[SOLVED] GX400 - GPS doing nothing at all

We are testing a new Sierra Wireless AirLink GX400. We got a dual-purpose antenna to access VZW cell network and GPS. We have good cell signal, but absolutely no GPS at all.

I have found very little help so far, but here is what I’ve tried:

  1. set GPS functions to log in Debug mode.
  2. cold-boots and warm boots
  3. swap cellular and GPS leads from the antenna
  4. turn off the Diversity/Aux antenna connection in ACEmanager
  5. tried both Standalone and MS-based GPS modes.

Is there a configuration trick that I am missing?

Could it be a bad antenna? Or is there some activation process to get GPS going that our salesman forgot to mention?

I also have a call in to tech support, but thought I would ask here to see if others have “been there / done that / got the Tee-shirt”

Thanks for any help or advice you can offer!



Our building is metal, and my office is interior. I just needed a window to allow us to get a lock.

Thank you for posting the good news !
It is true that to get a GPS fix it is needed to have a pretty clear environment (eg. not in a cave or in metal buildings that are acting like a Faraday cage)

It’s generally hard to get a GPS fix even inside a non-metal building!

Install a GPS repeater and you can have fun watching the GPS get fix even without any antenna :smiley: :smiley:
gps-repeating.com/en/product … nu-66.html

GPS repeaters may require a license or they may not be used in your country. Check licensing conditions with the local (radio) authorities before operating the GPS repeater product.

Surely, you’d still need an antenna to received the signal from the repeater?

And the fix reported would, presumably, be the position of the repeater’s antenna - not the position of your unit?

I suppose you can consider the traces on the PCB as antenna.
On various occasions I have gotten a fix without any specific GPS antenna connected, if I was close (4 meters) to the repeater.
Due to this we have to turn off the repeater whenever we need to be sure that the connected antenna is OK.

And yes, it’s the position of the repeaters antenna that is reported.

Still very useful for various purposes.