The EM-318-01 appears to have both an integrated patch antenna and also a MMCX external connector, while the EM-318-02 does not have the patch antenna (only MMCX). How does the EM-318-01 decide which antenna to use? The block diagram in the EM-318-01 user manual only shows the external antenna-to-LNA connection. Does the EM-318-01 sense the DC current on the LNA connection to the antenna to automatically switch antennas or is there a mechanical switch somehow through the MMCX connector? If connecting to a GPS antenna that has a built in preamp/power supply, can I put a DC block on it to connect to the EM-318-01 or does the EM-318-01 need to sense the DC current in order to activate the external antenna instead of the patch antenna?