by tx_swordguy » Fri May 11, 2018 11:10 am
Hi guys, I bought glenn's red sonex 889AP last month and have been going through it, flying when the winds allow. I have an issue with radio noise. I thought is might be the antenna so I pulled the antenna off, cleaned all the paint off the top of the turtle deck, also cleaned the bottom of the antenna base as well as put star lock washers on the underside of the fuselage attachment screws in an effort to get as much ground plane surface connection as possible. It helped only very slightly. I have not been told by the tower there is any transmit issues but on recieve I can only get clear reception on aircraft within 5 miles and tower reception out to about 10 miles. The noise is static in sound, at cruise rpm a plane at 10+ miles is unreadable usually but I get full on static reception breaking the squelch. The tower is readable at 10 miles but far from clear. If I go to idle the static is not as abundant but still there at the same distances. It does NOT sound the same on rpm changes as an alternator whine. I originally thought that the jab 3300 was just loud and the same static at idle was there at cruise and the noise of the engine just made the radio traffic hard to hear. After re-attaching the antenna I am not so sure and think maybe I need to shield something but am unsure where to start. I kinda thought the aluminum cylinder covers for airflow would be enough to shield the spark plugs so haven't done them. Any ideas? distributor, spark plug wires? ??? Specs, sonex a model, jab 3300 1st gen, commit antenna approx 18" behind pilot up top with ELT antenna farther back but ELT not turned on. MGL radio. (have not had a passenger to talk to but just talking into the mic without transmitting I get no static through my side of intercom.) transponder ant on bottom of plane and cannot see a difference if transponder is turned off. The static is always there with engine running as the engine gets louder but hard to differentiate between increase engine noise level and if the static increases with it. I guess I could pull the plane out of the hanger and just turn the radio on without the engine to see if that is truly the issue. Not a super busy airport so may have to sit and wait a while :( When I flew yesterday after cleaning the antenna etc I was able to get a transmission from about 50 miles away which really surprised me, it was quite staticky but readable. I tried aiming the plane in different directions trying to see if reception might be dependant on direction of travel and could not get any definitive findings. Sorry for long post
Mark WHiddon
Mark Whiddon
T25 Aero Estates
Sonex N889AP
jabiru 3300 solid lifter