Point to Point Wifi connections

Hi all,

I'm glad I found this forum and hope that you guys can help me answering some questions.

I have two projects for which I'd like to set up stable, point to point Wifi connections. One of them is "just across the street" to my neighbour over a distance of maybe 30 meters. The other is across half the town to my dad's office which is roughly 970 meters.

Both connections have clear visibility, so no obstacles are in the way. Also, for both connections I'd like a relatively high throughput. Latency is not super crucial, but I'd like to get a 100MBit/s throughput across the street and maybe 50MBit/s for the 970 meters thing - if that's possible.

Those should be "dedicated" point to point connections, so no regular "Access Points".

I've been searching the web for a while and found some people who have set up long distance Wifi connections and even put videos with in on youtube, but the technical details are spare. My questions would be:

1. What kind of hardware do I need? Should I take a standard cheap $40 802.11n router with a standard RP-SMA plug or do I need dedicated hardware when it comes to the actuall Wifi Transmitter (not the antenna)

2. Apparently, this is the crucial question: which antennas should I get?

3. The antennas have all kinds of different outputs (measured in dBi or similar). Do some of them come with an "Amplifier" that needs additional power? I find it hard to believe that a passive antenna can amplify a signal (unless it "channels" it by reducing the angle of transmission).

4. Could I mount those antennas indoors, e.g. behind a window, or would the glass already be too much of an obstacle for the connection?

5. How long can the antenna wire (the wire from the AP to the antenna) be at most? Is there a limit? I saw that many come with 3 meter wires. Could I go to, say, ten meters? twenty meters? That way I could have the actual AP in my little "data centre" in the cellar with all the other hardware (nas, routers, switches and so on) and wouldn't need to place (and hide) them somewhere close to the antenna

6. How does a point to point wifi setup differ from a regular setup in terms of configuration? I guess you still need some kind of SSID? Or can you actually configure routers to have a single point-to-point connection - possibly even skipping TCP/IP protocol altogether and use the Wifi as if it was a hardware link.

I'm grateful for any inputs

finalius

Q. Those should be "dedicated" point to point connections, so no regular "Access Points".
A. You still have an access point. What you are thinking of using a PtP system where you have two and only two radios for each link. If you have a single AP that connects to both your neighbor and your dad, that is called a PtM link and has AP EIRP limitations becasue it's PtM and no longer PtP.

Q1. What kind of hardware do I need? Should I take a standard cheap $40 802.11n router with a standard RP-SMA plug.
A. Get a "real" system. Ubiquiti Networks, Inc. has what you need. For your neighbor's hop, a pair of Loco M2 radios. For across town, a pair of NanoBridge M5 radios.

Q2. Apparently, this is the crucial question: which antennas should I get?
A. Many wireless systems have built in antennas. The above mentined Loco and Nanobridge have built in antennas.

Q3. The antennas have all kinds of different outputs (measured in dBi or similar). Do some of them come with an "Amplifier" that needs additional power? I find it hard to believe that a passive antenna can amplify a signal
A1. Antenna have different gains listed by dBi.
A2. Never use an extra amplifier. Seme "antennas" have the radio built in. See above for radios with built in antennas.
A3. Passive reflectors would need to be the size of an outdoor advertising billboard,

Q4. Could I mount those antennas indoors, e.g. behind a window, or would the glass already be too much of an obstacle for the connection?
A. Some glass is treated with a metallic film and would block the signal. Anything not mounted outside on a roof would have low signal levels.

Q5. How long can the antenna wire (the wire from the AP to the antenna) be at most? Is there a limit?.
A. Almost all solutions use the radio mounted right next to the antenna instead of very lossy long lengths of coax. Use CAT5 cable up to330 feet.

q6. How does a point to point wifi setup differ from a regular setup in terms of configuration? I guess you still need some kind of SSID? Or can you actually configure routers to have a single point-to-point connection - possibly even skipping TCP/IP protocol altogether and use the Wifi as if it was a hardware link.
A. All wireless setup use an AP with an SSID that a client associates to the AP's SSID. Everything is standard TCP/IP ethernet networking.

