[TowerTalk] Cable on a reel using a formula?

[David Hachadorian]

Google is amazing:
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Suppose the reel has hub diameter Di, outside diameter Do, and width
W. Then the volume of wire on it is

    V = pi(Do^2 - Di^2)W/4

Suppose you have a wire with length L and square cross-section with
side Dw (the diameter of the wire). Its volume is

    V = LDw^2

Setting these equal, we get

    LDw^2 = pi(Do^2 - Di^2)W/4

and we can solve to find

    L = pi(Do^2 - Di^2)W/(4Dw^2)-------------------------------This 
formula assumes zero airspace in the windings, so it should overstate 
the length somewhat.Dave Hachadorian, K6LLYuma, AZ