---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 08/31/15: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:41 AM - Re: Re: Request for some direction and advise (Robert L. Nuckolls, III) 2. 06:52 PM - Re: Re: Request for some direction and advise (Bill Bradburry) ________________________________ Message 1 _____________________________________ Time: 08:41:45 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: RE: Request for some direction and advise At 10:15 PM 8/30/2015, you wrote: >I saw where someone else on the list a while back was discussing >adding that connector to their TruTrak at the company's >suggestion. It is supposed to keep RFI out as I recall. > >The antenna is glassed in and not removable, I tried to attach it >with tape, but I could not get it to stay in place so I just glassed >it in. I do have a second antenna that I could try if I don't find >anything with the coax. I only have a Volt-Ohm meter so I don't >think I could bench test the antenna. > I feel your 'pain' . . . more than once I have been presented with a conundrum with tools and test equipment out of reach. Do the touchy-feely things with the feed line first. Then consider building a test antenna. A simple dipole, fed at center with a length of coax fited with BNC cable-female to reach across the aircraft to the opposite side where you can tape it in place. See if the problem resolves. I don't know any specifics about the antenna you have installed. I have been made aware of several products like it wherein the manufacturer thought it a good idea to include a balun/matching transformer in that little potted box at the center. On such product could not handle the power from the transmitter and failed the balun after some hours in service. We're grasping at straws here but one of those straws IS the short one. Without useful diagnostic tools . . . it's the best we can do. But if it's any consolation, I've encountered ONLY ONE EMC problem on an airplane wherein root cause could NOT be resolved . . . only swapped out. Emacs! Seems that some really nifty technology advances in communications hardware were installed on an aircraft being manufactured to still adequate methods designed 40 years ago. A technology that placed NEW and exceedingly difficult requirements on the airframe. From that time to this day, the aircraft has suffered a host of EMC problems that occur at intervals, sometimes in small batches, and will never be resolved except that the old wire-type antennas be re-installed. I'm not suggesting that your situation is intractable . . . only that not all combinations of hardware are plug-n-play in all airframes and yours is fixable. Only spent a few hundred $K tracking the other one down . . . yours will be MUCH less expensive. Bob . . . ________________________________ Message 2 _____________________________________ Time: 06:52:39 PM PST US From: "Bill Bradburry" Subject: RE: AeroElectric-List: RE: Request for some direction and advise I checked the connectors at the two ends of the com coax. They were both well connected to the shield and I couldn't pull them off the cable. The, I guess you would call it the barrel, of the connector at the radio end was a little difficult to twist after the connector was removed. I twisted it back and forth a little and it seemed to loosen up. I suppose there could have been some corrosion where it rotates, but I didn't see anything. I checked and found the radio backing plate had continuity with ground. There is a card edge connector that is used as a shield ground connector at the backing plate that seemed to me to be a loose fit. I mean it was easy to remove it from the plate it connects to. It is held in place by a couple of screws so there was no danger of it falling off, but it was a loose fit so I suppose that some of the pins could have not been making good contact. I don't know if any of the shields that are in this connector could have caused the problem. I wonder if I should try and bend the pins so that they make a tighter fit? Also should the edge it slips over be brightened up some? It is the same grey color as the backing plate? I found another RG-400 cable with connectors on both ends that I could use to hook up the other antenna I have to see if that helps. I don't know if the spare cable will reach to the existing antenna. If it does I could try that as well. Bill _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Monday, August 31, 2015 10:40 AM Subject: RE: AeroElectric-List: RE: Request for some direction and advise At 10:15 PM 8/30/2015, you wrote: I saw where someone else on the list a while back was discussing adding that connector to their TruTrak at the company=12s suggestion. It is supposed to keep RFI out as I recall. The antenna is glassed in and not removable, I tried to attach it with tape, but I could not get it to stay in place so I just glassed it in. I do have a second antenna that I could try if I don=12t find anything with the coax. I only have a Volt-Ohm meter so I don=12t think I could bench test the antenna. I feel your 'pain' . . . more than once I have been presented with a conundrum with tools and test equipment out of reach. Do the touchy-feely things with the feed line first. Then consider building a test antenna. A simple dipole, fed at center with a length of coax fited with BNC cable-female to reach across the aircraft to the opposite side where you can tape it in place. See if the problem resolves. I don't know any specifics about the antenna you have installed. I have been made aware of several products like it wherein the manufacturer thought it a good idea to include a balun/matching transformer in that little potted box at the center. On such product could not handle the power from the transmitter and failed the balun after some hours in service. We're grasping at straws here but one of those straws IS the short one. Without useful diagnostic tools . . . it's the best we can do. But if it's any consolation, I've encountered ONLY ONE EMC problem on an airplane wherein root cause could NOT be resolved . . . only swapped out. Emacs! Seems that some really nifty technology advances in communications hardware were installed on an aircraft being manufactured to still adequate methods designed 40 years ago. A technology that placed NEW and exceedingly difficult requirements on the airframe. From that time to this day, the aircraft has suffered a host of EMC problems that occur at intervals, sometimes in small batches, and will never be resolved except that the old wire-type antennas be re-installed. I'm not suggesting that your situation is intractable . . . only that not all combinations of hardware are plug-n-play in all airframes and yours is fixable. Only spent a few hundred $K tracking the other one down . . . yours will be MUCH less expensive. Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.