Slashdot Mirror
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."
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>
"Glory is fleeting, but obscurity is forever." - Napoleon Bonaparte
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
Mike @ The Geek Pub. Let's Make Stuff!
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.
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...
Do not look at laser with remaining good eye.
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.
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.
This ain't rocket surgery.
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.
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.
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.
I send you this message in order to have your advice.
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.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
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.
"Don't blame me, I voted for Kodos!"