Abstract: The present invention provides an apparatus for portable through-the-earth radio (PTTER). The PTTER provides bidirectional voice and/or data communication between a surface radio and a portable radio. The PTTER also provides a transmit antenna having a primary loop and one or more secondary loops configured to increase the magnetic field produced by the primary loop. The PTTER also provides a transportable loop antenna that can be wound around a form for transportation. The PTTER also provides a receive antenna optimal for implementing noise cancellation. The PTTER also provides a navigation subsystem for detecting distance and direction to increase the effective range of the PTTER. The PTTER can be implemented in a backpack form factor.