I have some resi. contractors that are installing RG6 quad-shield coax and it HAS to have an outer shield/braid that consists of either bare copper or tinned copper, it cannot be aluminum.

They install this stuff in homes, apartments, and condos.

I'm trying to find out where I can get this stuff at an extremely cheap price. A few of these contractors are finding it at $59 per 1K. :confused: I mean, obviously this is made over-seas and probably is a piece of junk, but does anybody know where I can go?

Jason:

You are correct, quad shielded RG6 can't be sold at those prices. I agree that it's probably imported stuff.

The only place that I have seen prices like that are on e-bay. Maybe they bought a bunch from someone working for the cable TV company who stole it? Just a guess.

You might want to see if you can hook up with Tele-Data Express in Arkansas. Try contacting them at [email protected]. Maybe you guys can work something out.

Thank you sir. I will definitely look into that.

I have some resi. contractors that are installing RG6 quad-shield coax and it HAS to have an outer shield/braid that consists of either bare copper or tinned copper, it cannot be aluminum.

Who is requiring this?

-Hal

Every one of them requires quad-shield.

Only one particular one has asked for the copper braid.

Every one of them requires quad-shield. Only one particular one has asked for the copper braid.


I know, but WHO is telling THEM that's what they have to use?

My point is wherever this requirement is coming from (I have a hunch its the cable company) want's quad shield or quad shield with copper braid for a reason yet they can't be too smart if they are letting this off-shore junk be installed instead. Normally they would spec Times or CommScope. Maybe you ought to find out who these guys are working for and "mention" this to them.


-Hal

Is this the 90 percent copper braiding that is asked for? I think HomeDepo sells a RG6 for $59 per 500 ft. reel,but i don't think its more than 60 percent braid. Comcast uses a quad 6 with very high braid content in my area,----------John

I agree with Hal.

Who is asking for this and why?

RG6 Quad is understandable. Having copper shield there is no reason for it. You can get RG 6 quad for 59.99. But it has a 18 awg copper clad steel wit 60% braid and 100 % foil. Also the company is for Installers only.

Bare copper would be a mistake. I think whoever is asking for this doesn't not know what he/she is talking about.

I agree. I have never seen a CATV cable with copper braid. The old legacy RG spec cables yes, but don't expect to find that with more than a single braid shield or be suitable for this use.

The best you are going to do with a quad shield cable is 60/40 aluminum braid. There is a headend lashup cable that is 95/95 with a silver plated center conductor but you wouldn't want to pay for it.

-Hal

Do you guys think quad shield is really necessary?

It's not very popular here in my area except for the guys that push the "smart home" structured panels.

All the cable companies here use commscope and they provide it free to the builders. I tend to stick to Belden with T&B snap & seal ends, but never quad shield.

It depends on the CATV system and it's proximity to such things as airports. I too agree that its probably overkill in 99% of the cases even where the CATV companies spec it.

And as for those "Smart Home" guys, enough said.

-Hal

Quad shield is preferred for satellite TV so it's not a bad idea to use it. Is it necessary? Probably not.

Does DTV and Dish-net actually use it? I know the DTV installation kit includes normal RG6.

The two Canadian satellite, factory install technicians don't use it here.

Not really sure. I was just trained that way. We use QS when we can just in case. Probably overkill.

RG6 quad is recommended for Satellite installations. I have had several people have power issues with less than RG6 Quad. Don't know the reasons but they just do. All satellite companys around here use Quad shield and advises everyone else to do so as well.

Never seen QS used for sat, I can see no reason for it either. If you are having "power problems" its because of something else. Try a cable with a solid copper center conductor rather than copper plated steel. Also check the DC resistance of your connectors to the shield. It just might be that the connector makes better contact with QS shields than single ones.

-Hal

I agree, QS isn't going to help your signal or power loss issues, it's only going to help keep stray interference from entering it.

I have never seen a satellite installation with an interference problem due to something radiating into the coax. CATV and off-air systems, yes, maybe due to the frequency differences?

Yes to works both ways but usually its radiation or leakage that they are concerned about. Systems use the same frequencies as a great may terrestrial communications services. Big problem if the system is using air navigation frequencies, they are near an airport and they have leakage.

-Hal

A customer of ours put a 2 story addition on their building. We did the wiring for voce, data and SAT tv. SAT has a RG6 quad sheild home run from dish to basement. Another RG6 QS home run from basement to second floor to connect to SAT equipment. Direct TV is the provider. Every thing worked fine for about 5 months and then just quits. Direct TV comes out and says the problem is with the wiring. I go out, break the connection in the basement and meter out the cable form second floor to the basement, its shorted. Replace the F connectors, still shorted. Run new RG6 QS. Still not getting signal from the dish. Direct TV comes out and says the new cable will work but will fail again because it does not have a solid copper center conductor. That when you change chanels the converter sends a signal, with 13 to 18 volts to the dish and over time this voltage will cause the copper clad center conductor to fail (melt??)
Does this sound correct?

