Signal Alfa Lima

When you flip the ham radio's switch at broadcast tower KB5, the Alfa Lima signal becomes active. If you go east-southeast of the tower and drop off a small cliff, you will land practically on top of a sewer grate to a drainage chamber. Once you enter, you will find an average locked door leading to the radio.

Morse code
The station transmits:

So overall it says: "Calling anyone this is Alfa Lima over". Basically, "over" is actually saying "I am awaiting reply".