Note: This calculator is still VERY beta-version... I re-wrote many of the formulas from scratch, therefore your results may not be correct. See below...
Azimuth values are NOT corrected for magnetic deviation (yet...)
v0.9.1 April 10, 2003
Testing has shown that Elevation/Azimuth is accurate to several decimal places, but the skew angles this calculator generates vary by 1-5° from the values quoted by ExpressVu's install guide. I believe that ExpressVu calculates the skew by calculating the polarization tilt at 86.5° W, whereas my formula calculates the look angle to each satellite, then calculates the angle between the two. I think some trial and error is needed to see which calculation provides the best signal on both satellites.
At my location, my calculator gives me an angle 2.3° different than the angle provided by Bell. Using their skew angle, I get signal strengths of 87% on 91° and 67% on 82°, peaked using 91°. Using the angle provided by my calculator, I get signal strengths of 87% on 91° and 73% on 82°, peaked using 91°. Because I peaked to 91° it's signal was always at it's highest, however, a 6% increase on 82° is signifcant, and could be helpful in some situations. It would appear that this calculator works better, however your results may differ.
For comparison, try this: http://www.satsig.net/ssazelm.htm
The results generated there agree with Bell's install guide. (For skew angle, enter the midway point between 2 satellites for "Satellite Longitude" i.e. 86.5° for ExpressVu, resulting "Polarization Tilt" = skew angle)
v0.9.0 March 28, 2003: Original Release
v0.9.1 April 10, 2003: Fixed Skew angle for locations that look west to the satellites, i.e. Ottawa... for Dish500 it would read 61.1°, really should read 118.9° (just a simple operator change, but thanks to Steven S. for pointing it out...)