Here is an Arduino based electronic compass with a local OLED display, the magnetometer sensor can be mounted on a radio antenna and can output antenna heading to a PC and a local OLED.
This same circuit could be incorporated into a True bearing compass if mounted in a small case with a 9 volt battery. For purposes of demonstration the photo shows an Arduino nano with digital OLED display and a GY2713 magnitometer ,which is a break out board for the HMC5883L chip set.
The circuit diagram is included along with the Arduino sketch code, which is a combination of Adafrut's OLED and magnetometer libraries as found in the Arduino IDE.
For source code please follow this link to my google documents shared folder:
