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RG6 cable and signal interference?

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Kay Rinne
RG6 cable and signal interference?
on Nov 29, 2016 at 7:52:52 pm

We recently had a client site upgrade cable runs indoors from RG59 to quad-shielded RG6. We are broadcasting live using Sony cameras, HD-SDI out to MC.

Runs are less than 200 feet.
Once the cable were replaced, we can't broadcast in 1080i.
At 720, I get one camera, at 480 I get 2.
(should have 4)

Any thoughts on what might be causing impedance?


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James Hauge
Re: RG6 cable and signal interference?
on Nov 30, 2016 at 9:06:38 am

My first thought was that one of the ends of the video cable might not be crimped/soldered properly...

Then I started thinking about the shielding in those cables and I think that the cable shielding in rg6 might not be the proper kind for what you're using... Please see this article to see if it shed's some light for you...
http://www.milestek.com/blog/index.php/2009/09/rg59-coax-vs-rg6-coax/

That's all I got, I think that it's the shielding in the cable that's causing the problem, and if that's the problem, you might be looking at either replacing the cables again or adding some kind of enclosure around the cables that's shielded...

Good luck!
--James


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Bob Zelin
Re: RG6 cable and signal interference?
on Dec 1, 2016 at 1:10:10 pm

Hi Kay -
I looked at some of your other posts, like looking for someone to do some AE work for you for free to build their portfolio. With that in mind, I can readily tell what is going on here. The very fact that you are using terms like RG59 and RG6 means that you, or your "contractor" went to Home Depot to buy the cheapest crap they could find for your professional production operation. If you kept RG-59, and used Belden 1505A cable, with connectors like 75 ohm Kings connectors, everything would be working fine. If you wanted RG6 cable (which there is no reason to do with only a 200' run), you use Belden 1694A with the correct connectors (and crimped with the correct tools). As has been suggested in another post, you don't get this stuff at Home Depot - you go to Markertek or another professional supply house, and spend $400 for a roll of cable and have it done, and you will have no prolbmes.

When you say "at 720, I get one camera, at 480, I get 2" - exactly what does that mean. I assume you are going into a video switcher. Do you mean that when you plug in a 720p camera, it works, and when you plug in the second 720p camera, the other camera disappears ? Exactly what switcher are you plugging into ?

look - a premade 200' Belden 1505A cable with Canare connectors - all premade for you - for only $119 each and free shipping ! Problem solved -
http://www.markertek.com/product/mbcp-1505a-200/mbcp-1505a-200-canare-slim-...

Who knows what switcher you are plugging into.

Bob Zelin

Bob Zelin
Rescue 1, Inc.
bobzelin@icloud.com


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Kay Rinne
Re: RG6 cable and signal interference?
on Dec 2, 2016 at 2:55:28 pm

Wow, that is some grade A pass-agg elitism Bob, especially since the post you reference is
5 years old.

You're that guy who assumes that once small, always small and that I couldn't possibly be dealing with a large government entity who did the plenum cable installation themselves.

It turned out to be a badly terminated end on the patchbay in the wall. The gov't facilities employees didn't use best practices and ran the cable first, then terminated the ends instead of building the cable, testing it, then running it through the conduit.

But its good to know that in you are up there on Mt Olympus Bob, ready to throw daggers at everyone.


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Bob Zelin
Re: RG6 cable and signal interference?
on Dec 3, 2016 at 1:09:26 am

grade A Kay ? No, I look for budget ways to accomplish things.
And since this is a government job, done by government employees, I am sure that the four runs cost A LOT MORE that the $119 each that I pointed out from the Markertek website. That means that the readers of Creative Cow, and myself, had our tax dollars pay probably 10 times that much, and nothing is still working correctly.
Had this government organization hire a professional AV contractor, this would have never happened, and you would have had a working system from day 1.

And I look up to Mount Olympus, which is where the government spending is - all usually done incorrectly and inefficiently. My clients have very little money - I just try to do things correctly on a tight budget. I observe all the Harris Broadcast installations that are done for the government. What a shame. One of those contracts could employ the entire readership of Creative Cow.

Bob Zelin

Bob Zelin
Rescue 1, Inc.
bobzelin@icloud.com


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Scott Smith
Re: RG6 cable and signal interference?
on Jan 25, 2017 at 10:39:35 pm

Bob's cranky attitude aside, he is completely correct about using good quality cable, and not cheap crap. Much of the Quad-Shield RG-6 is made with a copper covered steel center conductor and even aluminum or CCSteel shields. These are not the best materials for a good low loss cable and HD video. They are awful. I even replaced my CATV runs at home with Belden 1694a, and have higher signal strength and much improved service on TV and modem since I did. So that quad shield stuff isn't even very good for the purpose it is made for.

And I am with him on not understanding your description of how this is being used. What type of signal is on it? What is it for? Good details help get good answers.

Also, If you frequented here a lot, you might actually come to admire Bob's amazing zeal for telling it like it is. I do. He doesn't mince words, but he will actually help you out, if you listen.

BTW, Bob, I work at a state government supported university. I buy my 1694a at the best price I can find (thanks, Walter at Ramtronix) and pull it myself. I'm not going to use my limited budget to pay an idiot to screw it up for me, then have to redo it myself afterwards anyway. But maybe I am an exception to the government employee stereotype.



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