Ronja 10M Metropolis and Tetrapolis Technical Details Decision

Determine the distance between endpoints of the link. Determine necessary lens diameter from the distance. See the graphs to accomplish this task. If you want to use different lenses for receiver and transmitter, the effective lens diameter is geometrical average (square root of product) from the two original lens diameters. Some reduction in range will occur if the focal spot size of the available lens (loupe) (determined by focusing a defocused laser pointer or any other point source through the lens on a white wall) is bigger than 3mm for the transmitter or bigger than 5mm for the receiver.
Consider the fact that mounting in a position where the beam will intersect a layer of heated air above a roof or on a side of a wall may reduce the performance to shorter distance on hot sunny days.

Choose a suitable console:

Console	Requirement
Wall perpendicular	drilling eight holes into the masonry
Wall parallel	drilling four holes into the masonry
Wall corner	Corner on the building
Chimney	Suitably small chimney
Railing	Stable iron railing (wooden would creep)
Mast	Stable vertical steel mast

Determine the length of the cables. Actually, distance between optical heads and the PC, measured along intended cable path. If it is bigger than 30m, usage of high-frequency coaxial cable (that is used for radio or TV antenna) is recommended.