[Elecraft] Oscilloscopes

[Ron D'Eau Claire]

Don covered it nicely. Unless you know you'll never use the scope for
anything but routine linearity checking and other simple measurements in the
HF range, get as much bandwidth as the budget allows in both the
oscilloscope itself and the probes. 

The point is that if you put a 50 MHz square wave into a 50 MHz scope, it'll
look a lot more like a sine wave than a square wave because the 'scope
simply won't be able to see the fast rise and fall of the square wave and
will display it with the leading and trailing edges rounded off. For
accurate rendition of a waveform - especially a 'square wave' - I want a
scope with a bandwidth of 10 times the waveform frequency. 

Lower bandwidth scopes will also fail to disclose VHF oscillations that
easily occur in circuits, even HF circuits or voltage regulator circuits
with inadequate bypassing. The 'scope simply won't see such a signal well
above its bandwidth limit or, at best, minimize it by showing it at a much
lower amplitude that it really has. So a low bandwidth scope may show you a
nice, clean signal instead of what is really there. 

I agree with Don, I like analog scopes. Any time a signal is taken to bits
(literally!) and then reassembled there are display artifacts and some
accuracy of the waveform is lost but, you're quite right, analog scopes are
*big* and heavy.

Again, good digital scopes are the more expensive scopes. 

Ron AC7AC



-----Original Message-----

Hi

I'm thinking about buying a scope. I've seen many people recommend 
getting an old analog scope, but they're big! I borrowed a compact 100 
MHz digital scope from work, and it was nice. 50 MHz scopes are a lot 
cheaper, though.

Will I regret getting a 50 MHz scope instead of a 100 MHz one?

73
Jon LA4RT