Is this a good 5-MHz oscilloscope? I Found it in my recently deceased cousins workshop. Seems to work well. Last calibrated in 1987. I would really love to keep it.
Well that sounds like a nice scope. This Tektronix 305 is ancient by comparison but since I don't have anything now it would be a real blessing for me if I can keep it.
Well, Parallax has two USB scopes, I have the cheaper one. And the other one still probably can't compare with your REAL scope. You have more of everything with that "ancient" Tek: bandwidth, voltage limits, trigger options...
If you have a better 'scope put it on ebay and if you don't then keep it as it's better than nothing.
Bear in mind that in real life it's not much use on signals over about 1MHz.
If you're viewing a squarewave the shortest rise/fall time (to 5% of the hi/low voltage) you'll be able to observe is 100ns so a 5MHz squarewave will look like a sawtooth rather than a squarewave.