NA: Oscilloscope choices

DaleB

DaleB

Final Approach
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DaleB
I'm in the market for a new(er/ish) scope.

I used a Tek 475A/DM44 in the Army many years ago. For the past 20 or so I've been using a Hitachi V-212, which was kind of a cheap POS when I bought it and has not gotten any better with age. To its credit, though, it has put up with an amazing amount of abuse and neglect and still works... mostly. Anyway, it's time to replace it.

I don't want to go nuts. I use the scope mostly for fairly low frequency work -- audio up to 20 MHz or so. Occasionally I'll need to scope radio signals, but generally it's in the HF range. The most demanding use I put it to is looking at digital signals in great detail looking for ringing, overshoot, rise & fall times, etc.

Given the choice between a Tek 2445B and a TDS320, which would you choose and why? I also looked at the new Rigols, but they're a little more money than I'm looking to spend - especially for a 50 MHz scope. I can pick up one of the above-mentioned Tektronix scopes for $400-450 or less, delivered, with at least a 14 day guarantee so i know I won't get one DOA.

Things that are important to me are a clear, sharp display; ability to display frequency, times, voltages on screen (measured rather than guesstimated from the graticule); and ease of operation - knobs rather than menus, things like that.

What do you like, and why?
 
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Haha... thanks for the page, Tony, but all my scopes are ancient.

It also depends a lot on what you're doing with it... capture depth, how many channels, for how long, looking at digital or analog stuff...

My best workbench "toy" is a old beater IFR 1500 RF Service Monitor. The scope on it is damn near useless for modern digital stuff, but works fine for figuring out "Where the hell did my audio go?" in an analog FM 2-way radio. :-)
 
p.s. Those prices are amazing... I remember looking at HP (before they were Agilent) digital scopes long ago and wondering who had $5K for that stuff... hahaha...
 
Oh yeah. Scopes can be had cheap on Fleabay. The 2445 is light years ahead of anything I've ever used, and they can be had for under $300. It's amazing. I really only need 2 channels, and the ability to capture and store or review a signal is nice - but not a deal breaker.Heck, I've lived without it this long. I find the TDS appealing mostly because I could hook a monitor to it... in theory. Most of the ones for sale seem to have the VGA output option. I don't know if I'd ever actually get around to building or buying a cable to use it, though. Of course they couldn't be bothered to use an actual D-sub 15 VGA connector.
 
denverpilot said:
Haha... thanks for the page, Tony, but all my scopes are ancient.

It also depends a lot on what you're doing with it... capture depth, how many channels, for how long, looking at digital or analog stuff...

My best workbench "toy" is a old beater IFR 1500 RF Service Monitor. The scope on it is damn near useless for modern digital stuff, but works fine for figuring out "Where the hell did my audio go?" in an analog FM 2-way radio. :-)
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Tony?! That's kind of like my mAH blooper. :rofl::rofl::rofl:
 
TangoWhiskey said:
Tony?! That's kind of like my mAH blooper. :rofl::rofl::rofl:
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Bah! Crap. Sorry Troy. Tony probably likes o-scopes too. Haha.

My project this week is to deploy WSUS ... yep, you heard me right... The Linux guy is deploying WSUS.

Describing how that came to be, is beyond even my capacity for words.

My co-workers however have provided me with this handy instructional guide...

u2uragy9.jpg
 
I bought a Tek 2235A just before I got married 27 years ago. The scope is still my go-to scope despite the fact that I've bought bigger and faster ones over the years. OTOH, I've had no desire to try out bigger and faster wives.
 
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Nate:

So patch as in duck tape or patch as in Patch Cables?

"Hey Bill the Audio thing-a-majig isn't working"
"Well just patch around it.... we don't need it. I'll fix it in a few decades...."

If that's the case the tv station my dad use to work for ran off of several LAYERS of patch cables. They had 60s audio chirstmas trees run via patch cables to a digital box via some middleman server. I would follow cables that ran for 20 feet or more to a old unused rack.
 
Lights and switches, baby, hex to binary on the fly.

Toggle "Run" and pray the run light stays lit.
 
One of my crowning geek achievements was one Saturday when we were installing a custom box at a meat processing plant. This was a NEMA-whatever waterproof stainless box that housed a "keyboard wedge", a device that took ASCII input from a bar code scanner and stuffed it into the keyboard port of a 5250-type twinax terminal attached to an old IBM AS/400. There were also a few sealed pushbutton switches that would generate a key stroke.

Anyway, the wedge didn't work the way it should have. Their software required one thing for the pushbuttons, and the wedge was sending something else. The vendor was closed, of course. The device used in the wedge was an 8751; no sweat - I could disassemble the code, find the character map and alter it. I had no 8751s available, but I did have a UV eraser and a programmer. The problem: They used the OTP version of the 8751. One-time programmable, no window to use the UV eraser. And this thing had to work... TODAY.

I figured out how to fix it by only flipping 1 bits to 0 bits, which I could do without erasing the chip. Problem solved, customer happy... just not as totally impressed as they should have been. :) The vendor was pretty impressed, though.

Since we're talking about hex code and assemblers.
 
I bought 3 scopes at an auction recently. I've been meaning to clean them up and post on eBay. Some family stuff has come up, so I can't post anything for a few days. If you can hold out, I can try to post PN's tonight or tomorrow. 2 seem to work, one has an issue....
 
I'll probably be ordering something this week. I've actually been looking at the Rigol DS 1102E this morning, I just heard about them from someone who owns one and is happy with it. 100 MHz digital scope with all the bells & whistles I want for $400, including shipping, brand new from an authorized distributor. It's going to be tough to beat a deal like that.
 
