Shielding question when putting on F connector on RG6Q - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 5 Old 07-01-2014, 09:23 PM - Thread Starter
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Shielding question when putting on F connector on RG6Q

I am very much a rookie in this area. 7 months ago I dropped cable and strictly use netflix/amazon prime and OTA. I just bought a new house and after looking at previous cable runs, which are all ran to walls I don't want a TV on, and using older coaxial cable.. I decided to run my own. I bought a kit for compression F connectors and I did a couple runs already, from antenna to splitter to tv wall to tv.

Anyways, when preparing myself for this, apparently I only watched youtube videos on making RG6 cable. After I already made 3 cables, I found out that everything and everywhere says you are supposed to pull back the 2 layers of wire shield and remove the one layer of foil, leaving just one layer around the white part.

Well, when I made the 3 cables, I only pulled back the first wire shield layer and left the foil-wire-foil shields.

The question, Why are you suppose to pull back first 3 layers on RG6 quad shield?

The connections I made work, and the f connectors are on tight. So really, why is there all of this you NEED to pull back 3 layers leaving the last foil layer intact? Is there some actual technical reason or is it to just provide more mass for the compression connector to snug against?

(sorry if this has been posted before, I searched and searched and only found stuff saying that you are supposed to pull back the 2 wire layers and remove the first foil layer, nothing saying as to WHY you are suppose to do that)
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post #2 of 5 Old 07-02-2014, 04:35 AM
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The foil on most cables is only conductive on one side, with an insulating coating on the other, which helps it maintain a close contact with the adjacent braided-wire shield. That way, the two layers become "broadbanded".....one works better at the lower frequencies, and the other works better at the high end.
By removing the middle foil only at the connectors, you allow the two "sets" of shields to make contact with each other at that point only. The rest of the way, they are separated electrically, so you have two pairs of shields, each working to add isolation from outside noise.

The inner-most foil is critical to maintaining the proper impedance of the cable, and should be kept smooth and intact. That's why it should slide easily in to the inner sleeve of the connector.....the ratio between the outer diameter of the center wire, and the inner diameter of the first (innermost) shield, determines the impedance of the cable at any point along the line. Impedance "Bumps" are what cause reflections at various frequencies, which distort the signal. That's what used to cause visible "ghosting" in an analog picture. It now causes "blurring" of the data in Digital signals.

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post #3 of 5 Old 07-02-2014, 05:01 AM
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I agree with the previous post; however, I don't think you will have an issue. As described, the cable is a transmission line with the impedance controlled due to the spacing between the inner conductor and foil layer. I think you will always have a bit of an impedance mismatch at the connector, regardless of how the connector is crimped. The cable is also not perfect. I've crimped connectors many different ways due to trial and error and never seen an issue...bottom line is you likely have a good electrical connection between the foil and the connector and the resulting impedance at the connector is good enough
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post #4 of 5 Old 07-02-2014, 04:49 PM - Thread Starter
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Good info, thanks for the replies guys!
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post #5 of 5 Old 07-02-2014, 05:18 PM
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There are some cheap RG6 coax strippers that do all 3 cuts at the same time at the proper depth. They work really nice. And the good compression fittings are the only way to go.
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