To simulate the battlefield repair of SAM/EWR, I wrote this script which features an Unlimited SAM/EWR sites respawn with a user-defined delay.
It also includes a random location respawn feature for SAM
-- Setup Delay time (unit is second)
local SAM_Respawn_Delay = 1200
local EWR_Respawn_Delay = 600
-- If a SAM site is covered by a trigger zone (* and they have SAME group name), then the SAM will respawn at a random location inside the zone if being destroyed. Otherwise, at default location.
-- Currently the AWACS part does not work properly, so not enabled.