SparkFun Forums

[devpts]

I bought and mounted the Chip scale GPS Antenna.

1.575Ghz VSWR is 1.3 with with return loss at 18.6dB.
Center frequncy as mounted is 1.58Ghz with VSWR at 1.2 and return loss is 20.16dB

Problem: several GPS devices fail to acquire initial data: no position
Solution: Connect alternate antenna for initial fix, remove and connect chip antenna for all subsequante fixes

Questions:
1) What might cause the inital failure
2) How might this be corrected

[leon_heller]

You are not getting enough signal with the chip antenna.

[devpts]

You are not getting enough signal with the chip antenna.

This doesn't make sense as the antenna works fine for subsequent updates.

It just does not work for cold start.

[jremington]

According to the description provided by SparkFun:

the gain is not as great (to be expected), but heck, if you can get a lock with this little guy, who cares?

That is a pretty big "if".

[gm]

This doesn't make sense as the antenna works fine for subsequent updates.

This confirms that the signal is weak as a GPS usually requires a stronger signal to acquire the position and can track a weaker signal. If you look in the specs of the GPS you will notice something like

Tracking Sensitivity -160 dBm
Acquisition Sensitivity -148 dBm

Hope this help,

gm