Down to basics, PLEASE, on wifi directional antenna connection

unlistedmoniker

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Jan 30, 2013
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I've read over a hundred articles and threads on this subject, and everybody seems to continually jump past the basics of a directional wifi antenna connection to public wifi as if they were a given. so - 1. I have a directional antenna. 2. I have a public wifi hotspot about 70 yards away. I do not have access to their repeater 3. I need to know how to get that wifi signal to my computer/streaming devices. Everybody glosses over the connections between the antenna and the pc. So - 1. What does the antenna get connected to? it has an rp-sma cable attached. 2. is some sort of repeater amplifier required? 3. can it be directly connected to the router instead if the signal is strong enough? (assuming the router has the rp-sma antenna connection available) These steps seem to be omitted from every thread and article I've read and they are precisely the questions I've been searching for the answers to. Thanks for the help.
 
Solution
At 70 yards, follow bill001g's advice and just get an outdoor directional client-bridge. 70 yards is child's play, and just about any commercial device will work.

If you were talking like a mile or 10 miles, then you might want to put together some sort of custom job (though there are dedicated directional bridges you can get for those ranges too). You plug the antenna cable directly into the RP-SMA connector on a wireless router or bridge (where the little whip antennas on the router screw into). You do NOT use an amplifier. The broadcast signal strength in these open bands is limited by FCC regulations (typically to 1 Watt), and wifi equipment and routers are designed not to exceed that. If you add an amplifier, you will...


Your directional antenna's jumper cable would need to connect to a wifi adapter card or USB adapter, like an Alfa AWUS036NW. (Someone wrote that you'd plug it into a router, but that's the case only if you have a wifi-as-WAN router specifically configured for this usage, like the Pepwave Surf SOHO router). I don't know specifically which connector your jumper cable has, but indoor routers and adapters usually have RP-SMA female ports, which would make with an RP-SMA male connector threaded on to them. The adapter is what does all the thinking, and would connect to your PC via USB cable or via a PCI-e port on a motherboard (if it's that kind of desktop adapter).

70 yards isn't very far if you have line of sight, but whether this would work or not depends on the specific equipment used. You can calculate a link budget by adding the antenna's gain, the adapter's receive power, and then subtracting the free space loss and any loss from obstructions breaking up the line of sight.

The benefit of using the directional antenna and adapter is that 1. you already have the antenna (apparently), and 2. you can upgrade the adapter as wifi standards evolve without being locked in to a particular vendor for the entire assembly. I'm not sure the other commentators understand that you don't have right of access to the wifi hotspot, which makes the discussion about wireless bridges moot since you can't create a point to point link between the two sites. (Only a few Ubiquiti NanoStation models can be used as a router, and you might actually like your current router, and besides, their antenna gain is puny compared to what you can get with a parabolic grid antenna.) In any case and whatever the specific gear used, you'd want to maximize your receiver gain with a high-gain antenna. (And if someone tells you a solution is "trivial" to configure, they might not be helping you answer the basics, which is why you came here, and are also lowballing the total cost of the solution.)

A "repeater" is the same as a range extender. You don't need that in your scenario, and there are few scenarios where using one is actually beneficial. An amplifier is the same as a "signal booster." It would generally increase transmit gain by amplifying the wifi signal coming from a router's radio chain. Since you're on the receiving end and not the transmitting end, you don't need one, nor would one generally be necessary except in certain industrial or enterprise deployments where attention to radiated power (EIRP) limits is given. But what you could do to increase received signal strength is upgrade the antenna for higher dBi gain, if it's an issue.
 
Use of actual antennas and microwave cables is the old way to do this. When you look at the costs of the antenna and especially quality coax so you do not get too much signal loss it is just not your best option any more.

The simple method is to buy a outdoor directional client-bridge from a company like ubiquiti or engenius. You can get a device in the $50 range. Which exact unit depends on if the hotspot is using 2.4g or 5g and what encoding. It may be worth paying more for 802.11ac if the hotspot can run that.

These devices are trivial to hook to a pc. They generally have a power injector to power the bridge that is inside the antenna enclosure. They use common etheret cable both to hook to your PC and to hook the the bridge. The only thing that might get complex is if you want run multiple devices off this connection. Since you have no access to the hotspot and most do not support WDS it gets tricky. The good news is the ubiquiti devices can run as a router and allow you to share the connection with multiple devices. You would need a small switch in your house in addition to the outdoor bridge.
 
At 70 yards, follow bill001g's advice and just get an outdoor directional client-bridge. 70 yards is child's play, and just about any commercial device will work.

If you were talking like a mile or 10 miles, then you might want to put together some sort of custom job (though there are dedicated directional bridges you can get for those ranges too). You plug the antenna cable directly into the RP-SMA connector on a wireless router or bridge (where the little whip antennas on the router screw into). You do NOT use an amplifier. The broadcast signal strength in these open bands is limited by FCC regulations (typically to 1 Watt), and wifi equipment and routers are designed not to exceed that. If you add an amplifier, you will probably exceed it, and any complaint to the FCC could result in heavy fines.

You can however use a signal booster. In fact that might be necessary if your antenna cable is long. The signal captured by the antenna degrades the further it needs to travel down a cable. A booster sits right next to the antenna (where the signal is still pristine) and amplifies it in the cable (not the radio broadcast signal, so no problems with the FCC). That way you can use a long cable which reaches from your roof to your ground floor. (The other option is to use a thicker cable, which can get expensive and difficult to install).
 
Solution