Hi Gary... As along time user and admirer of oscilloscopes I currently have
three 'scopes: A Hitachi portable with a 20MHz BW and many built in
functions such as a data logger and DMM-it is about the size of one of the
early laptops-meaning fairly large-but functionally was way ahead of its
time, and-with its 4 inch diag. bright blue screen- works very well; I also
have a Fluke 97 handheld with all of the above, numerous math signal
definition and integration functions, a limited signal generator. It is
quite capable-at 50 MHz-of doing almost anything I could need for either a
bench or portable application-I was very fortunate in that I found a new
one a fellow had purchased, intending to set up a 'shop, and the plans fell
through. He sold it to me at a pretty good price (~ 5/8 the going market
value)-WITH warranty card!
Then there is my latest: a Tektronix 7623B I found surplus but new-sealed
in the MIL wrapping. This is a bench type scope with three slots. I bought
it for three reasons: 1) while either of the other two would do fine in use
on almost any bench-well, at 20MHz the Hitachi is a little limited-it turns
out I like the solidity, and sort of presence a bench scope brings. Almost
an anti-portability thing. ( I do not really understand this-its just a
feeling you get using the instruments.) 2) it is a storage scope with
delayed sweep-which really lets you view brief or occasional transient
events and their leading edges; and 3) I was able to get a transistor curve
tracer plug in with the unit, allowing much better than go-no-go/Hfe
measurements on transistors. It also has on-screen readout of settings
which is a feature the newer portables have, but most bench scopes lack-and
is really nice to have.
Which 'scope for you? If you can only get one: definitely a portable-if
it's within your budget. You can just do so many more things with a
portable that leaves a bench scope sitting there. Most of the newer
portables are-at a minimum-50 MHz, so BW won't be a problem. To tell the
truth, most of the math and such features on the Fluke will never be really
used. It IS really nice to be able to read mV, dbM, or db and have the
thing calculate changes and/or differences though. But I got THAT one
because of the opportunity-not the specific features. It was THE best one
at the time, but there are others now offering even more things I might or
might not ever use.
So use that for your evaluation criteria: what are you going to use it for,
and how much can you possibly spend. (After all, it is hopefully a one-time
purchase for many years.)
Dual channel is important; the DMM functions... nice to have but DMMs are
$25-if it comes down to it... reliability is extremely important in my
book... and although I actually worked for Tektronix-and love 'em-I lean
toward Fluke in the portable area.
Finally, if portability is NOT a criteria, the surplus market is flooded
with VERY inexpensive, VERY GOOD, scopes. Stay away from used storage
scopes (the CRTs cost a fortune); stay away from some of the higher BW
7700-series Tek scopes with their 500MHz mainframes... they are a bitch to
calibrate (correctly), and you just don't need the BW.
If you're going to Dayton, I am certain there will be plenty of bench-type
mainframes at great prices. Again, should you be able to afford it, the
portables probably will do the most for you, and-again-I suggest Fluke. I
hope this helps. Good luck.
72/73
Ed Tanton N4XY EMAIL: n4xy@avana.net TEL: (770)579-3933 V/MBX/FAX
189 Pioneer Trail
Marietta, GA 30068-3466
QRP-ARCI#7663 G-QRP#6779 OK-QRP#172 QRP-L#758 AdvRC#140
NORCAL#1779 NCDXF SEDXC
Life Member: ARRL AMSAT IDRA INDEXA QCWA
URL: Coming Sooner or Later
"Think you can, think you can't: either way you're right!" Henry Ford
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