Its got me baffled. Thanks,
Steve

No.

The LNB (or multiswitch and LNBs) is powered as he says from the receiver through the coax. That same voltage also serves to tell the LNB or multiswitch whether to send down on that one cable the right hand polarized or the left hand polarized signals by changing back and forth from 13 to 18 volts as you go through the channels. (The RH and LH signals are duplicate frequencies so they cannot be on the one cable at the same time.) The LNB doesn't care whether it gets 13 or 18 volts for power.

That said, this is one instance where power is carried by the coax in addition to the RF signal. Its understandable then that you would want to keep the DC voltage drop on that cable within acceptable limits. That is not something you would be concerned about with coax running to an antenna or a CATV drop and wiring in a building because it doesn't handle any power.

Most coax has a center conductor that is made of steel that has a thin layer of copper plated on the outside (called "copperweld"). The steel is used for strength and the copper provides conductivity at RF frequencies because of the "skin effect". The skin effect says that the higher the frequency the more to the outside of a conductor the signal will travel. Therefore at CATV and higher RF frequencies the signal travels entirely on the outside of the center conductor through the copper plating. So using a solid copper center conductor for a cable that only handles RF is also a waste of money.

What happens when you use a cable with a steel copperweld center conductor to handle power also? As said, when it has to handle any current you need to be concerned with making sure that what ever is on the other end gets ample voltage to operate. If you look at the DC resistance specs for a copperweld cable vs a solid copper center conductor, the solid copper obviously will be lower due to the fact that copper is a better conductor than steel.

What does this mean? Really not much unless you are installing long runs where voltage drop becomes a factor. Then you would want to use a solid copper center conductor.

As far as a copperweld center conductor causing the cable to short, think about it. The center conductor would have to somehow contact the shield through the dielectric that separates the two. Usually this happens because of a staple shot through the cable. The cable can work for awhile then fail. But lets say there were no staples used. Could the center conductor become hot enough because of the current to possibly melt through the dielectric? Nope. Even with a dead short at the LNB, the receiver LNB power is current limited to probably no more than 250ma. That would hardly cause even an 18 ga steel wire to get warm.

What would cause the cable to short? An improperly grounded dish and lightning is the first thing that comes to mind. Wouldn't even have to be a close strike. Then comes crummy cable itself, as well as water migration within the cable.

If you really want to know remove the shorted cable and start examining it. Look for the obvious stuff first like pinholes, staples, etc. Then start cutting it into sections and using your ohmmeter until you find the shorted section. Then cut that apart to see what is causing it.

-Hal

Well, I've learned more about Coax cable in the last minute right here than in the last 5 years :bow: :bow: to Hal. That is why I love this board!!

I have seen a lot of this. Using coax ends that aren't sealed allows water into the coax and it sits there at the low spot. I have actually seen a center conductor totally corroded off due to water.

I have also removed coax and held it differently (upside down) and had water pour out like a garden hose.

Hal - thanks for the very informative reply. I know that there were no staples involved in this installation. These 2 cables were the last to be run and were tie wraped to other existing cable runs. When I'm in the area I'll look at/for grounding issues. Thanks again. This is such a great place for information of all types.

Steve

Here I go!

Steve,

Hal is RIGHT ON with his information here. I would like to add a few things to his comments.

I have worked with coax installations since the early 80's when 23 channels on CATV or 300mhz was about it. A lot has changed since then. But is seems some "Sparkies" still resort to substandard specifications.

The weakest link in a coax installation is its connectors/connections. With frequencies reaching the 1-Gig mark on Cable TV, and 2-Gig for Satellite, your connectors must be top-notch and terminated correctly.
This is why they make proper "Stripping" tools for all sizes of coax. If "Sparky" is still using a razor knife or even his pocketknife, he is probably "Scoring" the skin of the center conductor causing the signal to have to jump over the scratch. This can cause major signal problems. Also, use a good quality connector, and always tighten all outdoor connectors with a wrench.

Hal is also correct about a short causing the center conductor to melt. WHAT??? :rofl: There is no way. We install Commercial Direct TV here in Jacksonville, FL. and I have never seen or heard that one. Lightening, Yes could be, but we have dishes on the roofs up to 36 stories high, and never have service calls for lightning hits. Most of our grounds are done in the communications closet where our multi-switches are located, using ground blocks.

From your post, I am assuming there is only 1 TV off of this dish? You are testing the cable from the basement to the receiver? Did you disconnect the receiver before you tested? Could it be possible someone has come in behind you and thought they could spit off your cable to another TV? A splitter can cause or act like a short when doing a continuity test. Have you tested the voltage output of the receiver to make sure it’s not faulty? Are you using any Diplexers, and if so, are they connected properly?