Fallout 3 radio stations

Characteristics
Radio stations can be accessed with the Pip-Boy 3000 in the Capital Wasteland. Other radio signals can be found that are related to quests. While the sounds of the radio resonate with the local environment, it does not affect the Sneak skill.

Stations

 * Agatha's Station
 * Enclave Radio
 * Galaxy News Radio
 * People's Republic of America Radio
 * Pitt broadcast
 * Tenpenny Tower radio
 * Vault 101 PA System

Quest related temporary signals

 * Ranger emergency frequency
 * Vault 101 distress signal
 * Wernher's distress signal
 * Outcast distress signal
 * Recon craft Theta signal

Temporary signals
Finding ham radios, one can turn them on to hear the following:

Morse code signals
The Morse code signals can be decoded to decipher a message, and they must be turned on at the towers they are being broadcast from. These radio signals will become clearer the nearer one gets to the ham radio, not the tower that broadcasts the signal.