SceneryDriver
Senior Member
- Location
- NJ
- Occupation
- Electrical and Automation Designer
I'm sure your work and Home Depot connectors was the reason for that.
-Hal
Just goes to show that craftsmanship tops brand name in many cases.SceneryDriver
Quad Shield or Dual Shield RG6
- Thread starter infinity
- Start date
- Status
Just goes to show that craftsmanship tops brand name in many cases.SceneryDriver
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
What I'm trying to say is when someone pats you on the back consider the source before you take it as a job well done.
-Hal
-Hal
Are you using this cable for incoming service? I'm doing my house now I ran dual shield all over but I'm not sure what to run from my data closet to where the incoming service will be I'm thinking just running a cat6 and a coax to cover myself
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
That should do it. If it will be impossible to make any new home runs in the future, run two of each . . . or a conduit.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
There are many ways to configure the system so the pre-wiring can be tricky. In my situation tech just used the old cables to get the system up and running, now I need to run a few cables to the actual location where the equipment needs to be. For now I'll be running 3-RG6 cables from the splitter adjacent to the ONT to three new locations. One for the router, a second for an extender, and a third for the Fios One wireless TV/DVR system.
I may end up running additional RG6 cables to each TV location but with their new system this isn't necessary unless the wireless signal to the cable boxes ends up being too poor. I'll also need a Cat6 Ethernet cable from the ONT to the router for the WiFi.
For a new install I would run a raceway to each location as Larry suggested to future-proof the house.
The biggest thing with coax is using RG6 vs. RG95. The former has much higher bandwidth so even CATV is far cleaner. Coax has an upper limit on bandwidth that depends on design and also a characteristic impedance mostly 50 ohms. But since a lot of OTA stuff was originally designed for twin lead that is 75 ohms you see that on older setups. If the impedance does not match in the cable, connector, receiver, etc., you get a reflection which is signal loss. This matters far more than cable length or shielding.
The signal is high frequency so it actually runs along the surface due to something called the skin effect. If you have a signal on the center conductor and a foil shield you get an image signal on the shield. If it is braided which it often is for mechanical reasons it depends on the hole sizes. All dish antennas except the solid aluminum small ones have a porous mesh inside a fiberglass skin to make them light as well. If the hole size is less than 1/10th of the wavelength it is electrically opaque. Whether there are holes or not or even imperfections does not matter. This goes in both directions. A signal on the outside rides on the outside even in very thin foil and vice versa. The shielding from outside interference is called the Faraday effect or Faraday cage.
At DC or low frequency 50/60 Hz AC it rides in the cable. This is where extra thickness can help from a resistance point of view at long lengths if you can’t push enough power to the LNA/LNB. Important in SATV but useless in CATV at least at the residential end,
If you add additional shields at RF they do nothing at all.
Switching gears high voltage cable needs it. Above 2000 V power cables are shielded but for different reasons. At this point the goal is to make the flux on the insulation as even as possible. Unshielded cables tend to burn up if for instance the cable is accidentally laying against another cable or a grounded surface. A single shield does the trick and works just like coax up to 40 kV. Above that point they have to run 2 shields for 69 kV then more for 115 kV and so on. But obviously communication cables are nowhere near this.
CAT6 is an orphan that has gotten popular. CAT5E has a 100 MHz bandwidth. CAT6 has a 200 MHz bandwidth. Ethernet up to 1 gigabit is designed to work in 33 MHz bandwidth. It works just as good on 5E as 6. More bandwidth does nothing. The next standard up is 10 gigabit. Here we have a problem in that twisted pair won’t fix and the venerable RJ45 business line phone connector with its 250 MHz bandwidth is finally finished. We can go about 20-30 feet on CAT5E still just ignoring the losses but we are basically at the limits finally. CAT6 doesn’t increase the distance or anything at all. So we go to CAT7 which has very tiny coaxial cables and a couple competing connectors with extra pins in the corners of the RJ45 connector.
CAT6 is billed as future proofing. About the only advantage is it is more rounded so pulls are easier. The only thing it is future proofing since as I said the standards for communication skipped it is that it helps future proof Belden and Commscope margins.
If their cable quality is so awful that it needs 4 shields to do the work of 1 you may want to seriously consider a new vendor. There is a slight case for the mechanical strength of braided shielding and blocking microwave and cosmic ray signals in high RF environments on towers with lots of renters. But for home use? Don’t make me laugh. Single shield is fine. Just stop slamming the cable in the doorway you ran it through and stop using push on Chinese F connectors from Walmart and you’d be amazed. Or do what I did...I have many more channels, better quality, more UHD 4K etc. since I ditched cable and satellite and went pure Internet based distribution.
With using DSL or Cablemodrm as long as the SNR is high enough it doesn’t matter how high it is...it’s digital. The biggest problem is that with DSL the phone line was never intended to carry anything more than 4 KHz. Like 10 gigabit Ethernet what matters most is distance to the DSLAM (phone company’s transmitter). With cable companies bandwidth isn’t the issue but they are notorious for buying the cheapest cable available. Typically it only has an outdoor rating of 10 years before it should be replaced. Phone company cable was designed on a 50-100 year expected life. As cheap as they are I have no idea how cable companies stay in business. And that line is your problem. No matter how good your coax is, it isn’t rotting in the ground.
