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Ed, Thanks for your detailed trouble-shooting questions. It is a great template which I will keep. I do not know all the answers, but will answer your Qs below with what I do know, using a different script. Linda From: "Ed Burkhead" <[EMAIL PROTECTED]> Reply-To: <[EMAIL PROTECTED]> Date: Fri, 22 Dec 2006 15:03:26 -0600 To: "'Linda Abrams'" <[EMAIL PROTECTED]>, "Ctech" <[email protected]> Subject: RE: [COUPERS-TECH] radio transmitting problem > Would your idea of "a weak element...in the transmitter" > account for the fact that after flying it a half-hour and > experiencing this problem deteriorating, when I landed > and shut down the engine, then transmissions were > immediately ok again? That is what is so weird to > me about this situation (and to the A&P). Linda, Humm, no. If it¹s immediately OK when you shut down the engine, then, well, we don¹t know enough. Questions: 1. Does the tower (or other plane) hear you a. loud but garbled? b. loud but staticy? c. clear but progressively weaker? d. clear but sometimes weak, sometimes strong? ON 2 DIFFERENT DAYS THEY SAID IT STARTED OUT "ON THE WEAK SIDE, BUT CLEAR." THEN AFTER 2ND TIME AROUND THE PATTERN, THEY BEGAN ASKING ME TO REPEAT, (I THINK THEY WERE SAYING BREAKING UP). ON THE 4TH TIME AROUND, THEY SAID (first day) "SO GARBLED & BREAKING NEARLY UNREADABLE." (second day) "SO MUCH STATIC NEARLY UNREADABLE." It was different controllers every 10 minutes, so exact words may not be representative. I told them both days on takeoff that I'm trouble-shooting a transmission problem & please advise if transmission deteriorates. 2. Is the problem that the tower and other planes can¹t hear you when you are a. on the ground taxiing out for takeoff? THAT WASN'T AN ISSUE ON THE TESTING DAYS, BUT I WAS DOING TOUCH & GO. HOWEVER, THE WEEK BEFORE, WHEN THE PROBLEM FIRST SHOWED UP, I WAS AT CAMARILLO AIRPORT WAITING TO TAXI, AND THEIR TOWER COULD SEE ME BUT SAID THEY COULDN'T HEAR ME. I TAXIED BACK TO GARY DALLUGE'S HANGAR AND SHUT EVERYTHING DOWN, SWITCHED HEADSETS, AND THAT FIRST TIME THAT SEEMED TO SOLVE IT (THAT'S WHY I THOUGHT AT FIRST THAT IT WAS JUST A HEADSET PROBLEM, BUT TROUBLE HAS RECURRED NOW EVEN USING THAT SECONDARY HEADSET.) b. in the pattern? YES. BOTH TEST DAYS WERE TOUCHnGO. FIRST DAY IT LASTED AROUND 6 LANDINGS BEFORE TOWER SAID "YOU'RE UNREADABLE." THE SECOND DAY, ONLY 4. c. at certain points in the pattern? I HAVEN'T TESTED THIS SPECIFICALLY, BUT HAVE THE IMPRESSION THAT IT IS NOT LIMITED TO A PARTICULAR POINT IN THE PATTERN. d. outside the pattern? YES. ON THE TRIP UP TO CAMARILLO (SEE (a) ABOVE) THE OTHER PLANE IN THE L.A. SPECIAL FLIGHT RULES AREA (OVER LAX) SAID THEY COULD NOT READ ME. BUT WHEN I WAS LANDING AT CAMARILLO, TOWER SAID NOTHING ABOUT TRANSMISSION. 3. Does the signal quality a. stay the same throughout the flight? b. slowly decay throughout the flight? YES. c. get sometimes bad, sometimes better? NO; IT ONLY CLEARED UP WHEN I SHUT DOWN THE ENGINE AFTER 1/2 HR. OF TOUCHnGO ON THE FIRST TEST DAY DESCRIBED ABOVE. d. relate to engine power level? (i.e. if you reduce power to idle, does it help?) NO. 4. Any relationship in which way the plane is pointed relative to the tower? NOT THAT I'VE NOTICED 5. Are you using an intercom? If so, is it I WAS THE ONLY ONE IN THE PLANE ON ALL THOSE OCCASIONS, SO INTERCOM WASN'T IN USE. a. Battery or aircraft powered? b. Fresh batteries? 5. Some very old radios like that don¹t handle modern (electret) microphones well. a. Have you tried a separate microphone? I HAVE TRIED 2 DIFFERENT HEADSETS, AND I TRIED THE SECONDARY HEADSET IN BOTH PILOT & CO-PILOT HEADSET JACKS, WITH SEPARATE PTT SWITCHES, SINCE ORIGINALLY I (ERRONEOUSLY) SUSPECTED THE PTT SWITCH. ON THE FIRST OCCASION WHERE THE TRANSMISSION PROBLEM CAME UP (CAMARILLO TRIP, ABOVE) IT SEEMED AT FIRST LIKE USING MY SECONDARY HEADSET SOLVED IT. HOWEVER, ALL SUBSEQUENT DAYS WERE WITH THE SECONDARY HEADSET, AND THE PROBLEM RECURRED. b. Have you tried a separate carbon or dynamic microphone? c. Are you using an old carbon microphone? If so, bang it on something a few times to loosen up the carbon granules. SEE ANSWER TO (a) ABOVE. WHEN I -- AND THE DELTA AVIONICS MAN -- AT FIRST THOUGHT IT WAS THE OLD TELEX-ECHELON HEADSET, I SENT IT IN TO BE SERVICED. IT HAS NOT BEEN RETURNED YET, BUT EVEN USING THE SECONDARY HEADSET (A MACH 1 BANDLESS KIND, <5 MONTHS OLD), THE PROBLEM HAS BEEN REPLICATED ON SEVERAL TEST DAYS. SO, IF THERE *WAS* ANY PROBLEM WITH THE TELEX-ECHELON HEADSET, IT WASN'T THE *ONLY* PROBLEM. Your responses to #1, #2 and #3 will give us a lot more to go on. Ah, ain¹t debugging fun? FRANKLY, I'D RATHER BE FLYING. (BUT I SURE APPRECIATE THE COLLECTIVE DE-BUGGING HELP OF EVERYONE ON THIS LIST TO HELP GET ME BACK UP THERE!) Ed Burkhead http://edburkhead.com ed -at- edburkhead???.com (change -at- to @ and remove "???") ============================================================================== To leave this forum go to: http://ercoupers.com/lists.htm
