I've been to all the stations now and upgraded the com unit, but when I go to Ranger Station Bravo, I just find 3 people, and none are the comm officer. I've tried leaving and coming back several times, but still no comm officer.
Anyone else have this problem, or have any suggestions? I'm playing the PC version of Fallout 3.
According to the Official Game Guide, the one you are to find at Station Charlie is Ranger Stepinac. I completed the code quest (Return to Sender) but did it a little differently than you. I visited Station Charlie early in the game before I had gotten the code quest. The rangers where just hanging out and didn't offer much so I didn't pay much attention to them. I then went to Novac and talked to Ranger Andy who gave me the free quest to check on Station Charlie. When you go back to Station Charlie, all the rangers are dead. Later in the game I got the code quest and there is no living comm officer at Charlie. However, you will still complete Return to Sender by reporting the loss of the station to Sgt. Reyes.
So, maybe try that. Talk to Andy at Novac, check on Station Charlie to see if they are dead, tell this to Andy, and then return to Reyes to complete Return to Sender.
Edit: My mistake, I thought you were asking about Station Charlie. Ignore that man behind the curtain.