---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 09/02/15: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:45 AM - Re: Request for some direction and advise (Eric M. Jones) 2. 10:54 AM - Re: Re: Request for some direction and advise (Robert L. Nuckolls, III) 3. 11:44 AM - Tesla Meter App and Magnetism (Don Johnson) 4. 01:42 PM - Re: Re: Request for some direction and advise (C&K) 5. 05:43 PM - Re: Tesla Meter App and Magnetism (user9253) 6. 06:43 PM - Re: Re: Tesla Meter App and Magnetism (Charlie England) 7. 06:45 PM - Re: Re: Tesla Meter App and Magnetism (Charlie England) 8. 08:01 PM - Re: Tesla Meter App and Magnetism (user9253) 9. 09:04 PM - Re: Re: Tesla Meter App and Magnetism (Tim Olson) 10. 09:31 PM - Re: Re: Request for some direction and advise (Bill Bradburry) 11. 09:38 PM - Re: Re: Tesla Meter App and Magnetism (Jim Kale) ________________________________ Message 1 _____________________________________ Time: 06:45:41 AM PST US Subject: AeroElectric-List: Re: Request for some direction and advise From: "Eric M. Jones" My Father (who worked on Westinghouse's part of the USN Vanguard rocket), related to me the ultimate failure with it: Test techs would unplug all the tubes (yes it had tubes) test the tubes and stick them back into their sockets....time after time after time. (One thinks they must also have unplugged every module too). So everything tested fine, and when the rocket took off, all the vibration caused the tube sockets to quit making contact because they were worn out. Whether or not this was entirely true, the lesson remains: Contacts are the first place to look for most sorts of electrical problems. For the remainder, contacts probably had something to do with the failure in the first place. Contact failure can occur in ways you would never suspect. In the medical field people get shocked because the plating has worn off brass contacts, which now behave as diodes. The HF used in surgery ("Bovies") now generates HV DC instead of the HF AC used in electrosurgery. OUCH! So always suspect connections first. Both intended and unintended. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=446683#446683 ________________________________ Message 2 _____________________________________ Time: 10:54:18 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: RE: Request for some direction and advise >One other thing that I just thought of that may be a factor. The >backing plate through connectors that the radio slides into when it >is inserted into the tray are very wobbly. It is very easy to make >a circle with them that is at least 1/8 inch in radius. I have >never thought about these connectors before because I thought that >they were wobbly in order to line up with the radio when in is >inserted. But now thinking about it, it seems to me that they >should firm up when the radio is inserted because they are making >rigid contact with the radio?? Mine are still wobbly after the >radio is inserted. Could these connectors or the backing plate be >somehow incorrectly installed? Tray connectors often 'float' on the tray itself so as to accommodate dimenational differences between tray and radio as the radio is slid into the tray. Similarly, your antenna connectors a the back of the radio may appear 'loose' in spite of having perfect electrical integrity. http://tinyurl.com/qa5hr7l In the image sited above, we see where electrical integrity is achieved as a separate component of mechanical mounting. A BNC connector attached to an appliance. http://tinyurl.com/pmy4hsg In the video above, we see that a connector is "loose" to move in some regard while mantaining electrical integrity of the connection. > >Does anyone know if these connectors should be firm after the radio >is installed? Could this be where I have a bad connection with the shield? The connections I am most concerned about are between the coax shield and it's terminating connector. > >What about the other shield grounds described below? Would they be >a factor if that card edge connector does not make a firm >connection? There is a boss just to the side of this card edge >connector that I am considering using to run a separate ground wire >from the backing plate to the "forest of tabs" ground block. Are >there any opinions on this idea? Your symptoms scream of antagonistic disruption of TWO different systems that suggest a problem with the level of RF in the cockpit due to an antenna system problem . . . not with the radio's power/signal wires. Bob . . . ________________________________ Message 3 _____________________________________ Time: 11:44:28 AM PST US From: "Don Johnson" Subject: AeroElectric-List: Tesla Meter App and Magnetism About a year ago when flying my RV-9A to Air Venture, I noticed after departing a small