Narrative:

On 10/thu/88 I departed 2EJ IFR. I took off north and switched to the assigned frequency 119.3. After several calls and no response, I switched to 124.2 and was able to communication with okc approach control in spite of severe interference on the frequency. (Same interference on 119.3.) they advised that they heard me ok on 119.3, but apparently I was unable to hear them. About 5 mi out, the interference lessened to where it no longer broke squelch. This is normal for about a 5 mi radius of 2EJ. There are about a dozen big radio and tv towers about 1.5 NM to the west and northwest. Sometimes the interference is so bad you can hear music and voice from one of the stations. It reduces reception on all the frequencys used in the area, both unicom and approach control. It's usually impossible to contact approach in the area. Since 2EJ rests under the upper shelf of the okc arsa, it's necessary to be able to talk to approach. Okc approach control is aware of the problem and the supervisor says there is nothing they can do. On arrival to the vicinity of 2EJ, approach typically waits until the last minute to release traffic to unicom because of the proximity of tinker AFB traffic. Consequently, when you are allowed to switch frequencys, you are already in the affected area and communications are difficult or impossible. I live in the same area and I am able to pick up the interference on my scanner. By comparing it to reception on an FM radio, I was able to identify the station causing the trouble as krxo 107.7 FM. The operator at 2EJ talked with the station engineer who seemed cooperative. In the end, he said he could find nothing wrong. It seems to be the typical 'waiting to happen' situation. It's a fairly busy airport and we depend on the traffic calls from aircraft in the area. There are more transients now because of a new race track just opened. When they are unable to communication with unicom or hear the calls from aircraft in the pattern, sometimes they fly a pattern away from the towers, which is frequently wrong causing conflicts. I believe there is something wrong with the FM station. The trouble started within the last 2 or 3 yrs. Any help you can give will be greatly appreciated. Callback conversation with reporter revealed the following: reporter gave additional information concerning this frequency problem. Okc FSDO has communicated the problem to dallas FCC. The FCC office sent a frequency technician to the antenna farm to check the power output and frequency alignment of the radio stations. According to his findings, all the commercial radio stations at the antenna complex are operating in accordance with their FCC license. Okc approach control is as troubled by this lack of communication in the close vicinity of 2EJ. Analyst suggested to reporter that he ask the approach control facility radio technicians to test some other frequencys to see if they are affected by the commercial stations. If some unaffected frequencys can be found, the facility could possibly change frequencys to eliminate this problem. Reporter agreed to do this and report his results in about 3 months.

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Original NASA ASRS Text

Title: GA PLT REPORT OF FREQ INTERFERENCE CAUSED BY COMMERCIAL BROADCAST STATIONS.

Narrative: ON 10/THU/88 I DEPARTED 2EJ IFR. I TOOK OFF N AND SWITCHED TO THE ASSIGNED FREQ 119.3. AFTER SEVERAL CALLS AND NO RESPONSE, I SWITCHED TO 124.2 AND WAS ABLE TO COM WITH OKC APCH CTL IN SPITE OF SEVERE INTERFERENCE ON THE FREQ. (SAME INTERFERENCE ON 119.3.) THEY ADVISED THAT THEY HEARD ME OK ON 119.3, BUT APPARENTLY I WAS UNABLE TO HEAR THEM. ABOUT 5 MI OUT, THE INTERFERENCE LESSENED TO WHERE IT NO LONGER BROKE SQUELCH. THIS IS NORMAL FOR ABOUT A 5 MI RADIUS OF 2EJ. THERE ARE ABOUT A DOZEN BIG RADIO AND TV TOWERS ABOUT 1.5 NM TO THE W AND NW. SOMETIMES THE INTERFERENCE IS SO BAD YOU CAN HEAR MUSIC AND VOICE FROM ONE OF THE STATIONS. IT REDUCES RECEPTION ON ALL THE FREQS USED IN THE AREA, BOTH UNICOM AND APCH CTL. IT'S USUALLY IMPOSSIBLE TO CONTACT APCH IN THE AREA. SINCE 2EJ RESTS UNDER THE UPPER SHELF OF THE OKC ARSA, IT'S NECESSARY TO BE ABLE TO TALK TO APCH. OKC APCH CTL IS AWARE OF THE PROB AND THE SUPVR SAYS THERE IS NOTHING THEY CAN DO. ON ARR TO THE VICINITY OF 2EJ, APCH TYPICALLY WAITS UNTIL THE LAST MINUTE TO RELEASE TFC TO UNICOM BECAUSE OF THE PROX OF TINKER AFB TFC. CONSEQUENTLY, WHEN YOU ARE ALLOWED TO SWITCH FREQS, YOU ARE ALREADY IN THE AFFECTED AREA AND COMS ARE DIFFICULT OR IMPOSSIBLE. I LIVE IN THE SAME AREA AND I AM ABLE TO PICK UP THE INTERFERENCE ON MY SCANNER. BY COMPARING IT TO RECEPTION ON AN FM RADIO, I WAS ABLE TO IDENT THE STATION CAUSING THE TROUBLE AS KRXO 107.7 FM. THE OPERATOR AT 2EJ TALKED WITH THE STATION ENGINEER WHO SEEMED COOPERATIVE. IN THE END, HE SAID HE COULD FIND NOTHING WRONG. IT SEEMS TO BE THE TYPICAL 'WAITING TO HAPPEN' SITUATION. IT'S A FAIRLY BUSY ARPT AND WE DEPEND ON THE TFC CALLS FROM ACFT IN THE AREA. THERE ARE MORE TRANSIENTS NOW BECAUSE OF A NEW RACE TRACK JUST OPENED. WHEN THEY ARE UNABLE TO COM WITH UNICOM OR HEAR THE CALLS FROM ACFT IN THE PATTERN, SOMETIMES THEY FLY A PATTERN AWAY FROM THE TWRS, WHICH IS FREQUENTLY WRONG CAUSING CONFLICTS. I BELIEVE THERE IS SOMETHING WRONG WITH THE FM STATION. THE TROUBLE STARTED WITHIN THE LAST 2 OR 3 YRS. ANY HELP YOU CAN GIVE WILL BE GREATLY APPRECIATED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR GAVE ADDITIONAL INFO CONCERNING THIS FREQ PROB. OKC FSDO HAS COMMUNICATED THE PROB TO DALLAS FCC. THE FCC OFFICE SENT A FREQ TECHNICIAN TO THE ANTENNA FARM TO CHK THE PWR OUTPUT AND FREQ ALIGNMENT OF THE RADIO STATIONS. ACCORDING TO HIS FINDINGS, ALL THE COMMERCIAL RADIO STATIONS AT THE ANTENNA COMPLEX ARE OPERATING IN ACCORDANCE WITH THEIR FCC LICENSE. OKC APCH CTL IS AS TROUBLED BY THIS LACK OF COM IN THE CLOSE VICINITY OF 2EJ. ANALYST SUGGESTED TO RPTR THAT HE ASK THE APCH CTL FAC RADIO TECHNICIANS TO TEST SOME OTHER FREQS TO SEE IF THEY ARE AFFECTED BY THE COMMERCIAL STATIONS. IF SOME UNAFFECTED FREQS CAN BE FOUND, THE FAC COULD POSSIBLY CHANGE FREQS TO ELIMINATE THIS PROB. RPTR AGREED TO DO THIS AND RPT HIS RESULTS IN ABOUT 3 MONTHS.

Data retrieved from NASA's ASRS site as of August 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.