Fona808 GPS not working, GSM super flaky, GSMLOC just weird

[gogogoch]

I just got a Fona 808 Shield, and I'm running it off an Arduino Uno. I'm using the recommended antennas and a Hologram SIM. I'm running the FONAtest sketch from the Fona library. And things are just not working right.

I've tried it with both a 1200 mAh and 2500 mAh LiPo. The batteries have consistently reported over 90% charge (up to 98%) and over 4100 mV.

1. GPS: I've got it sitting on my windowsill, on a high floor with an unobstructed southern view over Brooklyn. No matter how long I leave it, it never gets a fix.
---> AT+CGNSINF
<--- +CGNSINF: 1,0,19800106004434.000,,,,0.00,0.0,0,,,,,,0,0,,,,,

The raw NMEA shows this:
$GPGGA,004457.021,,,,,0,0,,,M,,M,,*49
$GPGLL,,,,,004457.021,V,N*7B
$GPGSA,A,1,,,,,,,,,,,,,,,*1E
$GPGSV,1,1,00*79
$GPRMC,004457.021,V,,,,,0.00,0.00,060180,,,N*43
$GPVTG,0.00,T,,M,0.00,N,0.00,K,N*32

If I'm reading this correctly, it's not seeing any satellites at all.

I'm using the recommended GPS antenna: https://www.adafruit.com/product/2461. I've inspected the ufl connector and it looks pristine. The antenna is plugged in firmly. I even tried a different passive GPS antenna. No dice. Any ideas?

2. GSM connection keeps dropping.
When I first powered it up, it seemed to connect just fine and AT+CREG? showed "Network status 5: Registered roaming". But after trying a few commands it dropped the connection, showing "Network status 0: Not registered" and then "searching".

Now it is consistently having trouble connecting -- and when it does, it seems to drop the connection as soon as I try to do anything with it. And then it can take 5 or 10 minutes before it reconnects.

I'm using the recommended GSM antenna (https://www.adafruit.com/product/1991), and inspected the ufl connector there. It looks all ok.

3. When GPRS worked (for a short time yesterday), the GSMLOC info was completely wrong.
I was consistently getting this:
---> AT+CIPGSMLOC=1,1
<--- +CIPGSMLOC: 0,-73.983162,40.667641,2019/10/05,07:16:55
Plugging that into google maps... puts me somewhere in Antarctica. (I am actually in Brooklyn.)

I'm really hoping there's some simple fix to all this -- just something I'm doing wrong. But I've followed the guide and I'm using the library as-is and it's not looking good.

[adafruit_support_mike]

$GPGSV,1,1,00*79

If I'm reading this correctly, it's not seeing any satellites at all.

You're reading it correctly. That line translates as "Line 1 of 1, 00 satellites in view."

Your soldering looks excellent, and none of the problems you described would involve the header pins. Could you post a photo showing the component side of the Shield please?

[gogogoch]

Here's the top of the board. Is there something in particular I should be looking at?

Thanks.

[adafruit_support_mike]

I wanted to check the assembly for tombstoned components, marginal solder joints, or any other visible production defects. I don't happen to see any.

Try taking the board to another location and see if it behaves any differently there. The hardware looks good and the symptoms you described could be the effects of RF interference.


BTW - I checked the GPS coordinates in your original post, and they come out a bit west of Prospect Park, on Ninth street. If you're getting Antarctica, you probably have the latitude and longitude swapped.

[gogogoch]

Hi,

I've tried taking the board outdoors, and to the roof of a 26-floor building in south brooklyn. The GPS works on the roof, although that doesn't do any good for my intended application.

But the cellular now is not getting a connection at all, anywhere.

Using your FONAtest sketch, I keep getting either "Network status 0: Not registered" or "Network status 2: Not registered (searching)".

---> AT+CREG?
<--- +CREG: 0,2

Also, in direct serial passthrough (using that sketch) I tried these:

AT+COPS?
+COPS: 0
OK
AT+CSQ
+CSQ: 0,0
OK
AT+CGATT?
+CGATT: 0

I've tried alternate gsm antennas, all to no avail.

I'm going to email customer service about an RMA for this board.

[adafruit_support_mike]

They'll send you a message pointing you back here. The forums are where we diagnose issues and authorize returns.

If you aren't getting any cell reception from the top of the building, where GPS does work, I can call it a problem with the SIM808 radio. Send a note containing a link to this page and your order number to [email protected] and the folks there will get you a replacement. The link is your RMA authorization.

[Fantomaz]

How did this episode end?
(Out of curiosity and for leaning purposes.)