digital scopes do offer some extra features over the older analog scopes, such as display storage, math functions, and frequency / spectrum displays but out of habit, I still use the old Tek sometimes.

Which ever way you go, make sure you get a dual trace with delayed sweep (analog). IMO, a sound card scope will never replace a discrete scope.


Title: RE: Oscilloscopes!
Post by: K8AXW on October 29, 2012, 08:15:32 PM
Rather than give you my opinion to add to the infinite number of opinions you'll be receiving, let me offer this link.  It is a Google search result for "Youtube how to use an oscilloscope."

Some of these are very interesting to watch while you wrestle with the decision on which one to buy and then after you do buy one, how to use it.  Rotsa Ruck!

73

Al - K8AXW


http://www.google.com/search?q=youtube+how+to+use+an+oscilloscope&sourceid=ie7&rls=com.microsoft:en-US&ie=utf8&oe=utf8


Title: RE: Oscilloscopes!
Post by: G3RZP on October 30, 2012, 04:34:01 AM
I have a 30 year old 20 MHz Hameg: good scope within its limitations. It did have to have a new power transformer at one time, though.


Title: RE: Oscilloscopes!
Post by: K0IZ on October 30, 2012, 04:40:54 AM
I have a Tektronix 2465B dual 400Mhz scope that I purchased several years ago for about $250.  Super scope.  Most any of the Tektronix scopes would be good.  However they all use proprietary solid state devices that are not available.  So if something fails, it is highly likely that the scope is unrepairable.  I have seen some new scopes (from China) for sale, in the range of $100 to $150.  Don't have any experience with them, but the specs look rather good.

Re probes, you can get a couple of 100Mhz probes on eBay for about $10.  I have these and they work great.  400Mhz probes are MUCH more expensive, and not recommended unless you need the extra bandwidth.


Title: RE: Oscilloscopes!
Post by: KG4CLD on October 31, 2012, 06:41:23 PM
Thank you to all who offered me advice and insight into the types of oscilloscopes and probes. You gentlemen have given me a better grip on what to look for and I want you to know that I am grateful for your help.  Again, thank you!


Title: RE: Oscilloscopes!
Post by: K7MH on November 03, 2012, 12:02:30 PM
A little late here maybe but...
There are a zillion Tek 465(B) series scopes out there. You can find them for around $150 give or take. Sometimes with a good probe or two.
Around here there are always a couple of them on Craigslist for sale along with several others. That is where I got mine with 3 probes and the DM44 multimeter for $100. If you buy one locally, the seller can show you that it works ok. For most ham radio related use it may be all the scope you ever need.

A pretty good book about analog scopes is a pocket book size one by R.A. Penfold, "How to Use Oscilloscopes and Other Test Equipment". It is pretty easy reading, only about $5 and can be found on Amazon. It just talks about analog scopes so you don't have to sort out info about digital storage scopes you may not need to know about.

W2AEW has a lot of tutorials on scopes on YouTube that are good to watch. He uses a Tek 465B in many of them.


Title: RE: Oscilloscopes!
Post by: W2AEW on November 04, 2012, 01:48:03 PM
I've got over sixty videos on my YouTube channel.  More than half of them deal with how to use an oscilloscope in one aspect or another.  Some even discuss ham radio applications for oscilloscopes. The most popular video is How to Monitor your Ham Radio Tx with an Oscilloscope, and it's been been viewed over 26,000 times.

My YouTube channel is:
http://www.youtube.com/w2aew (http://www.youtube.com/w2aew)



Title: RE: Oscilloscopes!
Post by: W6REH on November 13, 2012, 07:32:28 PM
The tutorials on youtube from W2AEW are fantastic.

I will agree that the Tek scopes are a good choice. I used both the 456 & 2465 at a company building rf stuff.


Title: RE: Oscilloscopes!
Post by: N4CR on November 13, 2012, 08:40:03 PM
My Tektronix scope was purchased used with some cheap no name probes. They really stunk. I did a little research for the part number that came with the scope, shopped eBay for months until I got two of them NOS one at a time. Paid about $20 each shipped because I was patient. They are like night and day to the cheap ones.

No way would I put the $10 probes on any scope. There might be good ones out there, but the scope was designed around a specific probe to get it's specs.

My experience is that cheap probes perform like cheap probes. I couldn't even get a decent square wave out of the test point regardless of the compensation control.


Title: RE: Oscilloscopes!
Post by: W2AEW on November 14, 2012, 06:27:03 PM
The tutorials on youtube from W2AEW are fantastic.

I will agree that the Tek scopes are a good choice. I used both the 456 & 2465 at a company building rf stuff.

Thanks for the complement!  I find it hard to believe that my YouTube channel is closing in on nearly a quarter million views!

73,
Alan W2AEW


Title: RE: Oscilloscopes!
Post by: K8AXW on November 14, 2012, 09:14:59 PM
Alan:  The reason for the quarter of a million hits for your YouTube videos is easy to understand.  They are the best on the web!  I have your site bookmarked and have spent many hours watching and learning. 

Not to sound like someone blowing smoke up your butt, but the combination of voice, knowledge of the material and fluid presentation makes for a very professional and easy to watch video.

73

Al- K8AXW


Title: RE: Oscilloscopes!
Post by: W2AEW on November 16, 2012, 07:59:52 PM
Alan:  The reason for the quarter of a million hits for your YouTube videos is easy to understand.  They are the best on the web!  I have your site bookmarked and have spent many hours watching and learning. 

Not to sound like someone blowing smoke up your butt, but the combination of voice, knowledge of the material and fluid presentation makes for a very professional and easy to watch video.

73

Al- K8AXW


Thank you very much, Al.  Please let me know if there are any topics that you'd like to see in a future video.
73 de Alan W2AEW