Anyone use these? Any recommendations good or bad? I am looking at some that
have Scope, Meter, Spectrum Analysis, etc. Are the "multi-use" type PC
scopes any good? I see some that are down around $200-300? which is in my
Carrollton, TX USA 75006
Depending on what you are trying to measure,
they can be a very usefull tool. A "real" scope is
much better, but much more expensive. IF you
can, try before you buy. At the very least get to
do a hands on demo. I use several different
audio applications for a variety of my measurement
needs. For the serious stuff, I borrow a good scope
The biggest "flaw" is they average the readings,
so if what you are looking for is a rarely occuring
gltich, a most PC scoes will miss it. For looking
at normal waveforms they do a respectable job.
My gut reaction when I see a PC-based O-scope is to cringe.
I would stay away from them. For the same price range that you
mention, you could get one heck of a nice Tektronix 7000 series 'scope,
or perhaps a 400 or 2400 series portable, all from the used/surplus
arena (more specifically, from ham radio swap meets or Greed-Bay).
Example: The Tek 7603 was one of their most popular, and is also
one of the most plentiful on the surplus market. It has a mainframe
bandwidth of at least 100MHz, and can often be found for around $50-$100
If you want some serious bandwidth, you should have a look at the
Tek 7904 or 7104. The base frames have bandwidths of 500MHz and 1GHz,
respectively, and you should be able to get a good 7904 with plug-ins
for a little over $300.
Your test equipment needs are, of course, your choice. However, I
would like to say that just because a test instrument CAN be designed to
work in a PC environment does NOT always mean that it SHOULD be. Good-
quality input stages are hard to do (there's a reason Tek put so much
R&D into theirs), and they are one of the main driving factors where
cost is concerned.
I have little faith that the Taiwan-import PC-based (alleged) O-
scopes can do a proper job in this regard. Good quality test gear is an
investment, and it should be treated that way.
Keep the peace(es).
There's one major advantage to the PC based scopes. It's STORAGE of
waveform. When I was younger we had to put a hood over the front of the
scope and use a Polaroid to get shots of easy to miss signals.
A real storage oscilloscope costs a fortune, but if you can get a PC variety
that fills your frequency needs, I'd go for it. Three or four hundred bucks
is a bargain when accompanied by a good warranty..
Some of them aren't too bad, although in the $200-300 range you'll not
get any record setters. For one data point, though, some of the higher
end scopes do use Windows as their user interface. Check out Tek's
For one possiblity closer to your price range, take a look at
I have not used their
o-scopes but I have (and use) one of their PC-based logic analyzers.
Been reasonably happy with it.
I love damnation by faint praise. It's a good thing you haven't heard me
trying to practice this bass. You'd retract that
EADG EADG I mean. sheesh..how hard can it be? I'm starting to suspect
they shipped the wrong instructions with it, not that it matters, I can't
speak Chinese anyway.
Tektronix DSA602A Digital Signal Analyzer. All kinds of waveform
storage and analysis, and a floppy drive as well. Runs about $400-$500
on the used market, uses 11-series plug-ins, mainframe bandwidth of
And how long will it last? If it's made up entirely of custom
parts, and cannot be repaired by the end user (at least at the module
level), then I would hardly think of it as a good investment.
When I buy test equipment, I expect it to be serviceable for a
MINIMUM of ten years. Very few items that I've bought new have measured
up to that requirement.
You make some valid points, but I still have concerns. Tektronix, among many
others, has been known to use proprietary chips/components in their scopes.
These may be getting hard to get. That would tend to even out the decision
making process, all other things being equal.
Having said that, Tektronix stuff is very nice, quality made merchandise.
I'm admiring a 7B92A dual time base module even as we speak. I just don't
want to wind up like Hamlet...
Alas, poor 7904, I knew it Horatio...
My personal preference is a conventional benchtop
scope for high frequencies, and a sound-card-based
PC scope for audio work. I use my own Daqarta
shareware for the PC scope (shameless plug). It
only runs in real-mode DOS on old ISA-bus systems
with Sound Blaster cards (or lab-type boards, which
are pricey). I run an old cast-off 16 MHz 386 system
that works just fine for this purpose.
The PC gives me real-time spectral analysis, which
is great for distortion measurement and especially
for distortion adjustments. Another big advantage is
that the PC can generate complex test signals and
keep them exactly in sync with the input signal
that is responding to those signals, so you can
use signal averaging to measure noise *way*
below the noise floor.
Windows-based version is under construction,
but won't be released for several months yet.
Hope this helps!
D A Q A R T A
Data AcQuisition And Real-Time Analysis
There are several places around the internet that sell reconditioned
test equipment. You might end up spending a bit more than at ebay but
you (should be) getting something that has been cleaned, op tested, and
has all of its parts. Possibly also a better warranty.
There are a jillion out there, but a couple that I get periodic catalogs
< Top-posting corrected. Please don't top-post! See this link for
the reason why:
for hamfests in your
area. They happen all over the country (heck, all over the world) at
various times during the year, and the swap meet portion of any hamfest
bears (usually) a 95% or higher focus on electronics in terms of test
gear, radios, computers, etc.
If you've never been to such an event in your life, I would
(SHAMELESS PLUG ALERT) take a look at an article I wrote on my own page
at this link:
This is a guide to scrounging at both surplus places and swap
meets. I hope you find it helpful.
It is very rare for a cross posted article to RRS to be useful. Most are
Trolls. I enjoyed your web page on scrounging. I'm taken aback on the
prices that you posted about equipment however quoted below.
A TDS7104 sold new in the $30K to $40K range depending on options. I
have priced this scope at used equipment resellers in the $8 to $10K
range. The equipment is sold in calibration and working with a short
warranty like 30 days for verification that the equipment is in proper
working condition from resellers.
At prices under $1K even with no guarantees I expect this equipment is
hot at those prices. All equipment from the major makers have serial
numbers throughout the equipment and in the firmware. If you ever send
this equipment in for repair you might be in for an unpleasant surprise.
In the last few years there is a new class of scope called real time.
The reason I'm responding to this thread is that you just happened to
mention a real time scope the TDS7104. Tek calls real time scopes DPO or
Digital Phosphor scopes. Most digital scope are repetitive sampling
making them a poor choice for low frequency events like an intermittent
pulse and these are useless for high speed single shot events. The DPO's
resemble an analog scope with memory. There are the best suited digital
type for single shot or low frequently occurring events. The DPO's are
designed for a very high re-acquisition rate compared to digital
sampling types, which is why they are better suited for the low
frequency events as they are more likely to be actually sampling the
input during an event rather than being in another part of the
processing cycle. DPO's have a rapid processing cycle and also have most
of that cycle being actual sample time so they are able to catch that
infrequent pulse. The repetitive sample high speed scopes generally have
cycle times of 200KHz or slower and most of that cycle time is signal
processing and display. Repetitive sampling scopes are good at any type
of recurring signal like clocks. They are poor choice at looking at data
streams with long patterns. The only way you can look at long patterns
is at the bit level or eye mode.