Thread: Split XM and GPS Signal (Use only one antenna?)

you might be able to find a combo antenna, but your not going to be able to split the signal from the same antenna

XM and GPS probably use very different frequencies, which means different antenna configurations are required.

I was under the impression that XM also transmitted GPS as a part of their feed. Of course I might be completely off-base here. But I thought frodo's new app used GPS extracted from XM (i only skimmed the site so i may have mis-interpreted).

edit: here's the page
http://www.mp3car.com/tracker/tracker.html

. This page uses a custom XM Radio client that uploads GPS coordinates, Song Info (and soon OBDII data) to a webservice.(Via cell phone) This allows the vehicle to be tracked

I guess it's a bit ambiguos, so I'm not sure if that means you need a seperate GPS source or not.

it is seperate

XM radio only has two geosynchronous satellites. To get any sort of GPS reading, you typically need at least 3 satellites (4 to get altitude).. and even then your accuracy may not get over 200ft. To get the 30ft or better accuracy you need to pull in 6 or more satellites, which most GPS receivers can (I think most can do up to 12 satellites).

XM and GPS run on different frequency ranges as well as different polarization.

Most XM antennas use a active design. The receiver actually powers a small amplifier and filter in the antenna.. external GPS antennas are usually not active.


All of these differences make it practically impossible for both services to share the same antenna.