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Posted to uk.d-i-y
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F Plugs
In article
,
says...
On 20/03/2019 12:10, Terry Casey wrote:
I am assuming that the characteristics of the coax are controlled by the
spacing of iiii from the foil, and what material dddd is made from.
Correct.
Actually, this is not correct - it is the ratio of the
diameter of the centre conductor and the inside diameter of
the foil screen which determines the impedance, as we have
previously discussed. Different dielectic materials can vary
the velocity of propagation of the cable but this is only
important if you are using a TDR to trace the location of a
fault.
OK so long as the foil screen is not removed. However, after
the problem I descrihed previously, I wouldn't take a chance.
Even if the foil screen is removed on the stripped bit of the cable, the
padding on top of the PVC sheath is still outside the *unstripped* part
of the cable where is still has full screen integrity.
Yes, but the hole in the connector is now determining the
impedance of that section of the cable. Because the foil is
very thin, this won't make much difference if the correct
connector is used but if the wrong connextor is used there
will quite a jump in the impedance over that section.
The padding, as you say, plays no part in this.
--
Terry
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