One small funny that we have been working on behind the scenes with ?Tsam? (our RV-3B) has been a low signal strength with the XM receiver whenever the P-Mags are on. Since this isn?t a glider, that pretty much means anytime we?re in flight. The effect has been that weather is sometimes just a little delayed, but more importantly ?Car Talk? is almost impossible to listen to! Tom and Ray are barely coherent when you can hear every word ? having the signal drop out a few times a minutes really leaves you guessing! I am used to the XM music cutting out when I get inverted in a series of aerobatics, but it was pretty annoying to have the drop-outs in straight and level flight.
We went though all the usual electronic troubleshooting, turning circuits on and off on the ground and in the air to isolate the problem. The only thing that made a difference was switching off the P-Mags, so this pretty much nailed the culprit. With the help of the folks at Garmin, we tried a different antenna, different antenna locations, and even a different receiver (built in to the GDU 375 display unit). Nothing made a difference. Brad at P-Mags has been very supportive, but there was little he could do, except ti make sure that we had good connections at all ignition lead ends. I was about ready to start looking into isolating power leads when someone (I think it was Pete Howell), mentioned a similar P-Mag interference problem that was related to a bad connection at the spark plug. He mentioned that the tip on the BR8-ES auto plug may have been loose, and that got me thinking?.
When I installed the initial set of plugs in Tsam before first flight, I happened to have a box of the removable-tip BR8-ES?s on hand, and none of the local auto parts stores had the solid-tip version on hand. I nicked the threads on the plug to keep the screw-on tips secure, and figured I?d change them when I had a chance. Nothing has seemed or felt loose during Phase 1 and up to this point, but since I have now laid in a large supply of the solid tip plugs, I decided to change them out when I got back from my Minnesota trip ? I was doing an oil change anyway.
Lo and behold ? Louise reported that in her 20+ hours of flying out to California and back, she hadn?t noticed any drop-puts at all! I did some local flying this past week, and have only lost signal when upside-down (which, with this airplane, is about half the time I am in the air ? it?s just that much fun!). I have had no problems at all with the 696/XM on the Valkyrie since we installed P-Mags earlier this year ? but I put the solid-tip plugs in the from the start. So I am ready to declare victory on this little problem, and wanted to let folks know that the screw-tip BR8-ES?s might be a place to look if you are getting RFI from your P-Mags. The solid-tips are just a better way to go for several reasons, and this just adds to the list.
Paul
We went though all the usual electronic troubleshooting, turning circuits on and off on the ground and in the air to isolate the problem. The only thing that made a difference was switching off the P-Mags, so this pretty much nailed the culprit. With the help of the folks at Garmin, we tried a different antenna, different antenna locations, and even a different receiver (built in to the GDU 375 display unit). Nothing made a difference. Brad at P-Mags has been very supportive, but there was little he could do, except ti make sure that we had good connections at all ignition lead ends. I was about ready to start looking into isolating power leads when someone (I think it was Pete Howell), mentioned a similar P-Mag interference problem that was related to a bad connection at the spark plug. He mentioned that the tip on the BR8-ES auto plug may have been loose, and that got me thinking?.
When I installed the initial set of plugs in Tsam before first flight, I happened to have a box of the removable-tip BR8-ES?s on hand, and none of the local auto parts stores had the solid-tip version on hand. I nicked the threads on the plug to keep the screw-on tips secure, and figured I?d change them when I had a chance. Nothing has seemed or felt loose during Phase 1 and up to this point, but since I have now laid in a large supply of the solid tip plugs, I decided to change them out when I got back from my Minnesota trip ? I was doing an oil change anyway.
Lo and behold ? Louise reported that in her 20+ hours of flying out to California and back, she hadn?t noticed any drop-puts at all! I did some local flying this past week, and have only lost signal when upside-down (which, with this airplane, is about half the time I am in the air ? it?s just that much fun!). I have had no problems at all with the 696/XM on the Valkyrie since we installed P-Mags earlier this year ? but I put the solid-tip plugs in the from the start. So I am ready to declare victory on this little problem, and wanted to let folks know that the screw-tip BR8-ES?s might be a place to look if you are getting RFI from your P-Mags. The solid-tips are just a better way to go for several reasons, and this just adds to the list.
Paul
