Mark . wrote:
> Kieth wrote:
>
> << Pi * r squared is area of a circle. What you will need is 2 * pi * r, or
> pi * diameter, which is circumference. However, this is accurate only for
> the turns on one radius. You can get fairly close by counting the outer
> turns across the reel, then estimate how many layers there are to the inner
> layer, then adding all together. Calculate circumference using r measured
> from center of layers to center (axle) of reel, and multiply by total number
> of turns...SNIP...73, Keith NM5G >>
>
> Keith has got it, and this requires an iterative solution: estimate a
> packing factor (for how neatly the coils nest), calculate the number of
> layers, then the number of turns per layer, and then calculate the cable
> length for each layer, adding them up as you go.
>
> I wrote a handy 'hose length calculator' program to solve this problem
> using BASIC in the late 80's. In planning the installation of a CCTV system,
That is one way to do it. But as another poster relayed, finding the
volume of the reel and the volume of the cable is a much easier way to
do it. Then you don't care how many layers or turns are on the reel.
73
Gary K4FMX
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