Signal Sierra Romeo

Broadcast tower KT8 is located directly north of Little Lamplight and northeast of Vault 87. Upon activation of the tower you will receive the Radio Signal Sierra Romeo in Morse code. Down a cliff northeast of the tower is a drainage chamber which can be easily seen from your local map. This is one of nine drainage chambers broadcasting a Morse code signal.

Drainage chamber
Inside this tiny dungeon you will find some interesting things, including two pre-War books and a motorcycle handbrake and motorcycle gas tank, Pork n' Beans and Sugar Bombs. There are two terminals, one broken and the other with some mixed script with the error of an "invalid decry.key" when activated. Behind you on the third desk lies the encryption key. Use it on the encrypted terminal to open the trap door on the floor to your right.

Downstairs you will find your Ham radio signal source and two Dead Chinese remnant spies. In this chamber there's also a mini nuke, a Chinese Army: Special Ops Training Manual, a Chinese Commando Hat, two bottles of purified water under the desk, and various other objects.

Interesting enough this place can be owned and items will not disappear. A glitch which lets you close the chamber again can be performed by backing up until you can barely activate the electric switch. The moment after you activate it backup and you will walk through the trap door. It will only be owned if you close it.

Morse code
The station transmits:

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