Suggestions For a Coax-To-Ethernet Solution?

watanabe writes "I just moved from a house with Cat5e wiring to a house with ... a whole bunch of coax cables. Like, my living room has five coax cables coming out of a hole in the wall. All of them go back up to my attic. The house is big, (and I like it, thank you), but I have realized that our digital usage pattern (media server + squeezeboxes + remote time machine backups to a linux box) will not work without wiring. I am currently bridging some old Linksys WRT54Gs to the right places, but of course, that slows everything down. This got me thinking: 100mb ethernet is four wires, yes? And I have four wires for every two coax cables. What about a two coax-head -> ethernet jack setup? Has anyone done this before? Searching online only gives me $100+ coaxethernet transceiver type boxes. At that price, a HomePNY system would make more sense. I'm willing to solder if I have to, but I first wanted to get advice and holes shot in my plan, if there are any."

Comments

Use the Coax as a wirepull for the cat5

[mtippett]

If you have lots of coax running through pipes and if it is free, then use the coax as a wirepull to rewire the house.

Cat5 provides many more options than cat5.

Re:Use the Coax as a wirepull for the cat5

[0racle]

Actually, I have found that Cat5 provides just as many options as cat5.

I admit though, my testing may not have been exhaustive.

Re:Use the Coax as a wirepull for the cat5

[UID30]

If the coax was installed when the house was built, then the coax is probably stapled to the wall studs. If the coax was installed "after-market", then this trick might work.

</2cents>

Re:Use the Coax as a wirepull for the cat5

[Afell001]

Do this and run new Coax alongside, as well as a slip line for any future wire pulls you may have in mind. Just be aware to use duct tape liberally and if you don't mind the mess, some line-pull lube would go a long way for tight fits. You can then put a punch-down in the attic and run patch cables from the punchdown into a switch in the closet in the floor below the attic. I recommend that if you get a 12-block punchdown (should be relatively cheap), then run all twelve patch cables down to the closet, even if you are only using half of them. It will save you some work later on.

Also, check building code in your area, as you may have to buy plenum insulated Cat6e as opposed to the cheaper PVC. Some jurisdictions actually restrict the use of PVC, even when it is behind a wall.

I went through and did this for a friend quite a few years ago (replaced all his phone cabling with Cat6e) and had an electrician friend of mine give us advice before we started. The electrician said we were OK to run the cabling ourselves, but we had to use plenum since that was what code required. The cabling was twice as expensive as PVC, even when bought in bulk. We also ran slip lines, which has been a god-send for my friend since he had to then follow up a year or so later and run more lines through to his home theater.

Re:Use the Coax as a wirepull for the cat5

[gyrogeerloose]

You do realize ethernet originally ran over coax, right? Google '10BASE2'

Only problem with that is 10Base-2 ran over 50 ohm impedance coax while CATV coax is 75 ohm impedance. The mismatch would reduce the power delivered to the receiving end and set up a standing wave that would deform the wave shape, possibly causing errors.

Re:Use the Coax as a wirepull for the cat5

[TrisexualPuppy]

It became unpopular when it became too expensive to use. It was always expensive as that is the nature of coaxial cable, but when UTP became deployed, it was more and more and more realized that there was no need for coax and its terminations. Coaxial cable works beautifully up to high frequencies in the units or tens of GHz, but twisted pair is just as good into the hundreds of MHz. When your baud rate isn't going to exceed that, why mess with something more expensive?

As for the question posted by timothy, it is by another slightly electronics-illiterate poster. The statement, "This got me thinking: 100mb ethernet is four wires, yes? And I have four wires for every two coax cables. What about a two coax-head -> ethernet jack setup?" needs to be examined here. You can't just assume that since Ethernet "is four wires" you can use any four conductors as a layer 1 transport. That might bring house electrical wiring into the equation. No, we can't do this since we are talking about transmission lines, and everything has to be impedance matched, and the PHY has to be able to handle what the symbols look like on either end of the line. We aren't talking DC here--there is a lot more involved to high speed communication links than "wiring stuff up." ;)

So, I would either go with a coaxial media adapter or use the coax to do new Ethernet cable pulls.

Re:Use the Coax as a wirepull for the cat5

[lewiscr]

Attach a CAT5/6 AND a string, and pull like hell. You'll be glad you have a string in the wall when you want to pull CAT7.

Just remember, when you attach something to the string, always attach a new string too. It sucks when you finally finish pulling a run, only to have forgotten the replacement string.

Re:Use the Coax as a wirepull for the cat5

[StikyPad]

Cat5 can do better if you coax it.

Re:Use the Coax as a wirepull for the cat5

[Hognoxious]

You do realize ethernet originally ran over coax, right? Google '10BASE2'

Yup, and guns used to load the bullet from the same end it shoots out of.

Re:Use the Coax as a wirepull for the cat5

[mini me]

And cars use to run on electricity... oh wait.

Re:Use the Coax as a wirepull for the cat5

[Hognoxious]

It's a bitch to try to crimp Ethernet without the right tools, and those will set you back a couple of hundred dollars (for the good ones).

The crimping pliers I use cost about ten bucks, and I've produced one bad cable out of twenty - and that was the first one I'd ever made. When that happens you cut off an inch and redo.

