[Loot] What is best map to seek one COFDM transmitter fast?

I have trouble advancing to Lightkeeper quests because I'm stuck at Network Provider Part 1. So far I've found two COFDMs at Reserve bunker RB-PKPTS room, but I am getting frustrated after one and a half keys of grinding that room. I have also tried unlocked loose loot locations and radar dome building but no luck so far. What other locations or maps are good for finding COFDM?