Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Page 2 of 2 FirstFirst 12
Results 11 to 13 of 13

Thread: intercom noise?

  1. #11

    Join Date
    Nov 2014
    Location
    Gainesville, tx
    Posts
    79

    Default Re: intercom noise?

    rotax 582 facet electric fuel pump. noise is only there when the fuel pump is turned on. if it is off the noise is gone. I can keep the radio/intercom switch on and turn other switches off and it is isolated to the intercom for some reason. I bypassed the intercom and went straight to the handheld with no problems. The same power wire powers both the intercom and the radio charging station. I am only assuming but I feel there is enough power absorbtion going through the radio charger into the radio battery and finally out the radio to filter out the noise that way but for some reason it is pulsing through the intercom. I just tried putting an 1800uf capacitor on the radio power and it did not work. I am thinking I may put a higher capacitor on the fuel pump to see if that may do something. Any ideas on what capacitor?

  2. #12
    Guy Buchanan's Avatar
    Join Date
    Mar 2009
    Location
    Ramona, CA
    Posts
    119

    Default Re: intercom noise?

    I'll reply, since nobody else offered this suggestion. (Got to keep you busy!) I had noise problems from the 912 regulator I mounted behind the firewall. Talking to Bob Nuckols over at Aeroelectric he was adamant that my only problem was a ground loop. After shielding the entire world, I finally got serious about isolating ground loops, found one, and of course fixed the problem.

    Problem was, I thought I had been very careful about single path grounds. It only took one. What I did was use a ohm-meter to check every ground path, disconnecting each ground wire from the ground bus one at a time. I finally found one that grounded with its ground wire disconnected. That was the loop I needed to isolate. This should offer you hours of enjoyment. (Kidding!)

    One more thing. I think you asked about isolating power from signal wires. According to Nuckols, this is always a good idea. It's also a good idea to twist or braid power and ground wires to help eliminate any transmission, and to shield any signal wires, grounding the braid at only one end. (No ground loops!)

    Good luck! And I highly recommend checking in with the Aeroelectric Connection on Matronics if you get really frustrated; Bob's still incredibly helpful. (Amazing since he's probably heard every question a hundred times in the last 20 years.)
    Guy Buchanan
    San Diego, CA
    Deceased K-IV 1200 / 912uls / 70" Warp 3cs

    gebuchanan@cox.net

  3. #13

    Join Date
    Nov 2014
    Location
    Gainesville, tx
    Posts
    79

    Default Re: intercom noise?

    Guy, Thanks for the info. Not being the smartest guy in regards to the testing of electrical equipment could you explain how you use an ohm meter for that? I understand checking voltage on a dc circuit. Just unsure how checking ohms will find a ground loop in this regard. I would assume you place one lead on the ground bus and one lead on the disconnected grnd wire and if you get a reading other than infinity you have a loop is this correct? Would it make a difference at what setting you put the ohm meter? I will also pull my pump wires out again and twist the whole strand and then put it in braid. I just ordered a 500mf capacitor to put at the pump thinking that may help. I will keep trying and if I can fix it I will give an update otherwise I may keep pestering you guys

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •