[aprssig] EMI Help

[Andrew Rich]

Ok I built a GPSiiLCD display. works fine on the bench
throw it in the car , drive off down the road
works for about 5 kms
random characters start to creep in.
then the whole thing just gets worse - until it unusable - grabage all over
the screen
even ran it on battery and 12volts from the car .
the project is in a plastic case
any body had probs with hamhuds and EMI ?
i have grounded the shield from the gps to the unit
maybe i can try some caps across the bus lines ?
Any body an expert on EMI ?

Cheers Andy VK4TEC