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Larry, The only time we tried this in trouble-shooting was right after flying the pattern for a half-hour or so, and taxiing back to the A&P's hanger. When I did routine shut-down, it did include turning off the Avionics switch & Master switch. Then the A&P got the idea to test transmission with the engine off, first by me talking to him from the plane's radio and he listened via the hand-held, and second by my calling Ground Control. To do those, I had turned on only the Avionics switch and Master switch again, without re-starting the engine. Both Ground & he could hear me ok with the engine off. We only did this once, but the difference was very noticeable. I would have liked to replicate this a few more times, but he had to leave. Linda From: Larry Snyder <[EMAIL PROTECTED]> Date: Fri, 22 Dec 2006 15:21:53 -0600 To: Linda Abrams <[EMAIL PROTECTED]> Cc: Ctech <[email protected]> Subject: Re: [COUPERS-TECH] radio transmitting problem Remember, capacitors dry out with age, particular ones of that vintage. I would look at the radio having problems after building up a charge in the caps, or it could be vibration-related. If transmission clears up as soon as the engine is turned off, without turning the radio off and on, then I would be suspicious about vibration, again a bugaboo in old radios, as solder joints deteriorate, etc. No expert, but I've used lots of really old stuff in my time... Larry N99340 Larry Snyder [EMAIL PROTECTED] On Dec 22, 2006, at 3:11 PM, Hartmut Beil wrote: ----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]---- Ed. I discussed the problem with Linda off list a bit and it turns out that the radio works fine again after been turned off for a minute or so. This indicates to me that something inside the radio is maybe getting warm or a capacitor is charging up or what have it that disables the radio when in use over time. A replacement is on the way thanks to Wayne and if the problem persists with Wayne's radio, one can look outside of the radio, if the problem is gone, I guess Wayne will make a sweet deal for Linda. Hartmut ----- Original Message ----- From: Ed Burkhead <mailto:[EMAIL PROTECTED]> To: 'Linda Abrams' <mailto:[EMAIL PROTECTED]> ; Ctech <mailto:[email protected]> Sent: Friday, December 22, 2006 10:03 PM Subject: RE: [COUPERS-TECH] radio transmitting problem ----[Please read http://ercoupers.com/disclaimer.htm before following any advice in this forum.]---- > 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? 2. Is the problem that the tower and other planes can¹t hear you when you are a. on the ground taxiing out for takeoff? b. in the pattern? c. at certain points in the pattern? d. outside the pattern? 3. Does the signal quality a. stay the same throughout the flight? b. slowly decay throughout the flight? c. get sometimes bad, sometimes better? d. relate to engine power level? (i.e. if you reduce power to idle, does it help?) 4. Any relationship in which way the plane is pointed relative to the tower? 5. Are you using an intercom? If so, is it 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? 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. Your responses to #1, #2 and #3 will give us a lot more to go on. Ah, ain¹t debugging fun? 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 ============================================================================ == To leave this forum go to: http://ercoupers.com/lists.htm ============================================================================== To leave this forum go to: http://ercoupers.com/lists.htm
