Joel, Depending on the angles involved to the tower, and the tower shape you may be able to just bounce the signal off the tower itself. Wouldn't take much to try it. 21 dB over isotropic is aiming quite a bit of signal in the desired direction. Same concentrating effect is seen on the receive side. If you're driving, say, 100mW into the antenna this would give about 10 Watts ERP, which is a robust signal at 2.4 Ghz. 73, Bob KA0Q Joel R. Helgeson wrote: > I have a design question for a project that I am working on for my > work. I would like to run it past my friends here in the TCWUG to see > if you can see any flaws in my thinking or my design. Any feedback will > be valuable. > > > I am currently designing a Wireless Bridge between Fridley & Brooklyn > Park. The total distance of the bridge is 4.45 miles. We cannot obtain > direct line of site between the two sites without building a 200? tall > tower at the site in BP, but both have a clear line of sight to a water > tower in BP. The distance from Fridley to the BP Water Tower is 3.88 > miles; the distance from the BP site to the Water Tower is .941 miles. > I will be using 21dbi Parabolic Dish antennas at each site. > > > > The design I am proposing is to use a passive antenna array atop the > water tower, just take two 21dbi Parabolic Dish antennas and connect > them back to back using a lightning arrestor, having one dish point to > Fridley and the other to the BP office. I figure I could pull this off > because of the short distances involved, and the customer doesn?t want > to pay monthly rental fees to put a radio atop the tower (paying for > electricity & all), much less suffer the throughput loss (from 11mbps to > 5.5mbps) that one does by using a radio relay. > > > > I think this could work, but is there something I?m missing? Has anyone > else done this before? I?d hate to recommend something that won?t work. > > > > Thank you for your help in advance, > > > > Joel R. Helgeson > > Director of Networking & Security Services > > SymetriQ Corporation, www.symetriq.com > > 8500 Normandale Lake Boulevard, Suite 1670 > > Bloomington, Minnesota 55437-3813 > > Office: (952) 921-8869 > > Cell: (651) 270-7521 > > > > > > "An investment in knowledge pays the best dividends." - Benjamin Franklin > > >