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Author Topic: EM-318-01 EM-318-02 antenna  (Read 3244 times)


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EM-318-01 EM-318-02 antenna
« on: August 31, 2010, 08:40:44 am »

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?


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Re: EM-318-01 EM-318-02 antenna
« Reply #1 on: August 31, 2010, 03:14:29 pm »

For your first inquiry, please refer to this link:

As for your other questions, our engineers stated the following:

1. With the electron switch, the module is able to sense the DC current on the LNA automatically while connecting to an active GPS antenna.

2. If the antenna has a built-in preamp/power supply, it is allowed to put a DC block on it to connect the EM318-01; however, it requires at least 10mA in order to load the current.

3. The EM318-01 needs to sense the DC current to activate the external antenna instead of the patch antenna.
« Last Edit: February 24, 2011, 02:08:28 pm by USG_TECH10 »
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