Need pointers on Oscilloscopes

Chuck Guzis cclist at sydex.com
Thu Jun 8 20:59:54 CDT 2006


On 6/8/2006 at 8:28 PM Wolfe, Julian wrote:

>I'm going to go to a hamfest this weekend to look for an oscilloscope.
>
>Do you guys have any pointers on what to look for, and how to know if what
>I'm looking at has problems?
>
>Any advice would be appreciated.

What do you plan to use the oscilloscope for?  Do you need a lot of
bandwidth (usually means $$$); do you need a storage scope? ($$$)  Are you
in the market for a DSO? ($$$$)  Are you looking for a lab scope with
plug-in modules or just an all-around basic unit?  

A number of folks find that the older Tek all-vacuum-tube scopes can be
quite exceptional  for low-speed analogue use.

If I were looking for an inexpensive used scope for nonspecific
general-purpose use, I might consider one of the more ubiquitous models,
like the Tek 465.   Bandwidth (depending on model) is a useful 100-200MHz,
triggering and delayed sweep are usuually rock-solid; a regular workhorse.
Occasionally, you can find an exceptional deal in a Tek or HP scope that's
been mounted on a rack panel.  (Just drill out the spot-welds and add some
feet).

If possible, find a scope that's been calibrated regularly.  Don't forget
the probes--a cheap  probe can really degrade operation, so make sure that
the probes are intended for use with the unit and not somone's generic
piece of wire.  Make sure that all of the indicators work, the display can
be focused and there are no burn marks on the screen and the controls and
switches aren't noisy.  Most scopes have  a calibration test function, so
you can at least get a ballpark idea of the thing's operation.

Stick with a brand name unit--Tektronix, HP, LeCroy, etc.  There will be a
larger community of users (and hence more replacement parts) for those.

Cheers,
Chuck





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