I'm trying to interface a GPS receiver with a Minnowboard Turbot Single Board Computer via a ttl serial UART on the boards expansion header but there is a substantial amount of noise on the UART and power pins coming from the Minnowboard and it is causing very low SNR values in the GPS device and the GPS never gets a fix. Moving the GPS device or antenna further from the board doesn't work, the noise is being transmitted through the header pins themselves.
What kind of circuitry do I need[0] to build to isolate the GPS from the interference on those pins?
[0] I've already tried putting ferrite beads on all the connections tx, rx, pwr, gnd to the GPS but it didn't improve the situation enough to get a GPS lock.
Best Answer
How high a resistance can you place in those UART lines? 1Kohms? 10Kohms?
Notice I've created a low-resistance (but not ZERO-resistance) ground path, at bottom of the schematic.
simulate this circuit – Schematic created using CircuitLab