Ask HN: How should I make a point-to-point wireless home system? | Hacker News Reader

Ask HN: How should I make a point-to-point wireless home system?

11 pointsivankirigin15 comments

This is a problem I think a lot of people have, including some smart hackers I know:

Your internet connection is at location X, and you want it at location Y. Wifi router at X and receiver at Y is okay for some applications, but the signal can get week if you're passing through lots of walls or floors. Also, if you're, say, streaming to an X-Box or a desktop PC used for gaming or streaming movies, a hit in speed is really noticeable.

Using a hard wire is great, but hard. Who wants to dig into walls or have lots of wires around?

Setting up wireless routers to act like repeaters or access points seems arcane, with questionable benefits.

So I thought I'd ask the smart folks here: how should I do this? If I really just want the X to Y speed maximized, is there good specialty hardware for this? Any hacks to take off the cap on broadcast strength on an easily available router?

[edits: - Ethernet over power is horrible in my experience. I don't even think there is a connection between the two spots

- Laying down line is untenable currently because it is a rental, and the situation is dire: separate back office (converted garage) to a living room in the house. I won't dig into concrete and most certainly won't drape wires.

- Why isn't this just a product? Two routers with directional antennae + N repeaters long the route? ]

Any hacks to take off the cap on broadcast strength on an easily available router?

Yes, with certain firmwares you can. This adjustment is like turning up your stereo: it might get a bit "louder" but beyond a certain point it begins to clip and distort. The big difference is that unlike a stereo, the default radio gain is usually set fairly high -- there's rarely much more headroom to get.

A radio tuned for 100mw might have 200mw in it, if you're lucky. While this sounds like a lot, it's only 3db, which is a small fraction of any signal meter "bar" reading.

If you really want to increase your effective transmission power, your best bet is a high-gain antenna:

http://tinyurl.com/client-antennas (no affiliation)

These will increase your effective signal strength by focusing the beam of the antenna in the direction you wish to transmit/receive it. The down side is that the antennas have to be pointed at each other, and the higher the gain the closer they have to be aligned.

However, please keep in mind that increasing your effective radiation in one direction above the initial design limit is likely to run afoul of your government's (the FCC in the USA) rules about RF emissions.

In summary, yes you can do it, but it will take expensive, fidgety antennas, is probably illegal, and at the end of it you still might not get the amount of gain you need. I recognize your desire to use wireless but generally IMO it's not worth the work.

Most often you don't want or need to increase your transmission power. What you are looking for is a better signal to noise ratio (often written as SNR, S/N). And a directional antenna will receive less noise from directions it's not pointed at.

To stay within the valid "effective" output power of your regulatory domain, you can lower the transmission power of the transmitter. Or you can spend your excess gain by adding a little of high-quality cabling that puts your antenna at a better suited location (but more often it will be easier to just move the whole WLAN router/card/dongle).

A "pringles-like" design made out of stainless steel toilet-brush holders that includes experimental and simulation results (in German): http://www.heise.de/netze/artikel/print/100565

Registered just so I could post it. Thanks for giving me the excuse.

If you're on Windows / OS X (and even under Linux, the Windows utility has a Gold rating in wine), I'd recommend the Airport Express: http://www.apple.com/airportexpress/specs.html

(The reason I mention the OSes is that it's got a software utility for configuration - doesn't have a web interface in the unit)

802.11n (and a,b,g too), out-of-the-box WDS, pretty rock-solid little boxes, Ethernet jack on each if you need to extend wired. Not much bigger than a power supply.

I've got 3 at my house for exactly the reasons you posted and routinely stream media from the upstairs AP through WDS to the downstairs unit or torrent with 200+ sustained TCP connections (and high turnover/churn) - it doesn't even bat an eye.

$99 USD a unit. A little pricier than your average home wifi router but well worth it (and if you're on Windows or OS X, you can stream music from iTunes to individual APs' audio out jacks or share printers from them as well). Highly recommend them.

Edit: And for those recommending dd-wrt / openwrt for WDS - don't you believe it. The people using it aren't putting any decent loads on it. I tried it (within this last year) before going all Airport Express. Too many issues with random reboots in the APs - the firmware stability on those projects isn't even remotely close to the Airports.

Did you consider homeplug networking?

I have two ZyXEL home plug devices and get ~ 60-70Mbps from them (they're rated at 200Mbps for the whole network you can add them as you go). They're pretty good, but latency is higher than I'd expected - ~4ms.

Why not use WDS on cheapo firmware-hacked routers, using dd-wrt/openWRT/freeWRT (I use Tomato)? If you really want speed, you may be able to find standard 802.11n routers that can do WDS, although if I really wanted speed I would (and do) use cable. These firmwares usually also allow wireless strength mods, although it may not be practial.

For info on WDS: http://en.wikipedia.org/wiki/Wireless_Distribution_System or: http://www.dd-wrt.com/wiki/index.php?title=WDS_Linked_router...

These used to be $50: http://meraki.com/ (This company grew out of the MIT Roofnet auto-configuring mesh technology)

Expensive, but these are what my dad's WISP uses: http://en.wikipedia.org/wiki/Motorola_Canopy They are not not mesh, and they involve config. You can buy them on licensed spectrum as well. Bulletproof, amazing range and bandwidth.

There is the Ethernet-over-Power option (they seem to work a lot lower than their rated speeds, but over longer distances / walls might be better in some cases compared to wireless). (Linksys PLK300, or D-Link DHP-301, etc).

Before shelling out that much, I would try getting a second router to act in client mode and have high gain or directional antenna on both routers.

Know of any good off-the-shelf directional antennae? Not sure I want to mess with pringles cans. Also, any guides on setting a direction through a few walls? Or do you just use it like a dowsing rod with some power sensor to point it in the right direction?

Also, I've tried a network-over-power system, and it totally sucked when it worked at all.

TigerDirect, surprisingly, has some decent directional antennas. I've had decent luck with http://www.tigerdirect.ca/applications/SearchTools/item-deta..., but http://www.tigerdirect.ca/applications/SearchTools/item-deta... looks pretty decent as well.

As for setting it up, I used it a pretty low-tech routine: set the antenna, walk around with a power meter, adjust antenna, and repeat. If you really want to get into it, put some thought into how the walls and other large objects are laid out, and take that into account when setting up your antenna.

I'm amazed someone hasn't made a 2 router + 2 directional antennae package for people like me. Thanks

dd-wrt lets you change the broadcast strength on some routers. check out their documentation for details - http://www.dd-wrt.com/

otherwise, unless you invested in commercial solutions (microwave transceivers), i believe you are stuck chaining together repeaters or running a cable.

I don't mind spending a bit for a low end commercial solution, as long as I'll spend less than, say, $800, and won't get cancer from sitting next to one for a long period of time :)

Got any links or brands?

If you're willing to pay $800, why not just pay someone to run a wire?

It's a rental and I'd rather have the equipment. I've lived in places where running a wire isn't really an option. I've done it myself before too, but that isn't even tenable. Also, I'd have to be pretty damn sure that I'm getting what I want for that money.

What cdr said. It's kind of difficult to tell what the constraints are - how big is the distance, is it your home or an office etc. We use ethernet-over-power-into-multilpe-wifi in my house and it works.

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