I have to agree with BMathews, CDIs can cause a lot of radio frequency interference, and receivers have to be placed as far away from the CDI as possible. 2.4 GHZ receivers are "less" likely to have problems than 72 MHZ, but can still be interfered with. It is definitely possible that the aluminum plate was "transmitting" the RFI to the components mounted to it. From personal lessons learned, always range test while running your engine at full throttle.