SparkFun Forums

[Anny]

I'm using the EM-406 but it doesn't get any satellite signal . The red LED turns on, and when I connected it to the PC (Hyperterminal), the module sent NMEA messages, but the messages don't have a coordenate. Do I have to return the module to sparkfun? I connected the module to 5V, and the RX pin to 3.3V. The module is connected to the PC through a MAX232. I left the module connected for several minutes and I didn't get anything. Please help me! Does someone has any idea ? Thank you for your time!! .

[ohararp]

You will need to transport your em406 outside so that it has a clear view of the sky. Then leave it outside for at least 15 minutes so that the almanac of gps satellite location can be found and stored. Often the em406 can get a signal inside but not always.

[Anny]

Thank you Ryan for your quick reply...

Days ago I read that the em406 need only 48 seconds to get a coordinate, but now you are telling me that I must wait 15 minutes? I bought this module (the most expensive!!) because I was expecting that it can sent me coordinates in a very short time. Tell me more about your experience with the module indoors and outdoors. If someone have any idea or experience please don't be shy and share it!

[ohararp]

Almanac - A data file that contains orbit information on all satellites, clock corrections, and atmospheric delay parameters. It is transmitted by a GPS satellite to a GPS receiver, where it facilitates rapid satellite vehicle acquisition within GPS receivers. Almanac data must be acquired before GPS navigation can begin.

Once you have this info the EM406 will acquire satellites very quickly. The onboard supercap allows you to store this info for future quick startups. The 15 minutes is just a recommended value. Set the em406 outside and wait for the light to blink. It shouldn't take more than a couple of minutes. In a breadboard setup you may have trouble getting a signal. It wasn't until I put the em406 on a pcb did this problem go away. Check out my site for schematics. IF you are interfacing to a 5V uPic you may need to do some logic level shifting.

[RancidWannaRiot]

I'm using the Em-406 for a project.. and i experienced the same ting when i got it..

i left it on (indoors) for 1 hour and it never got a lock...

i took it outside.. it got a lock after 30 minutes..

but after that.. i can get locks pretty fast..

indoors i get locks in like 5-10 minute.. outdoors i get locks much faster..