Narrative:

Both communication #1 and communication #2 had previously been pulled from aircraft for service (intermittent reception). In place of these radios, I chose to use an A-20 handheld. I used a 6 inch length piece of 50 ohm coax cable and 50 ohm barrel to connect the A-20's antenna jack to the vacated bnc jack in the rg's avionics stack. I also connected a headset adaptor and push-to-talk switch to the A-20. From stockton to pao, I made radio checks along the course of flight. Other than some reports from luk tower and stockton approach that the transmission was a little weak, they acknowledged that the reception was understandable. For example, I contacted livermore tower at about 7 mi out. I had also been on flight following previous to pao. I assumed that all was ok. After receiving pao ATIS near livermore, I switched to pao tower frequency at approximately 10 mi out and did receive it loud and clear. However, when I got to leslie salts (approximately 6 mi from pao), the A-20's reception became broken up. I radioed pao tower several times and received no response. A nearby aircraft received my transmission and reported to pao tower that an aircraft had attempted to contact them, but that the transmission was broken up and mostly unreadable. At this point, I chose to rock my wings and turn on the landing light. I forgot to squawk 7600, as I have never practiced using the squawk code before. I then chose to change the antenna on the A-20 from the outside unit to the stick antenna and also unplug the headset adapter cord from the radio, freezing the radio from all external influences. Suddenly, all receptions and xmissions were clear, but the following major obstacle remained: the A-20's up/down frequency scan buttons are always active! Before the flight, I had attached the headset adapter cord to carrying strap loop on the side of the radio to keep the cord from being pulled out during flight. Upon entering the pattern, I picked up the A-20 to transmit my intentions. While picking up the radio, one of the phone receptacles that was attached to the cord hit the 'upscan' button on the A-20 and changed frequency from '118.60' to '118.65.' this error occurred twice -- once on downwind and once on base -- leaving me in a panic. I was already feeling a lot of stress from the radio failure that had occurred over leslie salts. Each time I noted the frequency had changed on the A-20 I lost situational control of the aircraft. For example, I lost altitude and did not put the gear down until turning base -- I usually have the gear down before entering the pattern! One of the factors that affected my performance in the aircraft was lack of a good night's sleep. I had stayed overnight in stockton because of poor visibility conditions along the route back to pao. I did not sleep well this night and felt groggy the morning of the flight. I also had doubts about the radio hook-up using the A-20, for I believe that the causes of previous radio reception problems in the aircraft's communication system are numerous and may include possible antenna-related issues. I chose to use the aircraft's antenna system despite having doubts about its performance. Having this hunch, I did call pao to warn them that I was heading their way and that I might encounter radio problems in the pattern. Unfortunately, I got an answering machine. I chose not to leave a message as I figured that I would get there before the message played. In the future, I'll take my hunches more seriously!

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Original NASA ASRS Text

Title: LOW TIME PLT JURY-RIGGED RADIOS WHICH EVENTUALLY BECAME UNUSABLE BECAUSE OF FAULTY ANTENNA. ENTERED CTLED ARPT WITHOUT RADIOS.

