RG 11 cable for internet?

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Stevenfyeager

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United States, Indiana
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electrical contractor
A customer told me his internet company recommends RG 11 to be run in his business. I can't find it to buy. Is it necessary to change from RG 6 ?
Thank you for answering my questions, I am still new and don't know how to post thanks for your posts. Thank you!
 
They make RG 11 but I think that is what the utility uses.

RG11 cable is made for special purposes like burial or very long runs. It's so thick that it needs special connectors and is very hard to bend. It's a real pain to use and isn't recommended for most indoor installations.
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Stevenfyeager said:
... I can't find it to buy. Is it necessary to change from RG 6 ?...
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Where are you looking to buy from? It's readily available through internet sales.

RG11 has better transmission characteristics, but it isn't as flexible as RG6 (and on average costs more per foot). Don't have enough info to determine if it is necessary. You should talk with the internet provider directly.
 
Smart $ said:
Where are you looking to buy from? It's readily available through internet sales.

RG11 has better transmission characteristics, but it isn't as flexible as RG6 (and on average costs more per foot). Don't have enough info to determine if it is necessary. You should talk with the internet provider directly.
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There are two different commonly used types of coaxial cable. One type (including RG-6), used for CATV, video and most RF purposes has a characteristic impedance of 75 ohms.
The other type, including RG-58, used for some instrumentation and for thin net Ethernet and has a characteristic impedance of 50 ohms.

If you use a 75 ohm coax for 10BASE2 (thinnet) Ethernet, the termination resistances will be wrong and there will be reflections that will reduce performance.
Both RG-6 and RG-11 are 75 ohm coax, so neither of those are suitable for Ethernet. They are both OK for video and some other forms of data, but the correct termination resistors must be used.

If you use 75 ohm cable with 75 ohm terminations for Ethernet, you will probably be OK, but you will be in technical violation of the standard, and if someone mixes lengths of 50 ohm cable in as patch cables or jumpers you will have serious problems.
 
GoldDigger said:
There are two different commonly used types of coaxial cable. One type (including RG-6), used for CATV, video and most RF purposes has a characteristic impedance of 75 ohms.
The other type, including RG-58, used for some instrumentation and for thin net Ethernet and has a characteristic impedance of 50 ohms.

If you use a 75 ohm coax for 10BASE2 (thinnet) Ethernet, the termination resistances will be wrong and there will be reflections that will reduce performance.
Both RG-6 and RG-11 are 75 ohm coax, so neither of those are suitable for Ethernet. They are both OK for video and some other forms of data, but the correct termination resistors must be used.

If you use 75 ohm cable with 75 ohm terminations for Ethernet, you will probably be OK, but you will be in technical violation of the standard, and if someone mixes lengths of 50 ohm cable in as patch cables or jumpers you will have serious problems.
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RG-8 is also a 50 ohm cable and can be used for longer distances than RG-58.
 
GoldDigger said:
There are two different commonly used types of coaxial cable. One type (including RG-6), used for CATV, video and most RF purposes has a characteristic impedance of 75 ohms.
The other type, including RG-58, used for some instrumentation and for thin net Ethernet and has a characteristic impedance of 50 ohms.

If you use a 75 ohm coax for 10BASE2 (thinnet) Ethernet, the termination resistances will be wrong and there will be reflections that will reduce performance.
Both RG-6 and RG-11 are 75 ohm coax, so neither of those are suitable for Ethernet. They are both OK for video and some other forms of data, but the correct termination resistors must be used.

If you use 75 ohm cable with 75 ohm terminations for Ethernet, you will probably be OK, but you will be in technical violation of the standard, and if someone mixes lengths of 50 ohm cable in as patch cables or jumpers you will have serious problems.
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GoldDigger said:
RG-8 is also a 50 ohm cable and can be used for longer distances than RG-58.
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Who said anything about ethernet?


And we're only discussing RG11 vs. RG6.... ???
 
Smart $ said:
Who said anything about ethernet?


And we're only discussing RG11 vs. RG6.... ???
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Well, it mentioned "internet company". If the provider wants broadband cable internet connectivity, then 75 ohm would be appropriate. But it is not clear from the OP that that was what was intended.
 
GoldDigger said:
Well, it mentioned "internet company". If the provider wants broadband cable internet connectivity, then 75 ohm would be appropriate. But it is not clear from the OP that that was what was intended.
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Already knowing what you pointed out, I didn't interpret the purpose as anything other than.
 
You will also need new tools to work RG 11. There are many different RG cables-- 58,59,6,8, 11 are just some of them. Personally I have never worked with anything larger than RG 6. Even in very large homes (12,000 sq.ft) I have only seen RG6.

Talk to the company you are going to install this for and see what they are looking for.
 
