Frequency: MHz
Lambda λ: mm
Length L1: mm
Length L2: mm
Length B: mm
Length H: mm
Wire Diameter: mm
Wire Length: mm
Distance D*: mm
Distance A*: mm

D* = Distance BETWEEN reflector and antenna.
A* = CC distance between two antennas if dual bi-quad.

A bigger version of the drawing.

Calculator originally from but
slightly modified to also work for dual biquad.