Tom, If your main interest is just in observing the fundemental wave, I would say that a 100 mHz 'scope would be quite useful up through 30 MHz and with caution even to 50 HHz - and with some more cautions, useful for looking at signals up to 100 MHz.
Ron's point is well taken where there is interest in observing for waveform distortion (an indication of parasitics), or for knowing that digital signals are nice and square (that is where the 10:1 rule should definitely be applied). When you push the limits of the vertical amplifiers in a 'scope, even waveforms with lots of harmonic content begin to look like sine waves, and as long as you know that, the 'scope can still be quite useful. There is one other factor that must be considered - and that is the falloff in amplitude response as you approach the upper limit of the 'scope rating. The frequency rating of a 'scope is normally that frequency where the amplitude response is 3 dB down from the response at lower frequencies. So don't expect RF Voltage measurements to be accurate at the upper limit. If you regard the upper limit of the 'scope's calibrated voltage response to be about 1/3 of its frequency rating, all should be good - in other words, a 100 MHz 'scope will provide good voltage measurements up to about 33 MHz. And don't forget that 'scope probes also have frequency ratings to them. Get a set of probes that have a frequency rating equal to or above the 'scope rating - the higher the frequency, the more pricy they become. I like Tek 'scopes, - the Tek 465 and 475 can often be found at $150 to $250. But beware, these and older 'scopes are no longer supported by Tektronics and while repairs by independents are possible, parts availability may be another matter. If you are looking for an investment, go with something more recent, but if you are willing to purchase an older one knowing the drawbacks should something go wrong with it, you can find a good one at a low price. Anywhere between $150 and upward can get a working 'scope, but proper 10:1 probes will likely cost another $100 or more for a pair. Make your choices and like with any test equipment, know your equipment and especially know its limitations so it does not cause you to reach incorrect conclusions. What you see is not always what it really is. 73, Don W3FPR > -----Original Message----- > > I'll follow this thread with interest, as I too am considering a scope > purchase. > > I've heard comments such as Ron's before. I'm wondering if > anyone has any > thoughts on what bandwidth would be appropriate for "casual" use and what > someone might expect to pay for a use one? > > Thanks in advance > Tom > wb2qdg > k2 1103 > > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
