Jim, AB4CZ gave you an excellent summary. If you think you'd like to use the 'scope for general bench work to look at waveforms, etc., on HF gear, then look for one with at least a 200 MHz bandwidth.
Smaller bandwidth scopes are fine for a simple check on your transmitter waveform, but one of the greatest advantages to a scope is being able to see things you can't see otherwise - parasitics, the transition waveforms when keying, edges of clock signals, etc. While the fundamental frequency of the waveform may only be a few MHz, the frequency of the squiggles and other artifacts on the signal is much, much higher. For those applications a general 'rule of thumb' is to use a 'scope with at least 10 times the highest frequency you'll be interested in, the higher the better. If you try to observe signals on a narrower bandwidth oscilloscope, the higher-frequency information is simply lost. The displayed waveform will look much cleaner that it really is! For example, if you try to observe a 50 MHz square wave on a 50 MHz oscilloscope it'll show you a nice, clean sine wave, not a square wave. All of the higher-frequency information that makes the edges of the square wave sharp will be lost. To get a decent representation of the actual waveform you'd need at least a 500 MHz oscilloscope. At today's Hamfest prices, the price difference between a basic waveform monitor and a good general purpose scope is often small, and with the latter you have an instrument that will prove itself quite valuable over time if you enjoy tinkering with circuits on the bench. Ron AC7AC _______________________________________________ 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
