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Old September 8th 06, 05:36 AM posted to rec.radio.amateur.equipment
BobH BobH is offline
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First recorded activity by RadioBanter: Sep 2006
Posts: 2
Default Advice on Oscilloscopes Sought

jawod wrote:
Being relatively new to ham radio, I am considering some form of
oscilloscope. I am intrigued by PC-based systems (eg., BitScope Pocket
Analyzer)

I've read a few NG posts about used HP scopes and a few negative remarks
about PC scopes.

My question:

Given my neophyte status and the likelihood that I would use a scope for
anything more the basic / with learning, moderate/ complexity,
... is the PC-based scope a good choice for me?
Cost is under $400, not incl. a $40 analog probe.


You don't say what you want to measure with a scope, and it is very
important with a digital storage scope.

Nyquist's theorem says that if you are sampling at 2x the highest
frequency present, you can determine that frequency. My experience with
digital storage scopes is that you want at least 5x the sample rate and
10x is better to look at a waveform. As a result, a 20 MSample/sec scope
is useful up to 2 - 4MHz of input bandwidth. Beware, some of the digital
storage scopes specify a "repetitive sweep" bandwidth that is equal to
the Nyquist rate. If you are looking at a repetitive signal, you
actually can approach this rate. If you are looking at a one-time or
rare event, the usable bandwidth is much lower. Exceeding the bandwidth
of an analog scope gives you a distorted view of the amplitude and
possibly the waveshape. Exceeding the Nyquist rate on a digital scope
becomes outright deceptive in amplitude, waveshape and frequency.

Unless you need a DSO, I would suggest you look for a good used analog
scope. Tektronix made some really nice analog scopes and the 465 is one
of the best. HP's analog scopes were always a disappointment to me, but
their digital scopes are first rate. As a solid scope, for learning and
genearal utility, analog scopes offer a lot more bang for the buck.

Good Luck,
Bob