To condense the above into what you're trying to achieve:
1. use the sentech zonelocator, at http://66.18.65.122/zonelocator/welcome.htm to find your site/address
2. once you've got the location, open the abovementioned rational distance calculator in a separate browser- he DOES have accurate tower data
3. get the 2nd browser ready to take input (in whatever city you happen to be)
4. use ALT-TAB (presuming Windows usage here..) to flip back to your zonelocator page and hover the mouse on The Spot(tm), ie your site
5. look in the bottom LHS of the zonelocator and it'll show you the GPS data for your site
6. without moving the mouse, flip back and forth between the zoneloc page and the rational page and input the numbers
7. get the rational site to give you its numbers- which'll be distance (mildly interesting to you at this stage) and bearing
8a. know how to convert that bearing number into something useful outside/away from the browser- knowing north helps here
8b ..cheat by using a GPS- 's what I do *G*
On a separate note, I wouldn't count TOO much on a cantenna "dramatically" improving your signal- but it's certainly worth a try! But you should be able to get the thing aimed in the right direction. Also, as mentioned above, the ProAsm dialer is a GREAT tool to fine tune your signal, the method here is to go to the [MySignal] tab and click on the (yellow) phone icon- this'll switch on its live monitoring mode which'll enable you to do the search thing. You'll know you have it in monitoring mode by the icon going red and getting a fluctuating (level) yellow bar up the middle, and numbers jumping up and down as you hunt around for the best position. Tip- do BOTH axes- I'd recommend doing the horizontal plane (technically known as azimuth) until you get max numbers FIRST, THEN check out the vertical (elevation) plane to get the sweet spot. Then make DAMN sure you lock that position down in some way ..duct tape may help at this point! *efg*
And if the cantenna gives you the improvement you're looking for, you CAN relax once your signal goes over 21%- I find that's usually the point that the BER number hits 71%- the highest it ever seems to go. If it doesn't do like you're hoping- well, sometimes you luck out and find someone in this bunch of semi-literate malcontents that actually posts something helpful!