Coax question? - Canadian TV, Computing and Home Theatre Forums

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post #1 of 8 (permalink) Old 2020-02-13, 10:33 AM Thread Starter
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Coax question?

Picked up a new 50 ft roll of GE RG6 quad shield coax to replace a run that had gotten water in it. When I double checked the isolation and conductivity in the roll I was surprised to find the shield portion does not show continuity between the connectors (isolation and conductivity of the center wire is good of course). Is this a defect? Seems like all previous cables that I recall did have continuity through the shield.
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post #2 of 8 (permalink) Old 2020-02-13, 11:14 AM
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Yes you need continuity on the shield, especially if you use a pre-amp which is powered via the coax. Check your connectors. Quad shield, to my recollection, may require special F-connectors (if not already supplied).

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post #3 of 8 (permalink) Old 2020-02-13, 11:44 AM
 
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Quote:
Originally Posted by paxplant View Post
Picked up a new 50 ft roll of GE RG6 quad shield coax to replace a run that had gotten water in it. When I double checked the isolation and conductivity in the roll I was surprised to find the shield portion does not show continuity between the connectors (isolation and conductivity of the center wire is good of course). Is this a defect? Seems like all previous cables that I recall did have continuity through the shield.
How did you test for this, what tools, etc.?
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post #4 of 8 (permalink) Old 2020-02-13, 12:32 PM
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Most voltmeters have a DC resistance measurement function. It should be close to zero for both the conductor and shield for 50' of coax. DC resistance between the conductor and shield should be close to infinity. That's not the same as cable impedance, which comes into play at RF frequencies.
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post #5 of 8 (permalink) Old 2020-02-13, 03:55 PM
 
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You will need connectors that are rated for quad coax because the quad is thicker and presents a challenge to install. Also you must have continuity between the 2 shields and the tin foil wrap.

There should never be any continuity between the center conductor and the shields.

Just as a side, unless you live in an area which is inundated with all kinds of interfering stray RF fields, good quality RG6 is all you need!

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post #6 of 8 (permalink) Old 2020-02-13, 08:11 PM
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Wink

One other situation I can think of where quad shield may be a better choice than dual,
is if you are powering electronics at the other end of a really long run, such as a preamp, or diseqc Ku satellite motor + LNBs. Quad shield would have much lower DC resistance in the shield than the regular stuff. So would cut down on the DC voltage dropped across the coax.

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post #7 of 8 (permalink) Old 2020-02-20, 03:46 PM Thread Starter
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Sorry for the delay in closing this out. I found that the external portion of the connectors (hex nut and crimped area) on this coax are not directly connected to the shielding. The center ring within the connector is! Screwing coax connectors in each end of the quad shield I found continuity between the connector barrels. Works great!
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post #8 of 8 (permalink) Old 2020-02-20, 08:52 PM
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Glad to hear you now have continuity.

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