camlobe - I recently departed a non-towered airfield, but mandatory broadcast nonetheless. Selected the common frequency, advised taxying, heard, and saw, no traffic, so adv. line up and hold, completed checks, adv. rolling, adv. leaving the area. Very quiet, I thought. Upon selecting the next frequency .... oops ! done the whole thing on the wrong frequency. That's with 20,000 hours plus ( of course I usually had a co-pilot to handle the radio ! ) We all make mistakes, the trick is to learn from them.