I clicked around the office before starting my mission, but did not land on the radio.

But now I know!
And I should have told you that I am playing SH 1.5 with THEBERBSTERS Mega Mod. As for whether or not that works with the 'H' key, I don't know. I just logged out, but will try again this evening.
Yes, I am in a Gato boat, and probably was not when playing the quick missions, so I will also look at Gato's Sonar Bearing fix.
Lastly, the part about the lock not working due to visibility makes sense, but even there, good advice to come up a few feet to get better clearance for my periscope in heavy seas.
Thanks you guys! Subsim seems like a great community!