ORIGINAL: combatpigg
My main point about using distance/time VS other methods is that it is practically free and very accurate. If I'm shooting for 200 mph, and radar or wave-o-scope data shows speeds in the 195-205 mph range, there is still a shadow of a doubt. I wouldn't feel good about the findings until they were validated with a stop watch...which brings us back to "square one".
There is no doubt this is one of the cheapest way's to go. The accuracy is solely depended on how fast your fingers can move on that stop watch. If you are at the starting point there is a time delay by the time you get a signal the plane has past the ending point. Just a one second delay on the starting point on ending point at 200mph could give +/- 5mph. Witch would make this no more accurate than most radar guns out there. I think to most accurate way is to use a laser radar gun that most of us don't have access to. So until laser radar guns are cheep we will just all have to use the way we feel is the best.