Martin_NZ:

I was at work and set it up this afternoon. Left work. Drove home, connected to my home wifi. Made some dinner then got a call on my home phone from mum to say she tried to ring on my mobile.

Sure enough toggled flight mode on then off and two missed calls notifications and a txtmessage came through

Of interest is a message on the notification shade which I haven't seen before "SIM not allowed for voice" and the same "Emergency calls only" where it usually says Vodafone NZ

@Montana308 bars mean nothing you need to know the RSSI difference between the 2 handsets and what band the handset is actually camped on

As previously stated, this would seem unrelated to the issue this thread is about, and appears to quite likely be a signal strength issue. You previously mentioned you were rural.

To find the signal strength on the Galaxy you would go to Settings, About Phone, Status, SIM Card Status. The signal strength will show as a number like -70dBm 60 asu

The less negative the dBm number is the better the signal.  The higher the ASU the better

Not sure how you get similar details on the OPPO. 

As a rough guide

-50 to -79 dBm, then it's generally considered great signal (4 to 5 bars). -80 to -89 dBm, then it's generally considered good signal (3 to 4 bars). -90 to -99 dBm, then it's generally considered average signal (2 to 3 bars). -100 to -109 dBm, then it's generally considered poor signal (1 to 2 bars).

Yes -108 is getting pretty low. Remember dBm is a logarithmic scale. For each 3dBm decrease you are roughly halving the signal strength.

https://en.wikipedia.org/wiki/DBm

I cannot be certain that could be the cause of your issues. Your only real option may be to nag your service provider or go stand on your roof.

@Montana308 -108 is not to bad for 4G but not the best for 3G

Just remember if you are doing nothing on the handset then this is just camping on a cell and as soon as you do something it might hand to another stronger band

So handset could be camped on 1800Mhz 4G -108 and then can quickly change to 700Mhz 4G (Guess -85 or -90)

Open the field tester on your handset and you can see how fast it changes between bands when required

I'm glad I found this thread because I thought it was just affecting my phone.  I am on Vodafone and last year I have had numerous times when I would be in the middle of a phone call and it would hang up/disconnect while I am in a call, then I would check my phone and there would be a message in the notifications that reads "Not registered on network".  A phone reboot is what I've been doing to fix it.  I get the usual response from Samsung about checking if the sim card is inserted properly (if this was the case then why would a reboot fix the issue?) and trying to reset the phone back to defaults.

Hi all, I just thought I would give you all an update on this.  I logged my fault with Samsung (the message my phone kept getting was 'Not registered on network'), after trying several things (resetting to defaults, etc) I eventually sent the phone into the service center.  The service center checked over the phone for a few hours and ran some tests, the issue (which is always intermittent) never occurred during the few hours they tested it but they did confirm the 'Not registered on network' issue had happened to me over 10 times over the last few months.  They then gave Samsung their recommendation (which I'm assuming was a network fault/issue) and Samsung eventually declined my refund/replacement request.  I requested a case manager review this decision and now the case manager has also said they won't be issuing me a refund or replacement because they suspect it is a network fault, not a Samsung phone fault.  Even after informing them about this forum/discussion they still refuse to acknowledge the fault.

I have decided to use the Samsung/Ingram xchangemobile service and get some money from my phone, rather than selling it through Trademe and have some poor sucker stuck with a faulty phone.

Edit: This issue happened to me using both Vodafone and Spark networks, so there is no way it can possibly be a sim card or 'network' fault.