Does the shield need to make electrical contact with the connector? - AVS Forum
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post #1 of 10 Old 10-25-2013, 06:35 PM - Thread Starter
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On RG-6 cable, does the shielding need to make electrical contact with the connectors on both ends of the cable? Or is the shield effective without making contact with both ends and whatever it's connected to?
I ask because I purchased an antenna, couldn't get reception, and returned it. I thought it was because I couldn't aim it correctly due to my apartment building's configuration. However, I tested the cable, and found continuity on the copper conductor only. The connectors themselves did not have electrical conduct. I used one of those cheap screw on connectors.
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post #2 of 10 Old 10-25-2013, 07:51 PM
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Yes you need to be connected. Use decent fittings and install them properly.
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post #3 of 10 Old 10-25-2013, 08:13 PM - Thread Starter
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Quote:
Originally Posted by olyteddy View Post

Yes you need to be connected. Use decent fittings and install them properly.
Could it have literally made the difference between not receiving anything at all and solid reception? I'm not able to point my antenna at anything and I know it's line of sight for TV. I don't want to go re-buy an antenna unless this could have been a real culprit.
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post #4 of 10 Old 10-26-2013, 08:51 AM
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It likely was receiving such a mish-mash of distorted signals, that the Digital receiver's equalizer could not make anything out of it.

Ken English, Sr. Engineer, KSL-TV.
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post #5 of 10 Old 10-26-2013, 10:02 AM
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Quote:
Could it have literally made the difference between not receiving anything at all and solid reception?

Yes, the shield needs to be connected at both ends, it's required to complete the circuit.
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post #6 of 10 Old 10-26-2013, 10:31 AM - Thread Starter
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Ok, great. Is there any way to test the cable I have using a multimeter - beyond simple continuity? I'm able to come up with resistance readings, but they are dependent on the cable length I believe. IE when set to 200 ohms, it says about 1.7, but other cables have different values.
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post #7 of 10 Old 10-26-2013, 06:05 PM
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Using the ohmmeter feature you should have continuity between the two ends of the shield and between the two ends of the center conductor. You also must test between the center conductor and the shield to check for a short.

Coax that has a center conductor that is solid copper will have a lower DC resistance than coax with a copper coated steel center conductor. Longer cables will give a higher resistance reading, but it shouldn't make much difference to the signal unless it is very weak, because it has a very small current that travels on the outer surface of the center conductor. This is called the "skin effect." Longer cables will attenuate the signals; the attenuation factor for RG6 is about 6 dB for 100 ft. for UHF.
http://www.digitalhome.ca/forum/showpost.php?p=863639&postcount=3

If you are not able to bring both ends of the cable near each other you can test a cable by disconnecting both ends and shorting the shield and the center conductor at one end. This should show continuity thru the center conductor and the shield combined at the other end. Remove the short at the first end to test for a cable short.

If you can not measure it, you can not improve it.
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post #8 of 10 Old 10-29-2013, 05:13 AM - Thread Starter
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Here's another question. Can one connect two or more antennas in series, and point them in different directions to gain more signal, or more channels? Or, do you just end up with that much more noise for the tuner to filter out?
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post #9 of 10 Old 10-29-2013, 10:33 AM
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Multiple antennas can be done but a matching pad should be usedd to tie the two antennas leads together and maintain the proper impedance or the gains will be lost in the mismatch. One trick when mounting outside connectors at antennas is to wrap the connector in electricians tape and then cover with silcon sealant. That will last twenty years and when disconnection is needed, a simple pocket knife will break the sealant and the tape to unpeel it easily. Grounded connectors is essential to a complete circuit.
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post #10 of 10 Old 10-30-2013, 06:58 AM
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You can combine two antennas with a (backwards) splitter, but any time you do that, it's going to be a crap-shoot as to how they interact.
Varying atmospheric conditions and multi-path will cause strange addition/subtraction effects across the individual channels, and may sometimes cause you to lose a channel.

As for "more signal", yes, you can stack antennas (identical, and pointed in the same direction) for more "gain"....which is really just a narrower beam-width.

When a big system uses multiple antennas, they process each channel individually. It's pretty complex and expensive. A "mid-range" priced system might use a Programmable Filter-Amplifier, which allows you to program different inputs (antennas) to different channels. They run around $1K for the unit.

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