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The signal is high frequency so it actually runs along the surface due to something called the skin effect. If you have a signal on the center conductor and a foil shield you get an image signal on the shield. If it is braided which it often is for mechanical reasons it depends on the hole sizes. All dish antennas except the solid aluminum small ones have a porous mesh inside a fiberglass skin to make them light as well. If the hole size is less than 1/10th of the wavelength it is electrically opaque. Whether there are holes or not or even imperfections does not matter. This goes in both directions. A signal on the outside rides on the outside even in very thin foil and vice versa. The shielding from outside interference is called the Faraday effect or Faraday cage.
At DC or low frequency 50/60 Hz AC it rides in the cable. This is where extra thickness can help from a resistance point of view at long lengths if you can’t push enough power to the LNA/LNB. Important in SATV but useless in CATV at least at the residential end,
If you add additional shields at RF they do nothing at all.
Switching gears high voltage cable needs it. Above 2000 V power cables are shielded but for different reasons. At this point the goal is to make the flux on the insulation as even as possible. Unshielded cables tend to burn up if for instance the cable is accidentally laying against another cable or a grounded surface. A single shield does the trick and works just like coax up to 40 kV. Above that point they have to run 2 shields for 69 kV then more for 115 kV and so on. But obviously communication cables are nowhere near this.
CAT6 is an orphan that has gotten popular. CAT5E has a 100 MHz bandwidth. CAT6 has a 200 MHz bandwidth. Ethernet up to 1 gigabit is designed to work in 33 MHz bandwidth. It works just as good on 5E as 6. More bandwidth does nothing. The next standard up is 10 gigabit. Here we have a problem in that twisted pair won’t fix and the venerable RJ45 business line phone connector with its 250 MHz bandwidth is finally finished. We can go about 20-30 feet on CAT5E still just ignoring the losses but we are basically at the limits finally. CAT6 doesn’t increase the distance or anything at all. So we go to CAT7 which has very tiny coaxial cables and a couple competing connectors with extra pins in the corners of the RJ45 connector.
CAT6 is billed as future proofing. About the only advantage is it is more rounded so pulls are easier. The only thing it is future proofing since as I said the standards for communication skipped it is that it helps future proof Belden and Commscope margins.
If their cable quality is so awful that it needs 4 shields to do the work of 1 you may want to seriously consider a new vendor. There is a slight case for the mechanical strength of braided shielding and blocking microwave and cosmic ray signals in high RF environments on towers with lots of renters. But for home use? Don’t make me laugh. Single shield is fine. Just stop slamming the cable in the doorway you ran it through and stop using push on Chinese F connectors from Walmart and you’d be amazed. Or do what I did...I have many more channels, better quality, more UHD 4K etc. since I ditched cable and satellite and went pure Internet based distribution.
With using DSL or Cablemodrm as long as the SNR is high enough it doesn’t matter how high it is...it’s digital. The biggest problem is that with DSL the phone line was never intended to carry anything more than 4 KHz. Like 10 gigabit Ethernet what matters most is distance to the DSLAM (phone company’s transmitter). With cable companies bandwidth isn’t the issue but they are notorious for buying the cheapest cable available. Typically it only has an outdoor rating of 10 years before it should be replaced. Phone company cable was designed on a 50-100 year expected life. As cheap as they are I have no idea how cable companies stay in business. And that line is your problem. No matter how good your coax is, it isn’t rotting in the ground.
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hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
I'm sure you mean RG-59 which hasn't been used for CATV for at least a couple of decades. Back with 24 channel systems, with an upper frequency of maybe 250Mhz, it was the cable of choice. But today, with the upper frequency exceeding 1Ghz the loss is too much to be of any use.
Note also that actual RG cables date back to WWII with RG meaning Radio Grade. (There may be some controversy over what RG meant.) Original RG cable is still being made today with the RG designation printed on the jacket, however it doesn't find any use in CATV or even OTA because it's design is still the original single copper braid over a solid polyethylene dielectric and a solid copper center conductor. Because of the solid poly dielectric the loss is quite high. RG cables find there uses in baseband video. About the only place today would be CCTV camera systems.
The designers of the cables we use today kept the old familiar original size designations (RG-59, RG-6, RG-11, etc). We call a cable that is roughly the size of the old RG-6, RG-6 but that's really just slang for a cable that bears little resemblance construction wise and performance wise to the the original.
Coax cables can be had in many characteristic impedances. The cables we use for CATV and TV have always been 75 ohms. Back in the early days of TV 300 ohm twin-lead was popular because of it's ease of use, low loss and low cost. But that was replaced with RG-59 when the number of homes with multiple TV grew because it could be run within walls and around a house which you couldn't do with twin-lead.
Up until maybe 20 years ago you would still see TVs with 300 ohm screw terminals for the antenna input. We always kept a supply of 300-75 ohm matching transformers because they always were needed. I think I still have some someplace.
-Hal
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