airport in Ohio and preparing to fly over Lake Michigan, that my vertical card compass was stuck on 230 degrees. I used the GPS heading to reorient my DG and went on my way=85 Upon returning home, I decided to replace that compass with one mounted on the center support to the roll bar. Same problem ' stuck on 230 degrees + or ' 10 degrees. Now in the middle of upgrading from steam gauges to Dynon 180, etc., I ran across an Iphone App called Tesla Meter on the App store. There are at least 10 similar apps that point to a source of magnetism and give a strength reading in a measurement referred to as =B5T. Moving it around the cockpit, the signal was very strong and pointed to the junction of the roll bar and fuselage ' readings of approximately 500 =B5T on the both the left and right junctions of the fuselage and the roll bar. The remainder of the roll bar and the support showed readings of 60 to 70 =B5T. While I was at it, I checked other steel pieces around the plane and found two bars on the motor mount with readings in the 400+ =B5T range. Knowing this group is far more informed than I am, I pose the following questions: 1. Is the high reading at the mounting points of the roll bar the likely cause of the stuck compass? 2. Can you offer an explanation as the why those areas show a high reading? 3. If those areas are the problem, how do I correct it? Thanks for your help. Don Johnson RV-9A ________________________________ Message 4 _____________________________________ Time: 01:42:10 PM PST US Subject: Re: AeroElectric-List: Re: Request for some direction and advise From: C&K I love this story Eric Of course I just spent two days tracking a glitch that turned out to be a poor digital signal connection in a good looking shiny solder joint... Ken do not archive On 02/09/2015 9:43 AM, Eric M. Jones wrote: > > My Father (who worked on Westinghouse's part of the USN Vanguard rocket), related to me the ultimate failure with it: > > Test techs would unplug all the tubes (yes it had tubes) test the tubes and stick them back into their sockets....time after time after time. (One thinks they must also have unplugged every module too). > > So everything tested fine, and when the rocket took off, all the vibration caused the tube sockets to quit making contact because they were worn out. > > Whether or not this was entirely true, the lesson remains: Contacts are the first place to look for most sorts of electrical problems. For the remainder, contacts probably had something to do with the failure in the first place. > > Contact failure can occur in ways you would never suspect. In the medical field people get shocked because the plating has worn off brass contacts, which now behave as diodes. The HF used in surgery ("Bovies") now generates HV DC instead of the HF AC used in electrosurgery. OUCH! > > So always suspect connections first. Both intended and unintended. > > -------- > Eric M. Jones > www.PerihelionDesign.com > 113 Brentwood Drive > Southbridge, MA 01550 > (508) 764-2072 > emjones(at)charter.net > > ________________________________ Message 5 _____________________________________ Time: 05:43:19 PM PST US Subject: AeroElectric-List: Re: Tesla Meter App and Magnetism From: "user9253" I have not actually tried this but a knowledgeable person told me that a soldering gun (NOT iron) can be used to demagnetize steel. The object to be demagnetized is passed through the soldering gun heating element loop while the gun trigger is pulled. Of course an airframe is too big, but maybe the soldering gun heating element can be removed from the gun, then placed around the steel tube, then connected back onto the soldering gun. Then the soldering gun trigger is pulled while moving the gun back and forth along the steel tube. If that is not feasible, then maybe someone else knows how to make a demagnetizer using the same principle. Here is a youtube movie about making a demagnetizer: https://www.youtube.com/watch?v=8kKTJQTyX-w Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=446707#446707 ________________________________ Message 6 _____________________________________ Time: 06:43:58 PM PST US Subject: Re: AeroElectric-List: Re: Tesla Meter App and Magnetism From: Charlie England On 9/2/2015 7:41 PM, user9253 wrote: > > I have not actually tried this but a knowledgeable person told me that a soldering gun (NOT iron) can be used to demagnetize steel. The object to be demagnetized is passed through the soldering gun heating element loop while the gun trigger is pulled. Of course an airframe is too big, but maybe the soldering gun heating element can be removed from the gun, then placed around the steel tube, then connected back onto the soldering gun. Then the soldering gun trigger is pulled while moving the gun back and forth