marchudson
Well Known Member
On how to fix the problem with RFI/EMI.
Components that I have:
GNS430W (Comm 1)
SL-40 (Comm 2)
RG-400 coax cable
2 - RAMI bent whip antennas mounted on belly
Dynon Skyview with EMS module
Single point ground for everything.
Problem I'm having:
When I transmit on comm 1 AND comm 2, the EMS readings go nuts. CHT/EGT moves anywhere from 10 deg to 100 deg depending on the frequency that I'm transmitting. If transmitting on 118.0 I'll get just a little change, on 136.0, I get a huge change. When transmitting on 124.0, the ammeter goes from +8 amps (normal) to -35 amps. Talked to the Dynon folks and they said that I'm the only one with this problem?????
Solutions I've tried:
1. Replacing both cables with store bought cables and routed them in random locations to see if this makes a difference. (no difference noted)
2. Power the Dynon with just the standby battery (no difference). Note Dynon system is still tied to aircraft ground system.
3. Disconnect the sensor wires from the EMS. result - system behaves normally but I don't have any engine monitor readings either. (Maybe noise is not entering EMS module on power supply lines)
4. Place a 12" X 12" piece of aluminum foil on the antenna, touching nothing else but the antenna. (normal indications - I deduce by this that the coax is probably not leaking due to this, don't know)
5. Transmit on Comm 1 and compared results to transmitting on Comm 2. Both radios produce the same adverse results on the EMS.
My next step is to place ferrite chokes on the 3 EMS cables. But is this just putting a bandaid on the problem? I would rather fix the root problem.
OK... I'm open for suggestions. Do I need to purchase a SWR meter or purchase a different brand antenna?
Thanks for your time
Components that I have:
GNS430W (Comm 1)
SL-40 (Comm 2)
RG-400 coax cable
2 - RAMI bent whip antennas mounted on belly
Dynon Skyview with EMS module
Single point ground for everything.
Problem I'm having:
When I transmit on comm 1 AND comm 2, the EMS readings go nuts. CHT/EGT moves anywhere from 10 deg to 100 deg depending on the frequency that I'm transmitting. If transmitting on 118.0 I'll get just a little change, on 136.0, I get a huge change. When transmitting on 124.0, the ammeter goes from +8 amps (normal) to -35 amps. Talked to the Dynon folks and they said that I'm the only one with this problem?????
Solutions I've tried:
1. Replacing both cables with store bought cables and routed them in random locations to see if this makes a difference. (no difference noted)
2. Power the Dynon with just the standby battery (no difference). Note Dynon system is still tied to aircraft ground system.
3. Disconnect the sensor wires from the EMS. result - system behaves normally but I don't have any engine monitor readings either. (Maybe noise is not entering EMS module on power supply lines)
4. Place a 12" X 12" piece of aluminum foil on the antenna, touching nothing else but the antenna. (normal indications - I deduce by this that the coax is probably not leaking due to this, don't know)
5. Transmit on Comm 1 and compared results to transmitting on Comm 2. Both radios produce the same adverse results on the EMS.
My next step is to place ferrite chokes on the 3 EMS cables. But is this just putting a bandaid on the problem? I would rather fix the root problem.
OK... I'm open for suggestions. Do I need to purchase a SWR meter or purchase a different brand antenna?
Thanks for your time