DaleB said:
I'll probably be ordering something this week. I've actually been looking at the Rigol DS 1102E this morning, I just heard about them from someone who owns one and is happy with it. 100 MHz digital scope with all the bells & whistles I want for $400, including shipping, brand new from an authorized distributor. It's going to be tough to beat a deal like that.
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If you do get it, give us a review after you have had it for a few weeks.

Brian
 
I have probably a dozen of the Tektronix TDS scopes at work. Even the lowest-end models are very good. Not sure if they're physically rugged if used in the field, though.

If I were buying one from my own pocket I would look for a used scope. Aside from ebay, there is a more reliable choice -- vendors of used surplus test equipment. Tucker and TekNet are two such companies, and I'm a repeat customer of both. If their website doesn't list what you want, phone them anyway because they might be able to get it for you from one of their usual sources of surplus equipment.
 
How about a Fluke 98? It may be a bit long in the tooth but it's still a good, and relatively inexpensive, scope.
 
Well, after looking at the Rigol I decided to poke around a little more. I just ordered an Owon SDS 7102. 100 MHz, 1Gs/sec, and a whole lot of capture memory. Plus it's got USB host, USB slave, VGA output and a LAN port. I found a guy who posted reviews of that one, the Rigol and a Hantek on Youtube. He ultimately didn't keep any of them, but he was very thorough and covered what I wanted to know. He's a firmware guy, and picky as hell (as I tend to be as well, sometimes). When it gets here I'll post a review after having a chance to use it for a while.

I was seriously considering several scopes. The Owon won out over the rest for a variety of reasons. Ultimately, I feel that unless there's a show-stopping flaw, the incredible utility of having a scope that will do FFT on a signal, save off data to a USB drive or the PC in a usable format, and even put it on my 21" monitor (which has DVI and VGA ports, and I'm only using DVI now) will probably outweigh any minor issues. I fully expect it to be better than the old 20 MHz Hitachi no matter what.

Paid $429 for it, including shipping, a free case and even found a coupon code for a $5 Dunkin' Donuts card. That's brand new from a US distributor (Saelig) with a 3 year warranty and US tech support. Tough to beat that.
 
Man that's amazing. Less than $500 for all that.

I'm sure we all remember when those features weren't available at any price, and something that came close was five digits after the $.
 
I think the Owon does random time sampling so the sample is a function of the time base and trigger and not equivalent time sampling which is synchronous to the sampled waveform. Nothing wrong with that for what you're looking for I think.

The sample rate is 10X the BW which is pretty good. I would have spent up for the 2GHz sample rate as the RT is 1.2nS, but it will likely be ok.

I prolly would have grabbed up a used Tek 475 and sent it though a cal shop, but having a new one is nice too. The 475 had the good CRTs before Tek farmed their displays offshore and they got pretty bad after that.
 
You know, I used a 475 with DM44 back in the early 80s. It was the one Tek put an IBM part number on and sold to the government for something like $8K or $12K (we were servicing IBM S/360 mainframes with them). It was a nice scope... it just won't do a tenth what I want it to do. 99% of what I do is work that probably really only really needs a 10 or 20 MHz scope, so the 100 MHz bw was over-spec anyway. What I am after is the measurements, connectivity, and ability to capture, save and manipulate signal data.
 
mirage00 said:
Here ya go.

http://adafruit.com/products/681
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That's the Rigol I considered and decided against. Actually I was looking at the DS1102E, one step up. I could find them for about $399.

For slightly more than that I got 100 MHz bandwidth, VGA output, much larger & higher resolution screen (8" 800x600 vs. 5.7: 320x240), 10 times the memory and an Ethernet port. Should be more than enough for what I need to do... like I said, I'll post a review once I've had a chance to play with it.
 
DaleB said:
What I am after is the measurements, connectivity, and ability to capture, save and manipulate signal data.
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K, sounds like you got the right one. I prolly would have gone that way too.
 
The new scope came Tuesday. It's a keeper.

It's a LOT different from an old analog CRT scope. Some things, like just twisting the knob for vertical and horizontal settings as you'd expect, are pleasingly easy. Others, like wading through menus, you run into a little deee-luxe Chinese firmware engineering (it's not as bad as the manual). Once in a while it takes me some time to wade through sub-menus to figure out how to turn something on or off, but it does things I never even imagined it will do. It's getting better with practice, though.

In about ten minutes' screwing around, I was able to determine that the audio tone from the new repeater controller I'm working on is dead on frequency at 500, 1K and 2K Hz. At other values you see some integer binary math errors -- 800 Hz is still within 1/2%. And my nifty PWM audio works well; first harmonic is down 30+ dB and the second is about nil. And... I can take screen shots to prove it. :)

I haven't played with all the features yet, maybe never will. I also have not looked to see what Linux software is available for it. It came with a CD with Windows software that I haven't tried, other than to find that it bombs under Wine. But, overall -- $429 well spent. And I gave my wife the freebie Dunkin Donuts card I got with it from the distributor, so she can take donuts to work.
 

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DaleB said:
In about ten minutes' screwing around, I was able to determine that the audio tone from the new repeater controller I'm working on is dead on frequency at 500, 1K and 2K Hz.
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You didn't buy an S-Com 7330!?!

We can't be friends anymore. ;)

Hahaha. Kidding. I know those guys and love their work.
 
denverpilot said:
You didn't buy an S-Com 7330!?!
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Why would I do that? I don't even own a repeater! :)

I'm building the successor to the ID-O-Matic II. It's morphed into more or less a repeater controller over the years, I figure I may as well finish the job.
 
Looks good. I'll have to get used to the digital world some day. Still stuck in analog for visuals.
 
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