I'd like Oscilloscope

Does anyone have an oscilloscope I can buy? Or know of one that’s on sale? Although I’ll be doing mostly audio frequency stuff later, I’d currently like to see if the Thereminesque things I’m working on right now are actually doing anything, so being able to show things in the RF range is desirable. (Although, trying to use a TTL level IC where a CMOS level one was in the diagram might be the main issue. But anyway.)

Thanks!

PS: A quick introductory course of how to not break it would also be much appreciated!

Joseph, I have two that were given to me and since I moved to Los Angeles they’re sitting in my apartment. You can have the one. I believe it needs fixed. You can just have it.

You’ll need an Oscilloscope to fix it however! :slight_smile:

Bill

I think the trigger needs replaced and it just needs an external one. :smiley:

Unless you want to spend $$$ you’re not gonna find an oscilloscope that shows anything in the RF range. :slight_smile:

You might want to take a poke at the Hive’s current two or three oscilloscopes and see what they show you. I would avoid a broken oscilloscope, depending on what is broken they can be difficult to damn near impossible to fix.

I have an old TV repair scope that’s a little bit dim (and that might be easily fixable with just a trimpot or something) but works otherwise. If you don’t end up going with what shadoxx has, let me know and I’ll get it.

Aw nuts, that’s what I was afraid of. Guess I’ll need to take a look at the Hive one, then.

Out of curiosity, Is there anything about a TV repair scope that’s particularly different compared to whatever a normal oscilloscope is?

It mostly just means that they’re cheap, reasonably solid, mass-produced analog oscilloscopes made mostly for repairing old CRT televisions. This one goes up to 20 MHz (I think), which is into the RF range, but not very far into it. A “normal” oscilloscope nowadays is a digital one.

I think 20 MHz is actually higher than I need, the circuit is supposed to oscillate at only around 4 MHz. I’d certainly like to give it a look, even if I don’t end up needing to use it for that high frequency stuff.

I have a 70Mhz Rigol 4 channel if you need something that fast. There is a 50Mhz Rigol 2 channel at the space on semi-permanent loan. It can be overclocked to 100Mhz but it hasn’t been modified yet as it’s still in warranty.
-D

Sounds like you are getting to learn about oscilloscopes. :grinning:
First you need to be clear on your requirements; channels (2 or 4), bandwidth (20, 50, 70, 100 MHz), mixed ( do you need logic analyzer).
Then you get to look at quality. Do you need “professional” (Tektronix) or hobby (Rigol).
Be very careful on the Ebay stuff as you can’t verify the condition.

I did a bunch of research and found a 100MHz Tektronix on Ebay for $300 but I wish now I would have bought the Rigol (new).

Bradman.

I’d be happy to help you out figuring this out. I’ve also repaired a bunch of scopes, although, really only pro scooes like tek and hp are repairable easily (so many parts available, just start swapping boards).

I can also show you what the features are, and how to use our 3 or 4 scooes at the hive, as well as my USB scope. There are advantages to the USB scope as well (I can use mine as a data logger, adc, do math with it, frequency spectrum averaging readings over hours…) however the USB has disadvantages too…

I hate rigol’s analog oscilloscopes. Boo. If you go with a hobby scope these days digital is the best way. Best bang for buck. An old tek or hp from a good source can be just as good or better than those too. Also hit Craigslist. Don’t see em much here, but Dayton, Louisville, and Lexington craigslist have em. I saw a guy selling an in box, functioning 100mhz tektronix digital scope for a couple hundred in Lexington once… Oh, shame I was out of town. There were like 4 in Louisville last time I checked…

Anyway, I think the answer is, start your heterodyning oscillators and RF mixer at the hive and learn our scopes . You’ll know what to get at that point.

Lorin

Bradman: What sort of work would necessitate having 4 channels over 2? Bandwidth I think should be fine even at 20MHz, I’m not going super hight into RF, just 4 MHz. Heck, this first circuit isn’t even heterodyning! It’s just using an Arduino as a counter, assuming any signal is actually coming out.

Lorin: Will you be down at the hive in the next few days? Or even next Tuesday?

Joseph,

Sorry, didn’t mean to be snarky but your needs will determine what equipment you should get.

If you can do with a 20MHz bandwidth then you should be able to save some money.

The 4 channel system is for circuits where you need to watch more than two channels at once. Useful for some needs but not for everyone.

You may even be able to get by with a logic analyzer. I have the Saleae logic that I got for ~$125. They have a new model that even does analog signals. It is rated for 6-25MHz depending on the model. (you should have a bandwidth at least 4 times your desired waveform)

Looking at the analog waveform can be very useful but you will pay for it.

I would play with the scopes that we have a the Hive to see what meets your need.

When you say “the RF range” people tend to think you need mega capability. (150MHz or above).

Here is a link to a good paper about oscilloscopes:
http://www.ni.com/white-paper/4333/en/

I personally like having both analog and digital equipment but I think the sun is setting on the old analog equipment (the digital stuff is getting wicked fast).

Dig around for free and see what meets your need.

Good times,

Bradman

Oops, hope I didn’t come off offended there! I was just curious. And yes, I’m familiar at least with the need for a greater sampling rate than the highest desired frequency. Darn Nyquist thing. Again, not sure I’ll need 4 channels, but I think at this point I just have to come down and poke the Hive scopes, especially once I start on the audio work. (Actually, should start that sooner than later, but that’s another matter entirely.)

Also, regarding the typical implication of “RF”, that’s really good to know, I’ll definitely (try) to keep that in mind!

Thanks!

If Shadoxx’s broken scope is my old Tektronix 465, then I know it was basically working, except for the automatic retrace. If you were hooking up an external trigger to it then it should work perfectly fine; I remember I was able to make it trigger by applying voltage to the manual trigger.

http://w140.com/tekwiki/wiki/465

It did have the optional DMM on top too, but I never tested it.