wiring the wireless.
March 1, 2011 4:57 PM   Subscribe

TechFilter: help me out moving/rewiring my wireless antenna.

I think I know what I'm doing, I just need confirmation, and make sure I have the lingo right before I head out and buy stuff.

Our internet service is described as "broadband wireless". I'm not sure what the exact technology is, it isn't WiMax because I know that's what we're upgrading to in the future. We have an unpowered directional antenna (a rectangular grey box) pointing towards the nearby mast (which is about 2 km away) and a small powered unit (only about 5cm by 3 cm by 1 cm) sitting between the wall jack and the router. Not sure what that does.

My issue is the wall jack is in the wrong room, I want to move it to a new room. I can easily do the wiring, I just need to get the details right. It looks a lot like coaxial cable, can I assume it is and use more of that (which is basically TV antenna material available anywhere)? Are there material quality differences?

Can I split it and have two wall outlets (both existing and new), or should I only have one? If splitting, can I just use a 75 ohm TV antenna splitter available cheaply? I don't think a powered/amplified splitter would be wise, would it? If split, I'd not be attempting to use them simultaneously.

Is there a limit to the length I could run the new cable? It'll be under the house, about an extra 8 metres.

The wall jack, looks to me (from memory, it's not in front of me) like an RJ-45 type thing, the sort you plug an ethernet cable into. I don't imagine I'll have trouble wiring that.

Thanks for your insight.
posted by wilful to Technology (5 answers total)
Best answer: Can you take pictures of your setup? It's not clear what kind of cables are coming into and out of the 'small powered unit', your router, and the wall jack.

The cable coming from the antenna is coaxial, but it is almost certainly not the type that TV signals go over. If you use cable meant for TV or any kind of splitters at all, you'll probably get a lot of signal loss and your setup may not work at all.

Basically, with any kind of wireless equipment, you want to keep the analog runs (the stuff on coaxial) as short as possible to reduce the amount of loss. If you want to extend your signal, extend the ethernet portion.
posted by zsazsa at 5:15 PM on March 1, 2011

Best answer: It looks like your ISP uses the same technology as mine. Up on the roof (our anywhere outside with line of sight to the nearest transmitter) is a receiver -- it used to be a square-shaped box like yours, about 7-8 inches per side, but then they upgraded it to something that looks like a tiny satellite dish (also about 7-8 inches, diameter) when I wanted to move up to faster speeds.

Coming out of there, and all the way into the house, is an Ethernet cable, which then plugs into a small box just as you described. It has two RJ45 jacks -- one takes power from your household current and shoots it back up to the antenna up on the roof (power over Ethernet), and the other is a regular un-powered Ethernet connection which you can put into your router or straight into a desktop or laptop computer.

The technology is theoretically capable of very high bandwidth, though it's pretty rare that ISPs will offer it. (Mine does, to businesses, but it's obscenely expensive.) Latency's really good, and it's basically on par with good cable service. Plus, in my case, it's locally owned, rock-solid reliable, and maybe most important of all, keeps me out of Comcast's grubby hands.

Anyway. I don't know what it's called, but you're right -- it's not WiMax. The cable isn't coax (at least not in my case); it's pretty typical Cat5e throughout, from what I can tell (except that it seems unusually thick in the part coming down from the antenna). You MAY want to check with your ISP, but I think you may be able to use any Cat5e or better.
posted by CommonSense at 5:45 PM on March 1, 2011

Best answer: I would recommend contacting your ISP for advice if you want to change anything about your antenna lead.

There are many different varieties of coaxial cable. I would guess that the kind used in this application is low-loss 50-ohm coax. Coax used for TV typically has a 75-ohm characteristic impedance and is designed for different frequencies.

I agree with zsazsa about extending the Ethernet portion, if you can.
posted by UsernameGenerator at 7:13 PM on March 1, 2011

Best answer: Could be 900mhz Ethernet, I used to have that set up between my home and office 1m away using a directional antenna. Was called wavelan, or at least that was the trademark name.

You should not split it, but if I can think outside the box here for a second - why mess with the coax at all? If the wall jack is standard rj45 Ethernet why not just run Ethernet cable from that jack to where you want the new jack to be? Put a small notch in the wall plate so you can run the new cable through it and run the other end to your new destination. If you ever want to go back to using that jack you just unplug it.

Or push the jack and new cable into the walk and cover it with a blank plate.

It's not quite as pretty as the other solution but you're not guessing about the cable and wondering if it's gonna work.
posted by phearlez at 7:27 PM on March 1, 2011

Response by poster: Thanks for replies folks. After speaking to my ISP (where I guess I should have started), the cable to the antenna is Cat-5 ethernet, outdoor grade. I could simply rewire some more cable and click the new cable in to the antenna. Too easy.

The small thingy between the wall jack and the router is designed to power the antenna.
posted by wilful at 8:33 PM on March 2, 2011

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