How to Set Up a Microwave Internet Link Over Distance
Jul 11, 2013 5:00 AM PT
Around this time of year some buddies and I usually pack up a bunch of our brick-like ham radios, a few unwieldy 30-foot masts, a helium balloon antenna and some pop-up shade shelters and lug it all over to a local mountaintop near our suburban Los Angeles homes.
We traipse up the baked hillside with this gear each year to perform a nonstop radio experiment that lasts over a weekend. Its purpose? To see how many other fanatical radio-heads we can contact around the world, bouncing signals off the ionosphere and the like -- all off the grid using batteries instead.
One technology we've lacked -- until now -- has been useful Internet up on that scorching hill: wireless carrier signals have been spotty.
This year, however, we've been successfully experimenting with a point-to-point Ubiquiti Networks bridge product. The founders of Ubiquiti were behind early Motorola wireless Internet products, and Ubiquiti now makes an US$80 antenna that the company reckons will bridge a WiFi signal 30 kilometers.
We've been sending the signal about half a mile no problem.
This is a project that would have cost thousands of dollars to do just a few years ago, but it can now be achieved for less than $200.
Here's how to approach the project if you have a similar application. Like-minded uses could include sharing an Internet service between home and outbuilding or even a home and workspace over miles.
The secret is to get a line-of-sight signal.
Step 1: Obtain the parts
You will need two microwave antennas; some long Ethernet cables; a couple of photographic tripods; a laptop; an old WiFi Router; and power.
I recommend the Ubiquiti AirGridM 5 GHz microwave broadband antenna, which is what we used. The radio is integrated in the antenna feed.
Step 2: Survey the application by eyeballing the path that the signal will take
The key thing to remember about 5 GHz WiFi is that it's a minuscule wave and is line-of-sight at distances. This kit won't work if you have a ridgeline in the way at short distances, or even tree limbs at long distances. We used a friend's home to supply the Internet because it is in sight of our mountaintop.
Step 3: Set up the hardwareMount the two antennas onto photographic tripods using the antenna-included hardware.
Then align the two antennas at their prospective locations by pointing the antennas at each other. The shorter the distance, the less accurate you need to be.
Tip: For a permanent install, use the included hardware with optionally available masts.
Step 4: Set up the access point network (the side with Internet)
Connect the included Power Over Ethernet injector to a power source near the incoming Internet router. Internet can be supplied by a normal domestic modem or router.
Then connect an Ethernet cable from the POE injector to the Ubiquiti access point antenna, and from the POE injector's LAN port to a laptop with another one of the Ethernet cables.
Assign a static IP address to the laptop. Use the address provided by the antenna manufacturer -- it will be in the documentation. Then save the settings, open a browser and navigate to the IP address provided. The access point's dashboard will open.
Enter the User ID and Password -- Ubiquiti's is always "ubnt." Then open the Wireless tab, set the Wireless Mode to Access Point WDS and create a unique SSID.
Set the security to a preferred mode, like WPA2-AES or similar. Use PSK for authentication. Enter a key.
Then choose Bridge from the Network tab and enter the network settings provided in the antenna's documentation.
Tip: Ubiquiti recommends some point-to-point mode changes for long distances, like one called No Ack.
Access these settings in the first tab on the dashboard. The documentation will advise what to use. Don't worry about this if your link is less than 17 km.
Step 5: Set up the station network (the side at the remote location)
Follow the same steps that you performed with the access point, except that the wireless mode should be set to Station WDS, not Access Point WDS. Then lock to the access point's SSID that you set up earlier.
Step 6: Deploy the access pointSwitch off the incoming Internet modem or router and POE. Then unplug the laptop cable and plug that cable into the Internet supplying router. Turn everything back on again.
Step 7: Deploy the stationFollow the same deployment process as with the access point except plug the configuring laptop cable into a now nonstatic IP-addressed laptop or a configured 2.4 GHz household WiFi router.
Tip: Use an automotive 12-volt battery and inverter to provide power at the remote site if necessary.
Step 8: Test
Internet will be available on the laptop or WiFi network at the remote location.
Tip: Run the channel selector utility under the Tools menu to find a clean channel if results are poor. Look for swaths of color representing pollution on the waterfall graphic.
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