Hello all,
I am using a Teseo-LIV3 module on my board and curious about performance with regards to cold start. The board is 1 oz copper. The trace going to the U.FL is 36 mil wide and is 218 mil in length from the module to connector. There are no traces running under the module, just copper layers: GND,PWR, Bottom. The ground vias are placed pretty much as per the HW manual's reference for designs. Both power into the module and power from the RF antenna supply out use a 47nH inductor and a 47pF capacitor (0402)
For the trace to the U.FL, I use an online tool to calculate the trace width and it worked out to 36 mil for the frequency, copper weight and epsilon of the board type.
The antenna is a Molex 2066400001 (DK WM21807-ND) . It appears to be quite sufficient in gain and bandwidth to handle the common GNSS bands.
1/4" below the PCB (on standoffs) is a thick aluminum plate so this should be an adequate ground plane.
In cold start the module occasionally takes up to 65 secs to acquire a signal, and on average around 40 to 45. When I say acquire, the time it takes the $GPRMC field to change from "V" to "A" and I have at least 5 satellites in view.
This is light overcast sky restricted only by a plastic cover of the enclosure. According to documents this should be around 30 secs or less. Can someone offer advice or suggestion as to what the problem might be?
Thanks,
Gary
