Datasheet

Active antennas draw current, so they do provide more gain but at a power cost. Check the antenna

datasheet for exactly how much current they draw - its usually around 10-

20mA. (http://adafru.it/960)

Most GPS antennas use SMA connectors, which are popular and easy to use. However, an SMA

connector would be fairly big on the GPS breakout so we went with a uFL connector - which is

lightweight, small and easy to manufacture. If you don't need an external antenna it wont add

significant weight or space but its easy to attach a uFL->SMA adapter cable (http://adafru.it/851).

Then connect the GPS antenna to the cable.

The Ultimate GPS shield will automagically detect an external active antenna is attached and 'switch

over' - you do not need to send any commands

There is an output sentence that will tell you the status of the antenna. $PGTOP,11,x where x is the

status number. If x is 3 that means it is using the external antenna. If x is 2 it's using the internal

antenna and if x is 1 there was an antenna short or problem. On newer shields & modules, you'll

need to tell the firmware you want to have this report output, you can do that by adding a

gps.sendCommand(PGCMD_ANTENNA) around the same time you set the update rate/sentence

output.