Hi, I am setting up "free internet" For one of my customers. And they live in an area where there aren't houses from a mile away. "The customer lives on a farm house". What will be the most suitable antenna that will pick up a decent access point from miles away, where you don't know where the wireless signal comes from.
Having worked for a WISP for a number of years, I can tell you your best bet is a directional grid antenna. What you do is log in to the radio you are going to use, do a site survey while turning the dish around slowly and watching your signal. Try both vertical and horizontal When you get to the best signal possible lock it down. There are also other considerations you need to take into account also, like what polarity is the AP you are getting the signal from, vertical or horizontal. With a grid dish you have that choice, with a Omni it is either vertical (most common) OR horizontal ( yes you can find them). With your dish, look at the way most of the bars are oriented and that is how you can tell what polarity it is. Most of the time if the widest part is left to right (more bars going up to down) that is vertical, and the opposite for horizontal. Getting the correct polarity at a distance can increase your signal 10+ dBm. I did installs to our towers up to 6 miles away with 450mW radios on the tower and 350mW on the customer side with grid dishes, up to 1 mile with a 19dBi flat panel integrated radio and clear LOS.
Horizontal polarisation is the best for maximising long range on a grid (setup at both ends) The best for cutting through long range objects and interference though is circular polarisation, however this would entail building helical antenna's which wouldn't be what you actually asked. Circular polarisation doesn't lose power when the signal reflects off objects, horizontal or vertical polarisation would since every time an object is hit the wave changes it's polarisation from horizontal to vertical and vice versa, and loses power from the flip at the same time, if there is a lot of bounces off objects in LOS, that's a lot of signal lost en route. A circularly polarised wave doesn't change phase, so there is no power to be lost on reflection in transit to the path to target. It might be hard to find high power radios from "off the shelf" parts, but there are always signal boosters which in a "quiet" area compared to urban with high AP density would benefit you more.
I went with buying the 24dbi grid antenna. When it arrives i will be installing it on a 20ft pole hopefully it works.
That should work nicely. What radio will you be using? These are both good radios, this one is lower power but more heavy duty.: http://store.wisp-router.com/EZ3plus-D Be sure to seal your connections good with rubber tape and electrical tape. This one is higher power, you will need a RP SMA to either Male or Female N connector, depending on what your dish has. http://store.wisp-router.com/NS2-US I have used these Ubiquiti radios with very few issues. The only issue I had was with bad firmware, they updated it now, where I had to TFTP 4 radios with the same firmware in a point to multi point setup I installed for a friend, they all work fine now even after another year on them. ( they have been installed and run 24/7 for over 3 years now). Either of these radios with that dish should get you close to 2 miles ( to a router) with clear LOS.