Dennis Alwon said:
You will also need new tools to work RG 11. There are many different RG cables-- 58,59,6,8, 11 are just some of them.
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And then, some people use the RG terms generically. Some people will ask for RG59 as a 75 ohm coax for inside distribution of CATV; RG59 is pretty ratty for that but is OK for baseband video (although there are better ones). -6 and -11 have different frequency/loss profiles. Etc. I always ask for what they're putting on the wire and for what distance, then select the appropriate cable. Some cables don't use even RG designations (i.e. Belden 9281 for baseband video, 1505a for SDI video, etc) even though they might fit the loose RG spec.

The other question is "Does it matter?" 20' of RG-6 from a building entrance to a modem isn't going to make any difference unless the signal is so marginal -at- the entrance that it shouldn't be accepted at all. OTOH I wouldn't use the stuff for a 20 story building distribution system.

(BTW, my broadcast engineer friend was showing off the new Belden one-piece crimp BNC connectors for 1505a. Really nice.)
 
zbang said:
(BTW, my broadcast engineer friend was showing off the new Belden one-piece crimp BNC connectors for 1505a. Really nice.)
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Just as a side note, the connectors are not just sized to fit the mechanical characteristics of the cable, they are also internally designed for a transmission line impedance of either 50, 75 or 90 ohms to match the characteristic impedance of the cable.
 
GoldDigger said:
Just as a side note, the connectors are not just sized to fit the mechanical characteristics of the cable, they are also internally designed for a transmission line impedance of either 50, 75 or 90 ohms to match the characteristic impedance of the cable.
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Yep. I can't count the number of 50 ohm BNCs I've seen on 75 ohm cable. Doesn't actually matter for many things, but it's still sloppy work. Using the proper tooling and connectors is part of the job, just like using the right size wire nut or box connector.
 
GoldDigger said:
Just as a side note, the connectors are not just sized to fit the mechanical characteristics of the cable, they are also internally designed for a transmission line impedance of either 50, 75 or 90 ohms to match the characteristic impedance of the cable.
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For my education, can you give me a quick explanation of what the characteristic impedance of a type of cable is a measurement of? Is it an impedance/resistance per some unit length, and is it related to the parallel capacitance between the interior conductor and the shield and/or the series inductance of the conductors?
 
ggunn said:
For my education, can you give me a quick explanation of what the characteristic impedance of a type of cable is a measurement of? Is it an impedance/resistance per some unit length, and is it related to the parallel capacitance between the interior conductor and the shield and/or the series inductance of the conductors?
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Basically it is a function of the relationship between the per length capacitance and per length inductance. It has no DC component. You change the characteristic impedance by changing the size of the center conductor (inductance) and/or the distance and dielectric between center and outer (capacitance).

The reason that it matters is that if you have a long transmission line and terminate it with a resistor whose value is the characteristic impedance there will be no reflection. If the termination is a higher resistance there will be a reflection that is in phase with the incoming signal. If it ls less than the characteristic impedance then there will be a reflection that is opposite in phase to the incoming signal.
With either an open circuit or a short circuit the amplitude of the reflection will be the same as the amplitude of the incoming signal.
 
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As others have said RG11 is a much thicker cable that requires special connectors. It will transmit more data than RG6. However I'd be surprised if a very good RG6 like Belden 6194a or 7195a isn't enough. FYI Belden makes very good cables you can find an authorized seller here: http://www.belden.com/resourcecenter/salesandsupport/distributors/locator-dis.cfm And if you're confused, call up Belden. They can be very helpful.

I've had a good experience with https://www.anixter.com/en_us.html.

http://www.bluejeanscable.com/store/sdi-cables/index.htm and others have good info on Coax. I know more about wiring than running Coax. Other here with more Coax experience may chime in.

Stevenfyeager said:
A customer told me his internet company recommends RG 11 to be run in his business. I can't find it to buy. Is it necessary to change from RG 6 ?
Thank you for answering my questions, I am still new and don't know how to post thanks for your posts. Thank you!
Click to expand...
 
ggunn said:
For my education, can you give me a quick explanation of what the characteristic impedance of a type of cable is a measurement of? Is it an impedance/resistance per some unit length, and is it related to the parallel capacitance between the interior conductor and the shield and/or the series inductance of the conductors?
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There is a pretty good discussion at http://en.wikipedia.org/wiki/Characteristic_impedance
The bottom line is that for an ideal transmission line (zero resistance, no dielectric losses, etc) Z0 = sqrt(L/C) where L and C are the values per unit distance. (Since they are divided, it does not matter what unit of length you use.)
 
dylanmitchell said:
As others have said RG11 is a much thicker cable that requires special connectors. It will transmit more data than RG6.
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It will not transmit "more data". It will however carry the given signal with lower losses. At 700Hz, generic RG6 loses about 5.6 dB/100 ft while RG11 is more like 4.7 dB. It adds up.

(Also, it doesn't require special connectors, it requires specific ones for that size and impedance, just like almost all coax.)
 
When I have used RG-11 it has been used on very long runs for satellite, like when going over three hundred feet. You can get it copper and copper-clad AL and the copper clad is useless from what I've observed. I used to buy it from Perfect 10 they sell satellite system components and cable but I'm sure almost any electrical distributor could get it.
 
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