[TowerTalk] tower ground question

[Jim Lux]

N2EA wrote
>
><snip>
>
>Remember, a 90 degree bend in a ground wire is an inductor, and you  
>want a low impedance
>path for strike current.   I would run that 1.5" strap from each  
>tower leg, with an 18" radius bend,
>over the foundation, and out to each ground rod.


Is there a (probably empirically derived) approximation for the inductance of a bend in a wire.  For straight wires, a handy approximation is 1 uH/meter.  For a curve, are we basically talking about using a standard single turn coil formula, with 1/4 turn?

Some online sites give quick and dirty equations along the lines of L=mu0 * pi * radius.. in any case, an inductance around 1 uH for 1m circumference (radius = 1/2pi meters.. call it about 6").

This would imply that the 90 degree bend is around 0.25 uH.  At 1 MHz, that's an impedance of around an ohm or two.



Jim, W6RMK