Signal Alfa Lima

When the ham radio's switch at broadcast tower KB5 is flipped, the Alfa Lima signal becomes active. If one goes east-southeast of the tower and drops off a small cliff, they will land on top of a sewer grate leading to a drainage chamber. Upon entering, there will be an Average locked door leading to the radio. Judging by the Morse code translation, the message is asking if anyone is nearby.

Morse code
The station transmits:

Overall it says: "Calling anyone, this is Alfa Lima, over." "Over" means "I am awaiting reply."

Gallery
Радиосигнал «Альфа Лима» Радіосигнал «Альфа Ліма»