Hello Guilhermepilot,
I have not used the Monroy Traffic Watch but this is my understanding how the device functions.
The Monroy Traffic Watch relies on a directional antenna (ANT-300) to provide the axmith information, many of the traffic direction sensing devices use multiple phased antennas to provide the azimuth information, Monroy is able to provide the information with one antenna.
I believe using a simple rod and ball omnidirectional antenna will render the azimuth function of the unit inoperative.
Appears I'm too slow on the keyboard, Vern already provided the answer.