The rear sight s drop arm has a range scale engraved with settings from 1 to 10 ( corresponding to firing ranges from 100 to 1, 000 m, graduated every 100 m ) and a fixed setting S that is the equivalent to setting 4 on the range scale.
22.
Before the First World War it was fitted with oscillating ( reciprocating ) sights, using the older No 5 sighting telescope ( x12 magnification ) on either Sight Oscillating BL 60 pr Mk I or II, which included a sight clinometer and range scale as well as a deflection drum for the telescope.
23.
This was accomplished by bringing the "'gun arm "'of the plotting board over this point, and reading the "'range "'from the directing point to the target off the range scale on the edge of that arm and the "'azimuth "'from the directing point to the target off of azimuth circle of the "'gun arm center " '.
24.
First of all, WW2 radars didn't have the same kind of displays that modern radars have, with dots representing targets-- what they had was an oscilloscope with a range scale, which showed the outgoing pulse at zero range, and return pulses at their respective ranges ( calculated using a basic pulse-delay system and displayed in simple analog format ), plus mechanical indicators for bearing and elevation.
