---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 10/23/12: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:17 AM - VHF Interference With Wing Leveler (Charles Brame) 2. 10:45 AM - Re: VHF Interference With Wing Leveler (Robert L. Nuckolls, III) 3. 11:32 AM - Re: VHF Interference With Wing Leveler (Robert L. Nuckolls, III) 4. 11:37 AM - Re: VHF Interference With Wing Leveler (Joe Dubner) 5. 11:59 AM - Re: turn coordinator causing noise in headset (David Josephson) 6. 01:54 PM - Re: turn coordinator causing noise in headset (jerrytex) ________________________________ Message 1 _____________________________________ Time: 09:17:15 AM PST US From: Charles Brame Subject: AeroElectric-List: VHF Interference With Wing Leveler I have a NavAid Wing leveler installed in my RV. Works as advertised - most of the time. When I transmit on the radio (Apollo SL-60,) I get a strong right turn input. The input ceases immediately and the wings are abruptly leveled when the transmission stops. The radio antenna is directly below the NavAid servo. The wires to the servo are shielded. Is there any way to filter the interference? By the way, the NavAid company is now defunct and not available for support. Charlie Brame RV-6A, N11CB San Antonio ________________________________ Message 2 _____________________________________ Time: 10:45:27 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: VHF Interference With Wing Leveler At 11:16 AM 10/23/2012, you wrote: I have a NavAid Wing leveler installed in my RV. Works as advertised - most of the time. When I transmit on the radio (Apollo SL-60,) I get a strong right turn input. The input ceases immediately and the wings are abruptly leveled when the transmission stops. The radio antenna is directly below the NavAid servo. The wires to the servo are shielded. Is there any way to filter the interference? By the way, the NavAid company is now defunct and not available for support. I had some discussions with the original owner/designer over this same issue about 15 years ago at OSH. He was reluctant/unable to rise to the design goal of making sure his product would perform as advertised in airplanes with transmitters on board. Shielded wire is of little if any value in fixing an RFI issue. Filtering wires as they enter a shielded environment on the potential antagonist or victim is the time honored approach . . . I don't recall when . . . or even if it happend on this List . . . there was some discussion that I think resulted in a successful 'fix'. Does anyone else on the List recall? Do you have schematics for the black-boxes? Bob . . . ________________________________ Message 3 _____________________________________ Time: 11:32:14 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: VHF Interference With Wing Leveler At 12:44 PM 10/23/2012, you wrote: At 11:16 AM 10/23/2012, you wrote: I have a NavAid Wing leveler installed in my RV. Works as advertised - most of the time. When I transmit on the radio (Apollo SL-60,) I get a strong right turn input. The input ceases immediately and the wings are abruptly leveled when the transmission stops. The radio antenna is directly below the NavAid servo. The wires to the servo are shielded. Is there any way to filter the interference? By the way, the NavAid company is now defunct and not available for support. I had some discussions with the original owner/designer over this same issue about 15 years ago at OSH. He was reluctant/unable to rise to the design goal of making sure his product would perform as advertised in airplanes with transmitters on board. Shielded wire is of little if any value in fixing an RFI issue. Filtering wires as they enter a shielded environment on the potential antagonist or victim is the time honored approach . . . I don't recall when . . . or even if it happend on this List . . . there was some discussion that I think resulted in a successful 'fix'. Does anyone else on the List recall? Do you have schematics for the black-boxes? P.S. ============================================== Text on page 11 of the installation manual found at http://tinyurl.com/9xh5l6r describes the function of a diode added to the PTT line for a transmitter shown on page 9. This apparently serves to 'lock up' the servo during transmit intervals thus preventing the otherwise vulnerable servo from reacting to strong RF. Bob . . . ________________________________ Message 4 _____________________________________ Time: 11:37:45 AM PST US From: Joe Dubner Subject: AeroElectric-List: Re: VHF Interference With Wing Leveler Charlie, The NavAid wing leveler installation instructions show an optional diode and connection to the com radio PTT. With them the A/P is disabled while the PTT is depressed, allowing it to "do nothing" in the event of RFI. NavAid manuals are available here: http://www.porcine.com/gps/sc/ftp_manuals.html -- Joe Independence, OR http://www.mail2600.com/cgi-bin/position.cgi?call=N821RP Charles Brame wrote: > > I have a NavAid Wing leveler installed in my RV. Works as advertised - > most of the time. When I transmit on the radio (Apollo SL-60,) I get a > strong right turn input. The input ceases immediately and the wings are > abruptly leveled when the transmission stops. The radio antenna is > directly below the NavAid servo. The wires to the servo are shielded. Is > there any way to filter the interference? > > By the way, the NavAid company is now defunct and not available for > support. > > Charlie Brame > RV-6A, N11CB > San Antonio > > > > > ________________________________ Message 5 _____________________________________ Time: 11:59:00 AM PST US From: David Josephson Subject: AeroElectric-List: Re: turn coordinator causing noise in headset > > It seems like it is coming in through the antenna but why would turning the landing > light on make it go away. Anyone have any ideas? Filter maybe? You didn't mention whether the noise is there only when receiving a signal or in your headset all the time. This is important. If it's only when you're receiving a signal I would agree with Bob's suggestion that it's radiated, and a filter would help. Turning the landing light on probably drops the voltage sufficiently that the current spikes drawn by the inverter in the t/c are significantly smaller than with the light off. -- David Josephson ________________________________ Message 6 _____________________________________ Time: 01:54:09 PM PST US Subject: AeroElectric-List: Re: turn coordinator causing noise in headset From: "jerrytex" The noise is there always, regardless of transmitting or receiving. I can put my headset on, turn on the master, listen to the gyro spin up in the headset, then turn on the landing the light, and the noise goes away. Or I can disconnect the antenna, and the noise goes away. I read on a yahoo group in which someone else was having the same issue but there was no fix listed. I'll try the CAPACITOR and if that doesn't work, I'll order the filter. Thanks for the responses. 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