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Adafruit FONA 808 Shield GPS Problem
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Adafruit FONA 808 Shield GPS Problem

by nunosilvarocha on Tue Mar 05, 2019 7:10 pm

Hi,

I have an Adafruit FONA 808 Shield that has worked perfectly on some tests I've done.
Now i needed the shield again, however the GPS does not work.
I use the Adafruit_FONA Library to do the first tests, the NMEA string is presented but the GPS never fixes the signal (wait more than 1 hour).
I'm doing the outdor tests and using a passive antenna (I already tested the anttena in other modules and it works).

All other functions work correctly.
I have measured the continuity between the antenna connector. Central pin and the SIM808 ok, GND ok.

What could be happening? Can you help?

nunosilvarocha
 
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Re: Adafruit FONA 808 Shield GPS Problem

by adafruit_support_mike on Wed Mar 06, 2019 1:16 am

Post a sample of the raw NMEA sentences after the GPS module has been active for 10-15 minutes please. That will give us a better idea of what it's seeing.

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Re: Adafruit FONA 808 Shield GPS Problem

by nunosilvarocha on Wed Mar 06, 2019 5:52 pm

GPS was active +/- 1 hour
Attached is a RAW NMEA print
Attachments
GPS.png
GPS.png (34.42 KiB) Viewed 174 times

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Re: Adafruit FONA 808 Shield GPS Problem

by adafruit_support_mike on Thu Mar 07, 2019 1:20 am

Thank you.

That says the GPS module only sees one satellite. The most likely reason for that would be a bad connection to the antenna. Double-check to make sure the uFL connector is seated properly and hasn't gotten damaged.

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Re: Adafruit FONA 808 Shield GPS Problem

by nunosilvarocha on Thu Mar 07, 2019 5:11 am

I checked the uFL connector again (visual inspection and with the multimeter), cleaned it with isopropyl alcohol.
I checked the antenna connector.
I went back to testing and it's still the same.

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Re: Adafruit FONA 808 Shield GPS Problem

by adafruit_support_mike on Fri Mar 08, 2019 1:18 am

In that case, the FONA's GPS module may have been damaged.

When did you get the FONA Shield?

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Re: Adafruit FONA 808 Shield GPS Problem

by nunosilvarocha on Fri Mar 08, 2019 6:14 am

I got the shild on 08/2016.
It was little used (about 20 hours), was always well treated and was always well conditioned.

How can I solve my problem?

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Re: Adafruit FONA 808 Shield GPS Problem

by adafruit_support_mike on Sat Mar 09, 2019 12:23 am

I'm afraid that's long past our 30-day return/replace period.

Try using other antennas to see if they happen to work better. You might also try a powered GPS antenna to see if that works. You'll need to close the solder jumper next to the uFL jack for the antenna so power reaches the antenna, but that's easy and reversible.

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Re: Adafruit FONA 808 Shield GPS Problem

by csutakrichard on Tue Aug 13, 2019 9:44 am

Dear Mike,
I don't want to open a new topic since my question is connected to this one. Earlier you said
You'll need to close the solder jumper next to the uFL jack for the antenna so power reaches the antenna, but that's easy and reversible.
.

I'm not so experienced but enthusiastic. I want to use an active gps antenna. If i'm right I have to solder (red line) these things:
adafruit_products_Fona_America_quarter_800_solder.jpg
adafruit_products_Fona_America_quarter_800_solder.jpg (217.68 KiB) Viewed 38 times

Am I right?

My Fona808 seems a little bit different in the back:
20190813-152128-2.jpg
20190813-152128-2.jpg (110.76 KiB) Viewed 38 times


Picture are avaliable in these links too:
https://ibb.co/xGr1gHd
https://ibb.co/1J9Wk2P

Can you help me?
Thank you,
Richard

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Re: Adafruit FONA 808 Shield GPS Problem

by adafruit_support_mike on Tue Aug 13, 2019 9:00 pm

No, the jumper is on the front of the FONA, right next to the antenna jack:

3147-04.jpg
3147-04.jpg (81.23 KiB) Viewed 22 times

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Re: Adafruit FONA 808 Shield GPS Problem

by csutakrichard on Wed Aug 14, 2019 8:44 am

Thank you very much, I'll try solder it.
Richard

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