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Old January 28th 14, 08:26 PM posted to rec.radio.amateur.antenna,sci.electronics.basics
Jeff Liebermann[_2_] Jeff Liebermann[_2_] is offline
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Default I have question about R L Mathematics

On Tue, 28 Jan 2014 13:03:35 -0600, amdx wrote:

I have beads* on a coax and want to know the R and the L.
I have measured the R at 3.85MHz, It is 3,350 ohms.


Measure it again. That's an awfully high resistance for a piece of
coax cable of any length. Knowing the type of coax and the length
would be handy. Hopefully, you're not measureing the resistance of
teh broken pot cores. That won't work.

* it is actually a bit more than beads. Years ago, we were sent a box of
ferrite potcores, the cores arrived broken. I slide 42 broke halves onto
a piece of RG59, and now I'm measuring it.


The inductance of gapped and non-gapped ferrites are quite different.
Check to see if the inductance moves when you move the coax. Also,
RG-59/u is not the best coax on the planet. Try to find some RG-6/u
instead.

You might want to read through these papers on ferrites (especially
the first):
http://www.audiosystemsgroup.com/K9YC/K9YC.htm

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Jeff Liebermann
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