along the steel tube. > If that is not feasible, then maybe someone else knows how to make a demagnetizer using the same principle. > Here is a youtube movie about making a demagnetizer: > https://www.youtube.com/watch?v=8kKTJQTyX-w > Joe > > -------- > Joe Gores Find a TV repair shop that's been around since before flat screens (tube type days). Ask if they still have their degaussing coil (mine's still packed away somewhere, after closing the shop 20 years ago). ________________________________ Message 7 _____________________________________ Time: 06:45:36 PM PST US Subject: Re: AeroElectric-List: Re: Tesla Meter App and Magnetism From: Charlie England On 9/2/2015 7:41 PM, user9253 wrote: > > I have not actually tried this but a knowledgeable person told me that a soldering gun (NOT iron) can be used to demagnetize steel. The object to be demagnetized is passed through the soldering gun heating element loop while the gun trigger is pulled. Of course an airframe is too big, but maybe the soldering gun heating element can be removed from the gun, then placed around the steel tube, then connected back onto the soldering gun. Then the soldering gun trigger is pulled while moving the gun back and forth along the steel tube. > If that is not feasible, then maybe someone else knows how to make a demagnetizer using the same principle. > Here is a youtube movie about making a demagnetizer: > https://www.youtube.com/watch?v=8kKTJQTyX-w > Joe > > -------- > Joe Gores > > Add to my previous post: don't forget to remove the compass & anything else that might get trashed by a big magnetic field (AHARS units, magnetometers, etc). ________________________________ Message 8 _____________________________________ Time: 08:01:32 PM PST US Subject: AeroElectric-List: Re: Tesla Meter App and Magnetism From: "user9253" Found this on the internet about demagnetizing: > What if you could put many wraps of insulated wire around the pipe and connect an AC welder to the wire. The longer the wire the better and of course the wire will have to handle the amps you feed it with the welder. Move the coil of wire down the length of the pipe. Don't see why this wouldn't work. LOL George -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=446710#446710 ________________________________ Message 9 _____________________________________ Time: 09:04:38 PM PST US From: Tim Olson Subject: Re: AeroElectric-List: Re: Tesla Meter App and Magnetism I would suggest also posting to the RV list. I don't know a lot about it but a few years ago I read many posts regarding degaussing canopy frames. I think the people built their own degaussers even, perhaps. I guess a lot of the RV's with metal frames had some residual magnetism and people would degauss them and get them back to much less magnetic. Also, maybe try searching the matronics archive via the web login. Tim On 9/2/2015 7:41 PM, user9253 wrote: > > I have not actually tried this but a knowledgeable person told me that a soldering gun (NOT iron) can be used to demagnetize steel. The object to be demagnetized is passed through the soldering gun heating element loop while the gun trigger is pulled. Of course an airframe is too big, but maybe the soldering gun heating element can be removed from the gun, then placed around the steel tube, then connected back onto the soldering gun. Then the soldering gun trigger is pulled while moving the gun back and forth along the steel tube. > If that is not feasible, then maybe someone else knows how to make a demagnetizer using the same principle. > Here is a youtube movie about making a demagnetizer: > https://www.youtube.com/watch?v=8kKTJQTyX-w > Joe > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=446707#446707 > ________________________________ Message 10 ____________________________________ Time: 09:31:47 PM PST US From: "Bill Bradburry" Subject: RE: AeroElectric-List: RE: Request for some direction and advise Bob, Success! I thank you for sending me in the proper direction to find this problem. I would never have figured out that it was RF loose in the cockpit. While I was checking for where I could possibly have a loose connection this afternoon, I removed the radio from the tray and measured both the length of the radio and the distance it had to reach to the connectors in the back plate. Whoops! Looks like the radio needs to be seated deeper into the tray! Stupid builder tricks! When I installed the radio, I installed a bezel around them and to make it look nicer, I put the bezel under the faceplate on the radio. The radio passed the test Garmin has for that, (three turns of the screw after the radio powers on) but apparently over time it got looser and looser and started having more and more symptoms. I modified the bezel this afternoon so the