Did my Shake pick up the sound of an aircraft?

[PhilipPeake]

Ha! I just did a reply to another post showing how to do it. The two f’s are actually not equal … but it is probably good enough to assume they are for these purposes.

Four Apache AH-64 helicopters passing exactly overhead

Not sure that I totally follow his calculation … but he does end up with about the right answer, so it obviously works for him. There are a few problems with trying to estimate speed from these traces, the most important one is that (as in this case) the helicopter has to fly pretty much directly overhead. Assuming that to be the case, the calculation using the only really measurable parameters (approach/depart frequencies) is non trivial. At least if you want an accurate answer. You can’t jus…