What is the percentage of optical coverage of a screen shall be calculation ?

D is the average diameter of the screen (diameter under the screen plus 2 d in mm);
d is the nominal wire diameter in mm (used for the screen);
S is the lay length of wires in the screen in mm;
m1 is the number of bunched wires in one direction (number of small spools);
m2 is the number of bunched wires in opposite direction (number of small spools);
n1, n2 are the number of wires used for each bunch

MIL-DTL-24643C

The coverage shall be as determined by the following formula: Percent coverage = 100 (2F-F2)

Where: F = NPd/Sin (a)
Tan (a) = 2 × 3.14159 (D+2d)P/C
a = acute angle of braid with axis of cable
d = diameter (inch) of individual braid wires
D = diameter (inch) of cable under braid
N = number of wires per carrier
C = number of carriers
P = picks per inch of cable length