Thanks for your reply and recommendation of hardware.

I've had a look at the ubiquiti stuff before and the only thing that made me hesitate was that their hardware generally seems to come with a 10/100 LAN port. Their website claims to have "150+ MBps real throughput" which I might even be able to achieve (especially to my neighbour because there I really have ideal conditions), but what good will 150MBps wifi do if the thing only has a 100mbit lan port?

edit: what's your thought on the Powerbridge M5? According to the specs it is capable of going up to 20km. And it looks a lot nicer than a dish

http://www.wirelessforums.org/how-to...ink-67730.html

Thanks for the link to your guide, which helped me understand the technicalities behind long distance wifi better.

So, apparently Ubiquiti hardware seems to be the stuff to buy. I'm only fussing because of the 100MBit ethernet link

I think I'll start with the link to my neighbour with two locoM5 MiMo devices. They're sold by a local vendor and are even on stock at around $120 a piece. If nobody starts shouting within the next couple of hours, I'll drive over there tonight and pick them up. Let you know how it goes

I picked up the loco M2 radios at my dealer earlier. The contents of the package was minimalistic. The device, the poe injector and a power cord. No rj45 cable, no manual, not one other thing - refreshingly lean in the age of the internet.

The first connection setup was in my living room over a sheer insuperable distance of 12 meters. One device was attached to my lan, the other to my laptop. I founf the default username and pw on the carton and connected to first device using the discovery software i found on the website. First thing on the agenda was a quick firmware upgrade, then i started to set everything up.

If you have no idea about wifi, the whole setup menu is a bit technical, then again this is very dedicated hardware and this can be expected. After a few tries and errors the connection was established at max signal strength and speed.

According to the menu, i should have had 300mbit wifi speed, but the speed test (both the internal provided by the devices and netio) maxed out at 92mbit (very constant 92mbit but still only 92mbit). This is expected due to the 100 base lan connectors - sadly the thingies dobt have gbit just yet.

Ive set things up as a pure bridge for now. I will test the routing functionality later as both my neighbour and my dad will want to keep their own subnets, but from what i saw the device supports a full subnet routing and not just nat/pat of your average home router.


What followed was a lot of fun. Equipped with one device, my laptop and my cell phone, i hopped into my car, plugged it into the car's cigarette lighter plug and started driving toward my dad's office, stopping every 100 meter or so where my brother who stayed at home could see me and we tested the connection. Depending on how good the line of sight was, speeds varied between max speed and 30mbits. Eventually, i arrived at my dads office. Over 975 meters, the system clocked in at 70mbit/s and a latency of 3ms - and this is the cheap version i bought for the connection to my neighbour.

Its a very clear night tonight though. It will be intressting to see what the connection will be like when its raining, foggy or snowing.

Thanks again for the amazing recommendation - i can recommend the loco m2 to anyone who is considering setting up something like this. The only downside is the 100mbit lan port as the rest of the device would be able to handle more bandwith.

okay, the two loco M2s are now mounted to the walls at either building and the connection is set up. I get roughtly 70MBit/s of total transfer speed over 1.1km. I still have to wait for bad weather to see how that affects performance.

I've set up a ping to a fixed server down there every minute to check response times and a transfer test every 5 minutes to log speeds.

Nice post! I agree everything with you say. I know that the wireless connection is a special type of the connection in which it establish the point to point connection. The main advantage of the wireless connection is that our data pack-ate don't travel to the different bridge so our speed is increase .It has the free of the network traffic.
In the my opinion , this forum is helpful for the client who want's to know about the network.
Lots of love , thanking you .

passive gain antennas direct energy in one direction. works just like the parabolic reflector in a flashlight.

Hi. This is James and Thanks for your reply and recommendation of hardware. This is nice to be here...

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Can someone tell me what's the range of the loco M2 I need to cover 3000 ft, i have line of sight, im trying to stream video from a couple of locations and they are about 3000 ft from the house, or do ineed 2 units of the loco M2?