Hi Dave,
Actually the R1655 sensor is actually 2 HAL effect transistors and a permanent magnet so there are no coils. The compass works next to a 5 watt 1.2GHZ transmitter with no effect. On the compass PC board the sensor is mounted right on top of the A/D converter to keep the connections as short as possible just to avoid any noise since the compass is in an R/C submarine with a lot of DC motors and there is a bypass capacitor on the same board with the sensor and A/D. I used two each 3-wire shielded audio cables between the compass and the PIC. I believe you would be just fine and you could also include some ferrite beads if you wish. Hope this helps, Ed