[cbvinh]

Usually, when I get into the office, I see T-Mobile service go to AT&T due to poor cell reception. Today, it was on Verizon Wireless for a brief moment. How did that even happen?

[raino]

LTE roaming?

[cbvinh]

LTE roaming?

When I enter the building, the phone goes to "Emergency calls only". It said that when it showed Verizon Wireless today. It didn't last long before it went to AT&T.

[raino]

When I enter the building, the phone goes to "Emergency calls only". It said that when it showed Verizon Wireless today.

Actually that makes a lot of sense. There's no voice roaming because Verizon's CDMA plus different bands, but they do share that LTE band 4--which is what you were roaming on.

[gariac]

If you put the radio into scan mode, you will see Verizon as an option, obviously only for SOS. It has been my experience that when you select Verizon and you get a SOS service, you are actually hooked up to AT$T.

OK, scratch that. I connected to 311 480, which is Verizon.

Also interesting is MetroPCS LTE no longer shows up.

Posted via CB10

[raino]

Also interesting is MetroPCS LTE no longer shows up.

I would think everything was absorbed into TMO, so it would be TMO LTE now?

[gariac]

I would think everything was absorbed into TMO, so it would be TMO LTE now?

Most likely.

Was there a separate MetroPCS system, or was it just some trick to make it look like two systems?

Posted via CB10

[modifier]

Was there a separate MetroPCS system, or was it just some trick to make it look like two systems?

Not sure how you'd trick something like that. Older SIMs might still display the old name if an MNC name gets changed. But, that's not a trick -- just an old database.

Looks like 311-660 was their tower code: https://en.wikipedia.org/wiki/Mobile_country_code

[CB10 / Q10]

[gariac]

Not sure how you'd trick something like that. Older SIMs might still display the old name if an MNC name gets changed. But, that's not a trick -- just an old database.

Looks like 311-660 was their tower code: https://en.wikipedia.org/wiki/Mobile_country_code

[CB10 / Q10]

Back in the day, we had a monthly ham swap meet and a tech from Metro was a regular vendor. I'm kicking myself for not getting his email. I did buy old gear he pulled from shacks that metro bought.

Posted via CB10

[raino]

Was there a separate MetroPCS system, or was it just some trick to make it look like two systems?

Metro at one point did have their own CDMA and LTE networks. The CDMA was fully decommissioned just last month.

[lactose]

So a GSM phone has 911 access from a CDMA network ? One area I visit (behind a big hill) seems to have no TMO or ATT service yet the Emergency call icon is there.

[raino]

So a GSM phone has 911 access from a CDMA network ?

No, I don't think so, but the other way around may work because nowadays most CDMA phones come with at least GSM bands, if not UMTS as well.There's no hardware in an all-GSM phone to get it on the CDMA network.

One area I visit (behind a big hill) seems to have no TMO or ATT service yet the Emergency call icon is there.

Then there has to be some tower it's connecting to. Maybe not even AT&T or TMO, but a regional GSM carrier perhaps.

[gariac]

No, I don't think so, but the other way around may work because nowadays most CDMA phones come with at least GSM bands, if not UMTS as well.There's no hardware in an all-GSM phone to get it on the CDMA network.



Then there has to be some tower it's connecting to. Maybe not even AT&T or TMO, but a regional GSM carrier perhaps.

One really annoying bug I've found on all my BlackBerry phones if that the phone sees a GSM 2g tower that exceeds the 35km hard limit, it shows up as SOS. I have no clue if you can actually call 911 on such a set up. While the phone shows SOS, I've been able to determine the tower is Tmo using the engineering screen.

This only happens when I'm camped at high altitude. The nearest Tmo tower is around 100 miles away. With a clear shot to the tower and a relatively quiet RF surrounding, sniffing the long distance tower isn't all that hard, but of course it will never connect due to 2g timing constraints.

In the analog days, you could make scratchy calls from locations over 100 miles.

Posted via CB10

[raino]

One really annoying bug I've found on all my BlackBerry phones if that the phone sees a GSM 2g tower that exceeds the 35km hard limit, it shows up as SOS. I have no clue if you can actually call 911 on such a set up.

Supposing the call goes through--how accurate is the location/triangulation information going to be?

[gariac]

Supposing the call goes through--how accurate is the location/triangulation information going to be?

With one tower, no location at all. Maybe a radius. But I don't think the phone call will work since it exceeds the 2g TDMA timing spec.

The phone software should really just report no signal even though technically it can see a tower.

Posted via CB10

[modifier]

LTE roaming is common with modern handsets. What's frustrating are the areas where everyone has coverage except T-Mobile and there's no roaming contract in place with any of them.

Classic.



[CB10 / Classic]

[raino]

Attachment 361502

Didn't come through.

Are there actual LTE roaming agreements in place now or are the devices just latching on to a network they have bands for?

[modifier]

Didn't come through.

Are there actual LTE roaming agreements in place now or are the devices just latching on to a network they have bands for?

It works on my Q10 and Classic but shows as a link on the website. Click the image to view it.

No clue on the actual roaming agreements. My point was more that they're nonexistent despite the handset being able to see everyone's antenna -- well, everyone except T-Mo in this case. Without a roaming agreement there's no way to latch onto a tower so the latter part of your question is a cart/horse issue. The horse has to go first.

[CB10 / Q10]

[raino]

Without a roaming agreement there's no way to latch onto a tower so the latter part of your question is a cart/horse issue. The horse has to go first.

Got it. Makes sense.

It works on my Q10 and Classic but shows as a link on the website. Click the image to view it.

I get an invalid attachment error. Oh well.

[modifier]

I get an invalid attachment error. Oh well.

Try now. I attached it via the website instead.

[raino]

Try now. I attached it via the website instead.

Works now.

Very interesting to see Sprint on the list. Unlike Verizon and AT&T, Sprint don't share bands with TMO. But Sprint does have b25 and b26 networks, and these two bands are supersets of b2 and b5, respectively--bands which are present in the Q10 -5. Any idea how they showed up, though? I would have expected a Sprint phone to pick up b5 and b2 networks (subsets,) but not the other way around, as it happened here (supersets.)

[gariac]

Try now. I attached it via the website instead.

Got it.

The only roaming carrier I have run into is USA Commnet. They have 4g voice and data last time I used it. But I see no reason why you can't roam on LTE with a contract in place.


Posted via CB10

[modifier]

Any idea how they showed up, though? I would have expected a Sprint phone to pick up b5 and b2 networks (subsets,) but not the other way around, as it happened here (supersets.)

It was on a Classic -4. I didn't have my Q10 -5 with me at the time. It could have picked up 2/5/25. I didn't have time to check signals.

But I see no reason why you can't roam on LTE with a contract in place.

Agreed. The lack of roaming contracts in this area is the problem.

[CB10 / Q10]

[raino]

It was on a Classic -4. I didn't have my Q10 -5 with me at the time. It could have picked up 2/5/25. I didn't have time to check signals.

That makes a lot of sense then. The Classic -4 has band 25.