I haven't touched RF test and measurement equipment for about 20 years.
Back then I used a standard 50MHz dual trace scope. I want to get
back into homebrewing, and was wondering whether anyone could advise me
on buying PC based 'scopes. Do they have the same "look and feel" as a
dedicated 'scope?

There appear to be many such PC based scopes (e.g. Vellman), I was
wondering what homebrewers would advise, given the "average" budget
(not 10,000 Dollars + !!). Something with a pretty good Spectrum
Analyser built in?

Or would I be better off going to Ebay and buying an old dual trace
scope for 100 Euros or so?

Advice anyone?

wrote:
I haven't touched RF test and measurement equipment for about 20 years.
Back then I used a standard 50MHz dual trace scope. I want to get
back into homebrewing, and was wondering whether anyone could advise me
on buying PC based 'scopes. Do they have the same "look and feel" as a
dedicated 'scope?

There appear to be many such PC based scopes (e.g. Vellman), I was
wondering what homebrewers would advise, given the "average" budget
(not 10,000 Dollars + !!). Something with a pretty good Spectrum
Analyser built in?

Or would I be better off going to Ebay and buying an old dual trace
scope for 100 Euros or so?

Advice anyone?

Andy writes:

I've used a couple of the systems that plug into the PC and use
software
loaded into it. It is mainly an A/D converter with several channels,
and
the software gives the user the versatility to establish timing, etc...
I MUCH MUCH MUCH prefer the old fashioned analog scopes, tho, since
I can fiddle with it and don't have to worry about aliasing, sample
rates, etc.
I suppose the latter software programs have all the user friendly stuff
built in, but, personaly, if I didn't write the program myself, I don't
know
where I would get into trouble applying it. I don't like to used
"canned"
"one program does all" stuff....... (unless I wrote it :))) ).

One really cheap system I used was, I think , BSOFT. I don't know
if
they are stillin business, but they sold a board that plugged into a PC
(desk size) and only cost 50 - 100 bucks. Worked up to several Mhz.
But that was 15 years ago -- everything is much faster now -- but you
have to pay for it......

As I think about it, a big advantage for a PC scope is that the
measurements
are on a file somewhere, and if you have programming ability, you can
write an FFT, or a graph program, or, well, hell, almost anything
you
can think of ---- providing you can access the data file.... That
could be
a lot of fun.........

Good luck. But 50 mhz scopes are faily cheap now......

Andy in Eureka, Texas

wrote:

I haven't touched RF test and measurement equipment for about 20 years.
Back then I used a standard 50MHz dual trace scope. I want to get
back into homebrewing, and was wondering whether anyone could advise me
on buying PC based 'scopes. Do they have the same "look and feel" as a
dedicated 'scope?

There appear to be many such PC based scopes (e.g. Vellman), I was
wondering what homebrewers would advise, given the "average" budget
(not 10,000 Dollars + !!). Something with a pretty good Spectrum
Analyser built in?

Or would I be better off going to Ebay and buying an old dual trace
scope for 100 Euros or so?

Advice anyone?

You might want to check how much RF your PC is leaking first.

Also check to see if the software can be run directly off a CD
without installing anything on your HD. My PC has enough
to do already. I prefer a dedicated time-based oscilloscope.
RF spectrum analyzers are expensive cupholders, nice to have
but ... well, if someone gave one to me for free I wouldn't complain.

"AndyS" wrote in message
oups.com...
I MUCH MUCH MUCH prefer the old fashioned analog scopes, tho, since
I can fiddle with it and don't have to worry about aliasing, sample
rates, etc.

A *good* digitial scope will contain an anti-alias filter and sufficient
smarts that you genereally shouldn't have to worry about these issues -- if
you were to take a new Tektronix or Agilent DSO (or at least the "mid-grade"
or higher "trim levels" -- the ones that show properly shaded waveforms to
indicate how much time signals spend at various levels), I'm willing to bet
you'd be just as happy as with your old analog scope.

Not that there's anything wrong with the old analog scopes. :-)

One of the main problems with inexpensive PC-based oscilloscopes is the fact
that the specs are often considerably "low end" but often not presented in a
way that makes this apparent. I honestly believe that some people think
that hooking an analog signal directly to the input of, say, a 100Msps ADC
somehow makes a "100MHz scope." :-(

Here's a nice comparison from cleverscope -- people who do seem to know what
they're doing -- that compares various PC-based scopes:
http://www.cleverscope.com/resources...on%20chart.pdf

---Joel Kolstad

ORIGINAL MESSAGE:

On 18 Jul 2006 15:53:23 -0700, "AndyS" wrote:


I MUCH MUCH MUCH prefer the old fashioned analog scopes, tho, since
I can fiddle with it and don't have to worry about aliasing, sample
rates, etc.

------------ REPLY SEPARATOR ------------

Analog scopes are good when the human eye can perceive the trace
adequately. Digital scopes are best with waveforms that are either too
slow or too fast (and non-repetitive).

Each has its place.

Bill, W6WRT
retired test technician, Tektronix 400-series portable digital scopes

Joel Kolstad wrote,

I'm willing to bet
you'd be just as happy as with your old analog scope.


Andy comments:
I admit that I haven't used a digital scope since I retired 5 yrs
ago, but , in my opinion, they have TOO DAMN MANY buttons !!!!

It was frustrating to have to use a new digital scope that I was
unfamiliar with whenever I had to visit a different lab and give a
hand.... Took longer to figure out the scope than to solve the
problem......

"You might can teach an old dog new tricks, but only if
he wants to learn them" :))))

..... from The World According to JungleAndy (W4OAH)


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