Plus, if you're installing it fixed to a wall you'll likely use box sockets. The terminals on those are usually screw fit.

Re:Use the Coax as a wirepull for the cat5

[JamesP]

I'm gessing you can get a Monster Cat5 cable for an absurd amount of money, that's got gold plated connectors and electrolytes and stuff...

Re:Use the Coax as a wirepull for the cat5

[tweak13]

That's not the way it works. The value of characteristic impedance is in ohms, not ohms/meter. It absolutely does not change based on cable length. It describes how signals will propagate which is a characteristic of the cable, not how long it is.

Re:Use the Coax as a wirepull for the cat5

[Nerdfest]

that's got gold plated connectors and electrolytes and stuff...

It's what networks crave!

ATT Uverse runs over coax

[your_mother_sews_soc]

I have AT&T's Uverse for phone/TV/internet and its set-top boxes communicate over coax. They are using IP over coax, since the router shows the boxes' IP addresses as though they were on a an Ethernet network. The boxes run Windows Media Edition, for what it's worth.

Re:ATT Uverse runs over coax

[your_mother_sews_soc]

sorry, I realize my post contributed nothing.

Re:ATT Uverse runs over coax

[Anonymusing]

sorry, I realize my post contributed nothing.

This may be the most profound comment I've ever read on Slashdot.

Re:ATT Uverse runs over coax

[mcgrew]

Yes it did -- it gave me an idea. I don't know if it would work, but maybe he could use cablemodems to connect ethernet to the coax. Of course, he probably doesn't have enough cablemodems laying around, but if he does, or can get a cheap supply of used ones it might work.

Re:ATT Uverse runs over coax

[Anonymusing]

And with that, we complete our tour of Slashdot.

Twisted pair, man

[Spy Handler]

100mb ethernet is four wires, yes? And I have four wires for every two coax cables.

The four wires in your coax are not twisted. It's not gonna work.

Pay $100 for those coax-ethernet transceiver things, or string some Cat5e. Seriously, if you can afford to buy a big ass house then what's another couple hundred??

Use the Coax to pull CAT 5e cable

[Cassini2]

If the coax is sitting loose in the walls, you can use it as a pull cable to thread in replacement UTP cable.

Old Ethernet worked over Coax. I just doubt you have the correct kind of Coax. Also, my experience with residential cable installs is that they tend to have damaged Coax cable, so it is pointless even trying to use it for high-bandwidth applications.

Finally, while it is theoretically possible to substitute 4 "pairs" of twisted pair with 4 Coax cables, my suspicion would be that you would have severe impedance mismatch problems. It might be good at 10 Mb, where the old Coaxial ethernet worked. I doubt it would handle modern 1 Gb Ethernet signals. Also, modern Ethernet expects all 4 pairs to be of approximately the same length, and it is unlikely someone would have 4 matched-length pairs of coaxial cable sitting in their wall.

MoCa

[MikeDataLink]

I'm surprised no one has already mentioned MoCa,. Several companies make MoCa adapters that runs 100Mb/s ethernet over Coax cables: http://www.google.com/products/catalog?q=MOCA+adapter&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&cid=2590185696454305965&ei=PoR9S5uIC4mWtge8z5GfBQ&sa=X&oi=product_catalog_result&ct=image&resnum=1&ved=0CBQQ8gIwAA# And read all about it on Wikipedia: http://en.wikipedia.org/wiki/Multimedia_over_Coax_Alliance

Re:10Base-2?

[Lumpy]

yes it does. you impedance match the ends with baluns.

I did that a LOT back in the day of 10base2 when the office owner would not pony up for running wires.... yet he paid 2X that for baluns and impedance matching...

Re:Related Questions

[Corf]

A conduit containing both CAT6 and some fishing line to pull through whatever's in vogue once CAT6 will no longer cut it.

Another alternative

[joeyblades]

How old is the house? It it's not too old, the telephone may be run on cat5. You can actually piggy-back ethernet and telephone on the same cat5 cable. I did that in a couple of rooms in my house and it worked great.

Wow... what are the odds

[litui]

I was just searching for this same thing today and a friend of mine suggested this product:

http://www.netsys-direct.com/proddetail.php?prod=NH-310CEKIT&cat=27

It's a 200Mb ethernet-over-coax solution that makes use of existing coax installs and uses traditional cable. We'll be testing it soon for a 200 metre install.

Re:That's not how coax works

[curunir]

Really? You might try telling that to Netgear or D-Link or any of the other companies that make Coaxial Ethernet Bridges.

This whole story could have been avoided if the poster knew the right term to Google.

Re:Related Questions

[jayteedee]

I disagree on the conduit containing Cat6 and the fish line. I'd keep the Cat6 separate and put in the conduit with the fish line though. Conduit is definitely the great idea, but having to run more than 1 cable through a conduit is a lot more work than an empty conduit. And forget running the gray PVC or the flexible gray conduit (outdoor rated stuff). Both are way too expensive and totally unnecessary for low voltage wires (except maybe in a few weird states with goofy regulations). Use cheap polyethylene tube used for sprinklers (1/2") which you can get in 500 and 1000 foot rolls.

CATV is cat5 in Roman

[mangu]

To use CATV cable for cat5 all you need to do is you run X-Base-II with L ohms terminators. Or would those be LXXV ohms?