buying an oscilloscope

[Tony Duell]

> 
> David,
> 
> I agree with whomever wrote about sticking with Tek analog scopes. If you
> want your squarewaves to look square though you need a bandwidth 10 times
> the signal of interest ( i.e. 20 MHz squarewave 200 MHz scope ). The more

Actually, you can get away with less (3 times is the absolute minimum, 
for obvious reasons) if you know how your 'scope is going to behave on 
that sort (and frequency) of signal. You'll not get the textbook traces, 
but if you know what to expect, you'll know when it's not right...

> odd harmonics you can push through the more " square " it will be, and you
> would like to pass the 3rd, 5th, 7th and 9th harmonics if possible. I still
> like my OLD Tek ( 5000 BTU, Ethan could use this in the South Pole ) 535A
> with CA plug-in for most old vintage stuff. The display is still as crisp

And my 555 is alongside me right now :-)

> and bright as the day I bought it ( used at a salvage sale ). I have a high

About 15 years ago, we got a new Tek CRT 'scope where I was working. I 
tried it out, and to me the trace wasn't sharp. I complained to Tek, who 
claimed it was within spec, and asked what I was comparing it against. I 
said 'My old 555 at home'. Their comment was that the old 500 series had 
wonderfully sharp traces (if correctly set up), and nothing afterwards 
comes close...

> dollar Tek digital LCD scope but was very disappointed to find out the 2 GS
> / second front end is only 8 bits wide !!  I only use it if I need a
> hardcopy for a customer of some signal or to capture a signal that only
> happens once. The signal displayed is only as " crisp " as the dots in the
> LCD are small. Good luck in your search. Now, if you could find an HP
> LogicDart cheap somewhere ......?

Good luck :-). That's a wonderful instrument that was totally 
mis-marketed by HP, so nobody tired to buy them until it was too late :-(

-tony