Narrative:

I'm a certificated private pilot; sel; but I haven't flown much in the last 7 years. I've been flying recently and am working with an instructor to regain my proficiency. Today I had a number of problems with my radio communications that may have affected others using the frequencies in question.in leaving oak to the north we terminated radar services above san pablo bay and proceeded to perform some basic maneuvers. When we were granted the frequency change from nct departure I simply turned the volume on communication 1 down so that it wouldn't interfere with my instructor's directions.after we were done with our maneuvers we proceeded to dvo for some uncontrolled airport practice. As we were approaching the airport rather than set the frequency on communication 1; I decided to leave it alone (to retain the nct and oakland tower frequencies) and instead set the dvo CTAF into my communication 2 radio. Unfortunately I made the mistake of only enabling the receive function on the audio panel for communication 2 and failed to rotate the transmit knob to communication 2. The result of this mistake was that for the next 30 minutes while I was performing touch and goes at dvo all of my pattern position reports were transmitted on the communication 1 radio which was still set to nct departure. There was not much traffic at dvo so it wasn't clear to me that those in the pattern could not hear my transmissions and because I had the volume on communication 1 turned down I could not hear nct reporting my mistake to me.upon departing dvo to return to oakland for some reason I tuned communication 2 to nct approach. Once I established contact there they informed me of my mistake but were very gracious when I apologized for what I'd done. Unfortunately; this got me worried about the radio situation and I decided to try and correct it while traveling south towards oakland. In correcting it I tuned communication 1 back to nct approach and made sure the audio panel was setup correctly for communication 1 and that communication 2 was turned off. After a few minutes of not hearing any more traffic on the frequency I began to wonder if I'd messed something up and this is when I realized that I'd failed to turn the volume on communication 1 back up after I'd switched back to it. When I turned the volume up the first transmission I heard was nct approach very clearly calling my aircraft and instructing me to contact oakland tower. It seemed clear to me that I'd already missed at least one call from nct before I finally picked them up.at this point I acknowledged the frequency change instruction; contacted oakland tower and proceeded to land without any further incidents.it's clear to me that I did not fully understand how to operate the audio panel in the cessna 172 sp that I was flying and that switching to the second communication radio led me to cause problems for other aircraft and controllers on the frequency. Unfortunately my instructor didn't catch the error either but he clarified the audio panel function for me once we learned of my mistake.

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Original NASA ASRS Text

Title: A private pilot and his instructor failed to recognize inappropriate com radio settings during a training flight. As a result they transmitted numerous transmissions to unintended recipients; disrupting air traffic control and operating touch and go landings at an uncontrolled airport without position and intention reports to other traffic.

Narrative: I'm a certificated private pilot; SEL; but I haven't flown much in the last 7 years. I've been flying recently and am working with an instructor to regain my proficiency. Today I had a number of problems with my radio communications that may have affected others using the frequencies in question.In leaving OAK to the north we terminated radar services above San Pablo bay and proceeded to perform some basic maneuvers. When we were granted the frequency change from NCT Departure I simply turned the volume on COM 1 down so that it wouldn't interfere with my instructor's directions.After we were done with our maneuvers we proceeded to DVO for some uncontrolled airport practice. As we were approaching the airport rather than set the frequency on COM 1; I decided to leave it alone (to retain the NCT and Oakland Tower frequencies) and instead set the DVO CTAF into my COM 2 radio. Unfortunately I made the mistake of only enabling the receive function on the audio panel for COM 2 and failed to rotate the transmit knob to COM 2. The result of this mistake was that for the next 30 minutes while I was performing touch and goes at DVO all of my pattern position reports were transmitted on the COM 1 radio which was still set to NCT Departure. There was not much traffic at DVO so it wasn't clear to me that those in the pattern could not hear my transmissions and because I had the volume on COM 1 turned down I could not hear NCT reporting my mistake to me.Upon departing DVO to return to Oakland for some reason I tuned COM 2 to NCT Approach. Once I established contact there they informed me of my mistake but were very gracious when I apologized for what I'd done. Unfortunately; this got me worried about the radio situation and I decided to try and correct it while traveling south towards Oakland. In correcting it I tuned COM 1 back to NCT Approach and made sure the audio panel was setup correctly for COM 1 and that COM 2 was turned off. After a few minutes of not hearing any more traffic on the frequency I began to wonder if I'd messed something up and this is when I realized that I'd failed to turn the volume on COM 1 back up after I'd switched back to it. When I turned the volume up the first transmission I heard was NCT Approach very clearly calling my aircraft and instructing me to contact Oakland Tower. It seemed clear to me that I'd already missed at least one call from NCT before I finally picked them up.At this point I acknowledged the frequency change instruction; contacted Oakland Tower and proceeded to land without any further incidents.It's clear to me that I did not fully understand how to operate the audio panel in the Cessna 172 SP that I was flying and that switching to the second COM radio led me to cause problems for other aircraft and controllers on the frequency. Unfortunately my instructor didn't catch the error either but he clarified the audio panel function for me once we learned of my mistake.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.