Narrative: BOTH COM #1 AND COM #2 HAD PREVIOUSLY BEEN PULLED FROM ACFT FOR SVC (INTERMITTENT RECEPTION). IN PLACE OF THESE RADIOS, I CHOSE TO USE AN A-20 HANDHELD. I USED A 6 INCH LENGTH PIECE OF 50 OHM COAX CABLE AND 50 OHM BARREL TO CONNECT THE A-20'S ANTENNA JACK TO THE VACATED BNC JACK IN THE RG'S AVIONICS STACK. I ALSO CONNECTED A HEADSET ADAPTOR AND PUSH-TO-TALK SWITCH TO THE A-20. FROM STOCKTON TO PAO, I MADE RADIO CHKS ALONG THE COURSE OF FLT. OTHER THAN SOME RPTS FROM LUK TWR AND STOCKTON APCH THAT THE XMISSION WAS A LITTLE WEAK, THEY ACKNOWLEDGED THAT THE RECEPTION WAS UNDERSTANDABLE. FOR EXAMPLE, I CONTACTED LIVERMORE TWR AT ABOUT 7 MI OUT. I HAD ALSO BEEN ON FLT FOLLOWING PREVIOUS TO PAO. I ASSUMED THAT ALL WAS OK. AFTER RECEIVING PAO ATIS NEAR LIVERMORE, I SWITCHED TO PAO TWR FREQ AT APPROX 10 MI OUT AND DID RECEIVE IT LOUD AND CLR. HOWEVER, WHEN I GOT TO LESLIE SALTS (APPROX 6 MI FROM PAO), THE A-20'S RECEPTION BECAME BROKEN UP. I RADIOED PAO TWR SEVERAL TIMES AND RECEIVED NO RESPONSE. A NEARBY ACFT RECEIVED MY XMISSION AND RPTED TO PAO TWR THAT AN ACFT HAD ATTEMPTED TO CONTACT THEM, BUT THAT THE XMISSION WAS BROKEN UP AND MOSTLY UNREADABLE. AT THIS POINT, I CHOSE TO ROCK MY WINGS AND TURN ON THE LNDG LIGHT. I FORGOT TO SQUAWK 7600, AS I HAVE NEVER PRACTICED USING THE SQUAWK CODE BEFORE. I THEN CHOSE TO CHANGE THE ANTENNA ON THE A-20 FROM THE OUTSIDE UNIT TO THE STICK ANTENNA AND ALSO UNPLUG THE HEADSET ADAPTER CORD FROM THE RADIO, FREEZING THE RADIO FROM ALL EXTERNAL INFLUENCES. SUDDENLY, ALL RECEPTIONS AND XMISSIONS WERE CLR, BUT THE FOLLOWING MAJOR OBSTACLE REMAINED: THE A-20'S UP/DOWN FREQ SCAN BUTTONS ARE ALWAYS ACTIVE! BEFORE THE FLT, I HAD ATTACHED THE HEADSET ADAPTER CORD TO CARRYING STRAP LOOP ON THE SIDE OF THE RADIO TO KEEP THE CORD FROM BEING PULLED OUT DURING FLT. UPON ENTERING THE PATTERN, I PICKED UP THE A-20 TO XMIT MY INTENTIONS. WHILE PICKING UP THE RADIO, ONE OF THE PHONE RECEPTACLES THAT WAS ATTACHED TO THE CORD HIT THE 'UPSCAN' BUTTON ON THE A-20 AND CHANGED FREQ FROM '118.60' TO '118.65.' THIS ERROR OCCURRED TWICE -- ONCE ON DOWNWIND AND ONCE ON BASE -- LEAVING ME IN A PANIC. I WAS ALREADY FEELING A LOT OF STRESS FROM THE RADIO FAILURE THAT HAD OCCURRED OVER LESLIE SALTS. EACH TIME I NOTED THE FREQ HAD CHANGED ON THE A-20 I LOST SITUATIONAL CTL OF THE ACFT. FOR EXAMPLE, I LOST ALT AND DID NOT PUT THE GEAR DOWN UNTIL TURNING BASE -- I USUALLY HAVE THE GEAR DOWN BEFORE ENTERING THE PATTERN! ONE OF THE FACTORS THAT AFFECTED MY PERFORMANCE IN THE ACFT WAS LACK OF A GOOD NIGHT'S SLEEP. I HAD STAYED OVERNIGHT IN STOCKTON BECAUSE OF POOR VISIBILITY CONDITIONS ALONG THE RTE BACK TO PAO. I DID NOT SLEEP WELL THIS NIGHT AND FELT GROGGY THE MORNING OF THE FLT. I ALSO HAD DOUBTS ABOUT THE RADIO HOOK-UP USING THE A-20, FOR I BELIEVE THAT THE CAUSES OF PREVIOUS RADIO RECEPTION PROBS IN THE ACFT'S COM SYS ARE NUMEROUS AND MAY INCLUDE POSSIBLE ANTENNA-RELATED ISSUES. I CHOSE TO USE THE ACFT'S ANTENNA SYS DESPITE HAVING DOUBTS ABOUT ITS PERFORMANCE. HAVING THIS HUNCH, I DID CALL PAO TO WARN THEM THAT I WAS HEADING THEIR WAY AND THAT I MIGHT ENCOUNTER RADIO PROBS IN THE PATTERN. UNFORTUNATELY, I GOT AN ANSWERING MACHINE. I CHOSE NOT TO LEAVE A MESSAGE AS I FIGURED THAT I WOULD GET THERE BEFORE THE MESSAGE PLAYED. IN THE FUTURE, I'LL TAKE MY HUNCHES MORE SERIOUSLY!

Data retrieved from NASA's ASRS site as of July 2007 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.