radio would properly seat and the problem appears to have resolved. I was getting a huge RF leak from the back of the radio prior to it getting into the coax. I am completing my conditional inspection so it will be a few days before I can fly and see just what symptoms I have fixed. Thanks, Bob! Bill _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Wednesday, September 02, 2015 12:53 PM Subject: RE: AeroElectric-List: RE: Request for some direction and advise One other thing that I just thought of that may be a factor. The backing plate through connectors that the radio slides into when it is inserted into the tray are very wobbly. It is very easy to make a circle with them that is at least 1/8 inch in radius. I have never thought about these connectors before because I thought that they were wobbly in order to line up with the radio when in is inserted. But now thinking about it, it seems to me that they should firm up when the radio is inserted because they are making rigid contact with the radio?? Mine are still wobbly after the radio is inserted. Could these connectors or the backing plate be somehow incorrectly installed? Tray connectors often 'float' on the tray itself so as to accommodate dimenational differences between tray and radio as the radio is slid into the tray. Similarly, your antenna connectors a the back of the radio may appear 'loose' in spite of having perfect electrical integrity. http://tinyurl.com/qa5hr7l In the image sited above, we see where electrical integrity is achieved as a separate component of mechanical mounting. A BNC connector attached to an appliance. http://tinyurl.com/pmy4hsg In the video above, we see that a connector is "loose" to move in some regard while mantaining electrical integrity of the connection. Does anyone know if these connectors should be firm after the radio is installed? Could this be where I have a bad connection with the shield? The connections I am most concerned about are between the coax shield and it's terminating connector. What about the other shield grounds described below? Would they be a factor if that card edge connector does not make a firm connection? There is a boss just to the side of this card edge connector that I am considering using to run a separate ground wire from the backing plate to the =13forest of tabs=14 ground block. Are there any opinions on this idea? Your symptoms scream of antagonistic disruption of TWO different systems that suggest a problem with the level of RF in the cockpit due to an antenna system problem . . . not with the radio's power/signal wires. Bob . . . ________________________________ Message 11 ____________________________________ Time: 09:38:17 PM PST US From: "Jim Kale" Subject: RE: AeroElectric-List: Re: Tesla Meter App and Magnetism Way back when TVs had large Picture Tubes, more properly called cathode ray tubes, technicians had coils of wire plugged into 110 volt AC. They waved them all over the television metal chassis. This alternating magnetic field demagnetized the TV. Also called degaussing. Magnetic fields on the TV Chassis would distort the picture. This system could also be used on the metal parts of an airplane. However, if you don't know what you are doing, you could easily demagnetize some parts that need their magnetic fields to operate properly. Yes, like the compass, but possibly also some delicate and expensive avionics. Let the experimenter beware!! -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Charlie England Sent: Wednesday, September 2, 2015 8:45 PM Subject: Re: AeroElectric-List: Re: Tesla Meter App and Magnetism --> On 9/2/2015 7:41 PM, user9253 wrote: > --> > > I have not actually tried this but a knowledgeable person told me that a soldering gun (NOT iron) can be used to demagnetize steel. The object to be demagnetized is passed through the soldering gun heating element loop while the gun trigger is pulled. Of course an airframe is too big, but maybe the soldering gun heating element can be removed from the gun, then placed around the steel tube, then connected back onto the soldering gun. Then the soldering gun trigger is pulled while moving the gun back and forth along the steel tube. > If that is not feasible, then maybe someone else knows how to make a demagnetizer using the same principle. > Here is a youtube movie about making a demagnetizer: > https://www.youtube.com/watch?v=8kKTJQTyX-w > Joe > > -------- > Joe Gores Find a TV repair shop that's been around since before flat screens (tube type days). Ask if they still have their degaussing coil (mine's still packed away somewhere, after closing the shop 20 years ago). ------------------------------------------------------------------------------------- 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.