On 16/04/18 12:12, Criggie wrote:
After 2Degrees discontinued 2G coverage my android phone became unable
to detect their 3G network within range of my home wifi. I somehow fixed
this for a couple of days last week but then went to Christchurch and it
stopped working again.

Do you guys have a clue what's going on? I can't find anything about
this on DDG or Google.

Pure coincidence.  Your android phone won't be 2G only, it might have been
able to talk on those bands, but it will support higher.

I would recommend remaining a little bit more open-minded for a little bit longer, rather than dismissing certain hypotheses too early. Why would I say that? Two reasons:

1. Well, yes, WiFi is not related to 2G or 3G, except... they are not _meant_ to be related. But, and this is important, radio comms isn't always exactly what it is meant to be everywhere. And radio comms can be operating along a sliding range of marginality that can sometimes expose causal connections that are neither usually expected, nor exist by design.

2. I have seen extensive statistics of other supposedly unrelated radio comms things going wrong since the 2degrees change, and a causal connection has been demonstrated conclusively (WiFi was not part of that story, though). Sorry, I am not at liberty to share further details, and I am certainly not suggesting that anyone has done anything wrong, in particular I am not aware that 2degrees have done anything wrong.

Wireless ethernet uses a different radio in the device, they're unrelated.

Yes, well, that's the theory. But in principle it is quite possible that spurious emissions from a nearby WiFi device could jam a weak cellular signal in a different band. And it is worthwhile mentioning that this could happen even if all devices and all parties are fully compliant with all relevant regulations. Whether it happens in practice depends on the marginality of operating conditions, and also on the extent to which everything just meets, or exceeds regulatory limits regarding spurious emissions.

Reminds me of the "you changed the server and now my car won't start"
users, which are sadly all-too-real.

Sorry, no - this case here is different: we are talking about radio comms, and interference is very well known in principle. And yes, I do appreciate that it usually shouldn't be happening between these bands. But again, you may be able to find a configuration where it actually does. Also, interference from spurious emissions is only one possible causation. There are other ways of making cellular radio systems fail, though, that may be relevant in this case.

Things to try:

A good list, and a couple to add:

* Move around in the neighbourhood (away from home) to see whether behaviour 
changes locally.
* Get one of these on-line unofficial maps of 2degrees, Spark and Vodafone base stations, and test at a location close to your provider, and then at a location close to the other providers, but further away from yours. That may help to narrow it down. (This is to some extent looking into possible 2G-3G coexistence issues.)


Kind regards,

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