Tom Rauch wrote:
>>>It sounds like an "old wive's tale", but, it doesn't
>>
> cost anything to
>
>>>tie knots
>>>between the equipment and the outlet...spikes *hate*
>>
> inductance...
>
> That goes right along with the jar full of salt water filled
> with pennies in the radio room and the aluminum pie pans
> over the coax as deflectors that my neighbor has.
>
> I'll have to tell him to tie knots in his power cords!
>
>
>>Well, no again. Tying knots in cables may do something but
>
> may in fact
>
>>do harm. A loop in a cable while providing some series
>
> inductance is
>
>>also a great magnetic loop antenna. It can increase the
>
> pickup of
>
>>induced fields from conductors carrying the strike
>
> current. Be careful
>
>>where you use them.
>
>
> Come on now, let's think about it logically for a moment.
> The "inductance" of a knot is probably in fractional
> microhenries. Not much more than the same wire length in a
> straight line, and insignificant compared to the distributed
> impedance of even one foot of wire in a straight line.
>
> The knot idea really does fit well with the pie pans and
> salt water jar of my neighbor. Unless of course it is a two
> foot diameter knot in a strategic location....
>
> 73 Tom
>
Hi Tom,
I would guess that you have in mind rather tight knots and I picture
rather large loops of wire being used. Loops in transmission lines after
bulkhead protection panels or loops in power lines after this point that
are near by the unprotected side can indeed pick up substantial
currents. You don't even need loops in them to do so. It is recommended
to keep the protected side of lines well away from the unprotected side.
A mistake that is often made at the bulkhead is running the protected
lines parallel to the unprotected side of the lines when coming off the
panel.
73
Gary K4FMX
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