Signal Strength For T-Mobile SIM Card

tb

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Sep 6, 2018, 1:44:19 PM9/6/18

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My cell phone has two SIMs installed. One from AT&T and the other from
T-Mobile.
I have frequently noticed that when I am in a building (airport,
shopping center, hotel, etc.) my AT&T SIM gets a strong signal while
the T-Mobile one does not get a signal.
How can this be possible? Are SIM cards not all equal in terms of
their technical characteristics?
PS: I have tried swapping the SIM cards in the two slots but the
result is the same...

--
tb

nospam

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Sep 6, 2018, 3:01:51 PM9/6/18

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In article <xn0lemo3...@reader.albasani.net>, tb

<nos...@example.invalid> wrote:

> My cell phone has two SIMs installed. One from AT&T and the other from
> T-Mobile.
> I have frequently noticed that when I am in a building (airport,
> shopping center, hotel, etc.) my AT&T SIM gets a strong signal while
> the T-Mobile one does not get a signal.
> How can this be possible?

at&t may have better coverage in that location and/or your phone may
not have all of the bands t-mobile uses, especially at those locations.

> Are SIM cards not all equal in terms of
> their technical characteristics?

no

tb

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Sep 6, 2018, 3:37:24 PM9/6/18

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This happened in places like Memphis or San Francisco, so I imagine
that the coverage there by T-Mobile is as good as the one by AT&T.

How do I find out which bands are used by T-Mobile in these two
locations?

--
tb

nospam

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Sep 6, 2018, 4:49:55 PM9/6/18

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In article <xn0lemr3...@reader.albasani.net>, tb

<nos...@example.invalid> wrote:

> > > My cell phone has two SIMs installed. One from AT&T and the other
> > > from T-Mobile.
> > > I have frequently noticed that when I am in a building (airport,
> > > shopping center, hotel, etc.) my AT&T SIM gets a strong signal while
> > > the T-Mobile one does not get a signal.
> > > How can this be possible?
> >
> > at&t may have better coverage in that location and/or your phone may
> > not have all of the bands t-mobile uses, especially at those
> > locations.
> >
> > > Are SIM cards not all equal in terms of
> > > their technical characteristics?
> >
> > no
>
> This happened in places like Memphis or San Francisco, so I imagine
> that the coverage there by T-Mobile is as good as the one by AT&T.

as good or better, but that's overall. you could be in a dead spot. no
carrier has coverage everywhere.

<https://opensignal.com/blog/2018/03/15/the-4g-battle-continues-between-
t-mobile-and-verizon/>

> How do I find out which bands are used by T-Mobile in these two
> locations?

<https://www.phonearena.com/news/Cheat-sheet-which-4G-LTE-bands-do-AT-T-
Verizon-T-Mobile-and-Sprint-use-in-the-USA_id77933>

check the specs for your phone which bands it has.

(PeteCresswell)

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Sep 7, 2018, 11:10:13 AM9/7/18

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Per tb:

>My cell phone has two SIMs installed. One from AT&T and the other from
>T-Mobile.
>I have frequently noticed that when I am in a building (airport,
>shopping center, hotel, etc.) my AT&T SIM gets a strong signal while
>the T-Mobile one does not get a signal.
>How can this be possible? Are SIM cards not all equal in terms of
>their technical characteristics?

I have no clue, but noticed the same thing with two Samsung Notes
side-by-side: one connected to Sprint and the other connected to tMobile.

And, to add to the confusion, I have put my phone connected to tMobile Legacy
Prepaid next to another phone connected to tMobile Monthly and seen a
sustained difference - and also multiple tower handoffs on the Prepaid vs no
handoffs on the Monthly.
--
Pete Cresswell

tb

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Sep 11, 2018, 12:37:04 PM9/11/18

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I have a BLU Studio 5.0 II which, according to GSMArena.com, has the
following specs:

Technology GSM / HSPA
2G bands GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2
3G bands HSDPA 850 / 1900 / 1700 - D532u
HSDPA 900 / 1900 / 2100 - D532v
Speed HSPA 21.1/5.76 Mbps
GPRS Class 12
EDGE Class 12

I see that T-Mobile uses the GSM/HSPA+ network; 3G frequencies are
1900, 1700/2100; 3G bands 2, 4.

It would appear that the phone has some but not all of the 2G/3G bands
used by T-Mobile. Is that the cause of the problem that I have?

Why does the AT&T SIM card get a strong signal when I am away from a
window but not the T-Mobile SIM card?

--
tb

MK

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Sep 12, 2019, 1:27:41 AM9/12/19

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"tb" <nos...@example.invalid> wrote in message
news:xn0lemo3...@reader.albasani.net...

I carried two tmobile phones, one for business, and one personal. One phone
was an AT&T phone, converted to tmobile. During an alarm, I noticed that I
did not get the warning on the original tmobile, and was told the hospital
blocks anything but at&t.

nospam

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Sep 12, 2019, 9:57:22 AM9/12/19

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In article <ch9ahe....@news.alt.net>, MK <M...@invalid.com> wrote:

> I carried two tmobile phones, one for business, and one personal. One phone
> was an AT&T phone, converted to tmobile. During an alarm, I noticed that I
> did not get the warning on the original tmobile, and was told the hospital
> blocks anything but at&t.

whoever told you that is an idiot.

since you received a warning on one phone but not the other, it's
obviously not blocked, plus there is no benefit to blocking only one
carrier and allowing the others.

it's possible that reception inside the building is not that good and
affects t-mobile more than the others, but that's *very* different than
intentionally being blocked.

MK

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Sep 13, 2019, 12:34:49 AM9/13/19

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"Anthony R. Gold" <not-fo...@ahjg.co.uk> wrote in message
news:jl5kneh4rr6e6nsfa...@4ax.com...

> Blocking cell signals is a violation of federal law - The Communications
> Act
> 1934 (as amended). https://www.fcc.gov/general/jammer-enforcement

Thank you for that website. I don't have that business anymore, but I said
"this should be illegal", not knowing that it already was. Too bad I did
not know at the time, or I would have reported it.

Allodoxaphobia

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Sep 13, 2019, 9:34:25 AM9/13/19

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And, the environment inside a hospital can be VERY RF "NOISY"!
All that medical equipment is certified for use and safety -- not
so much for radio interference.

Elmo P. Shagnasty

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Oct 27, 2019, 10:49:56 AM10/27/19

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They don't actively block anything.

However, they probably have a contract with AT&T to have AT&T cell
sites inside the hospital, specifically to address the fact that
hospitals are not great places for cell signals.

So they were probably saying "we specifically enable AT&T inside our
infrastructure," not "we block anything but AT&T".

That all being said, my local hospital has superb customer wifi--and
while my T-Mobile phone gets zero cell service inside, it works great
with their wifi. It's no different than having good T-Mo service out
on the street.

And that's why T-Mo went all in with wifi calling years ago.