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Hello Ed & All, I was able to get to the airport for a little while this afternoon to check on a couple of the possibilities that you all have raised. Here's the report: Well, I learned in short order that the ICOM A-23 is indeed useless as a cockpit transmitter (as I also read on this list after I got home!) It was worse than the built-in radio by far, both in transmit & reception. Secondly, I found someone on the field with a volt-meter willing to come use it on my plane. His verdict: good, strong battery, and cigarette lighter tested 12.78 volts. Also, he & an Alon owner looked in the engine compartment and said I have a generator, not an alternator. The same old-timer also owns a watt-meter, and said he could test my antenna, but he did not have it with him today, and I don't know when he will. While taxiing today, using the built-in radio, I did notice a slight bit of static in the reception: nothing that would have bothered me ordinarily, but I'm trying to be sensitive to what it's doing now and report everything. On run-up, there was the same static on L mag, but no static at all on R mag . Ground control reported my transmissions on the ground before take-off were loud and clear -- both with and without the engine running. In the pattern, I was told transmission again deteriorated, but I guess it was still at least somewhat readable, since the tower (a different controller than usual) kept responding as normal, and did not ask me to land or anything (I told her I was going to do trouble-shooting, but could receive her clearly at all times and would land if she told me I'd become unreadable.) I got through 3 landings and a go-round, when I decided to land and change to give the hand-held a try. So, in summary, transmissions seemed to get bad, but not get totally unreadable today. After I landed, on taxi-back, I asked the ground controller how did he read: he said loud and clear -- and that was with the engine still running and taxiing! So I asked if he could please ask the tower controller to specify in what respect the transmissions had gone bad in the pattern. He replied that she wasn't going to have time, but he remembered me and the problem from a couple days ago when he was tower control, and that he remembered them as breaking up, garbled, almost unreadable -- and said he thinks it sounded like something vibration-related. Does any of that help narrow down the likely problem? Thank you, everyone! Especially for taking the time and trouble to write and help me out over a holiday weekend. Linda From: "Ed Burkhead" <[EMAIL PROTECTED]> Reply-To: <[EMAIL PROTECTED]> Date: Sat, 23 Dec 2006 13:08:17 -0600 To: "'Linda Abrams'" <[EMAIL PROTECTED]>, "Ctech" <[email protected]> Subject: RE: [COUPERS-TECH] Re: radio transmitting problem Linda, #7 Aircraft and cars that are called 12 volt are really more complex. While the battery voltage may be 12 volt when the system is off, the regulator normally controls the voltage to be around 13.6 when the vehicle is running and the generator or alternator is giving full output. This charges the battery and it's the optimal voltage for the electronics. (Experts please adjust any misstatements.) #5 & #6. You won't be able to tell any difference between 6 and 10 watts output power. It's there, but it's not so important. The difference between 1.5 and 6 is more than four times and that really shows up. In addition, many of the 1.5 watt transmitters are old (unless they're a handheld) and may produce less power than when new. I've had air-to-air conversations of 125 miles with my 1.5 watt transmitter using an external, aircraft mounted antenna. I've also had problems talking 2-8 miles with Unicom when tracking straight toward the airport due to the airframe shielding the weak signal (the antenna was mounted on the top of the tailcone, just behind the canopy. If I were buying a new panel mount, I'd want 6-10 watts output power. Ah, but is the listed power peak effective power or rms power? Companies usually advertise peak because it's a much bigger number. Experts please comment. I'd guess you web browse the specification pages for a bunch of radios and compare the output power ratings. #1 How many channels does your current radio have? You can check quickly or you may already know. Does the frequency have .x5 only or does it also have .x25 as well as .x5 frequencies? If it has the .x25 frequencies, it's at least a 720 channel radio. It is mandatory (and a very good idea in your area) to have a 720 or 760 channel radio. http://www.swaviator.com/html/issueFM00/avionicsFM00.html 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
