Topbanders,
for the construction of the beverage ( a 2 wire reversible beverage,
that is) from my post a few days ago i wanted to know how to measure or
determine the impedance of the open wire. I stumbled across a very
simple method some of of you might know , some might not. Anyway, here
is the method. It works for coaxial cable or open wire.
You need no fancy measurement gear- rule, pocket calculator and LC
meter will do. For really long runs you might need the help of a tape
rule or even google maps.
Measure the length of the unknown coaxial cable or open wire (DUT Device
under test) in meters m.
With both ends open, measure capacitance C of DUT, divide it by it's
length ( C' = C/m) .
Shorten one end, measure inductance of DUT, divide it by length ( L' =
L/m) .
Now calculate
Z= 1000 * squareroot(L'/C')
Voila.
It may also help to determine if and where your cable or 2 wire beverage
has an intermittance when you already know it's impedance it had before
the failure. Transform the formula accordingly.
I think it should also help to determine the impedance of the beverage (
single wire or 2 wire) measured against ground(?).
--
Ohne CW ist es nur CB..
73, Martin DM4iM
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