In order to augment low level warning, twelve type 3101 sqns (if I remember correctly) were purchased from USSR after 1971 war. (MOFs were not effective during night/bad weather). Each sqn consisted of two radars ie P-12 and P-15. P-12 radar was medium looking while P-15 was low looking. The sqns were primarily meant as early warning with very limited control facilities. The sqn had two Fighter controllers including the OC and one AE(L) officer. Later on, P-12 and P-15 radars were replaced with newer versions of P-18 and P-19 radars. Some of these were also used at BADC`s as local airfield surveillance radars.