|The following is based on Van Buren and is not canon.|
Use the Big Radio to Signal ARGOS was going to be a quest in Van Buren, the canceled Fallout 3 by Black Isle Studios. It is located at Denver.
If you want to call ARGOS to your location (for example, if you want a quick trip back to ODYSSEUS), you can use the repaired radio tower to broadcast a call to him.
This might be a good way to grab Daniel even if he's unwilling.