[sdiy] Oscilloscope question

[Justin Owen]

Hey all, I have scope question that's now bugging me enough that I'd like to get an answer to it.

I have a 20Mhz Gould dual trace scope which, as cranky as it sometimes is, has served me well this far.

On the 'Time/CM' setting (which sets both traces) I can get down to about 0.5 seconds before the trace starts flashing or pulsing (sorry - not sure what the technical term for this is) - it's like the 'refresh' time/speed is getting slower. At 5 seconds I have a dot going across the screen as opposed to being able to see a complete waveform or line/measurement.

Problem is, when measuring low frequencies (let's say 20Hz to LFO range) to view an entire cycle I need the Time/CM setting above 0.5 seconds - which makes it almost impossible to check the quality or shape or whatever of a waveform.

Right now I'm working on a kick drum oscillator - and for those big long 808 style Booooooms - that's a long old waveform - but it's almost impossible for me to see it in its entirety.

So - if I wanted to look at a scope that could display an entire cycle or at least more info about lower frequency waveforms/signals but with the refresh rate of higher frequencies - what sort of specs should I be looking at?

Maybe I should mention at this point that I only paid a tenner for my current scope. :)

Thanks much.

Justin