Have people encountered antenna bonding problems and is their a simple fix for these "darn" plastic aeroplanes..:)

Hello Gerard,

 

I've got the following antennae installed internally in our 320 (no external antennae).

 

    VHF com    2

    VHF nav      1

    GPS           1

    Mkr Bcn      1

    TCAD         2

    FM            1

    XPONDR    1

 

TOTAL        9

 

We have had ZERO problems with any of our electronics in 900 hrs. (Thanks Bryant).  All communication is clear and long ranging. I'm no electronic wiz but one suggestion I'd make is to check all of your grounding. All coax should be grounded only at one end. All grounding leads should run to a common ground bus bar and not to each other (no piggybacking). The ground bus bar itself should be connected to the negative battery terminal with substantial grounding strap type cable. 

 

My guess is that proper grounding will go a long way toward solving your radio problem. Good luck.

Gerard,

 

Yeah, what Bill said with a bit more info relative to the ART of fixing interference.

 

1. Fiberglass presents no problem with respect to an antenna's ability to see thru it - Carbon is a different story.  In the LNC2/prepreg airplanes, the main spar caps (top and bottom) contain carbon and certain antennas may not work well buried in the wing outside the aileron bellcrank.  These include DME, Transponder and, perhaps, TCAD.  This may be true of other locations relative to the proximity of the main spar.

 

2. I have only one Comm antenna and use an "antenna switching" device for using the antenna with two comm radios.  The comm antenna is in the vertical stabilizer.

 

3. Some antennae require a ground plane (transponder, ADF, etc).  For example, my high-speed blade transponder antenna is located hanging outside of an outboard wing panel with the ground plane on the inside surface of the wing skin.

 

4. Use the more expensive, but less lossey RG400 antenna rather than the leak prone RG58 - especially for long runs.

 

5. Do not make sharp bends in antenna cable because, under vibration, the center lead can work its way thru the insulator and short against the shield.

 

6.  Some ART:  Currently, my comm uses  leaky RG58 and for a long time I had problems with every temperature readout going crazy when the mike was keyed.  The solution was to move the antenna switcher (thus the two 14" radio coaxs, the device and the antenna coax) about 8 inches away from the problem location - Voila, the problem went away.