External GPS antenna question

[Mikhail Umorin]

Hello --

I want to buy an external GPS antenna and would like to know what is the 
difference between "active", passive (?), powered, and amplified antennas 
(antennae). 

What are the implications of their use with FR (power consumption, 
performance, etc)?

Which ones of the above "should" work in FR?

"Should" any antenna with MMCX connector work in FR?

Thank you for your time, 

Mikhail.

P.S. I checked http://wiki.openmoko.org/wiki/External_GPS_antennas but I want 
to know more of the general info.