SIM900 - No registration to network

[djekk]

ok
I will do next thing

Ill send simple AT command every hour , may be this wake up it

[Knowtra]

Hello,
My shield is working now !
The antenna connector was not soldered properly. I made some soldering work on my shield and it works now ! I am registered to the network and I can send/receive some SMS.
Here is the problem !
See the picture included in this message.

Hi,

Hotkebab99, thank you so much for insightful post on how to get the sim900 shield working. I must have spent month trying to get it to connect and register to the network. It has been very frustrating. The only way I could get it to reliably register was to test it while sitting in the car 200m from the mobile mast. The u-fl socket on my sim900 board was soldered back to front and the antenna side connector wasn't actually soldered on to the u-fl socket at all. For anyone else that needs to make this correction, getting the u-fl socket off the board can be tricky. I wrapped a piece of stripped single core wire around the u-fl socket and soldered it on to the points of contact between the socket and the board. I could then get the soldering iron heat to distribute to all contact points. Unfortunately the socket did get a bit messy in the process so I found it easier to just cut the u-fl plug off the antenna wire. I then soldered the sheath to the u-fl socket ground near the 5v barrel plug and the central antenna wire to the sim900 side of where the u-fl socket was.

[pepke]

Finally solved!

I have spent months…. several times give up ….after long time, today looked again on the forum and managed to fix the problem related to wrong socket position - thanks to forum discussion.

With wrongly solder uf-l socket I was hardly login to 800/1800 network, having signal strength AT+CSQ at +CSQ: 4,0 level

AT+CSQ
+CSQ: 4,0

Sometimes it stay logged for a while, sometimes for couple of hours – now I know it depended on network signal strength and shield location in regards to BTS.

After socket re-solder signal immediately it jumped to:
AT+CSQ
+CSQ: 22,0

Easy to test – pick pieces of wire and provide temporary connection between RF antenna connector and RF pin on PCB while shield is power ON equipped with SIM and AT commands are available. Instantly run AT+CSQ command and see how signal strength changes.

If GSM/GPRS shield is working well no need any extra 5V/2A connection.

Shield starts up immediately and after 4-5 sec “NetLight” LED blinks every 3 sec = successfully network login. Also no need main Arduino shield to test GSM/GPRS shield.

I used hot air gun to correct manufacture error. Socket need to be re-soldered - rotated 180 degree.


See attached pictures of wrong uf-l socket position



Geeetech SIM900 network registration problem; Arduino GPRS shield SIM900 network login problem