Which app do you use to scan/debug GSM/CDMA cellular tower s

[The Real Bev]

On 02/17/2017 04:01 PM, Jeff Liebermann wrote:

On Fri, 17 Feb 2017 14:27:15 -0800, The Real Bev
bashley101@gmail.com> wrote:

On 02/16/2017 07:21 PM, Jeff Liebermann wrote:
Marketing research: How much would pay for such a device?

Nothing. I've been hooked on 'free' for a long time, especially since
the paid version is rarely significantly better than the free version.

Oh well. It's rather difficult to build a company based on a free
product (unless one sells advertising).

Fine with me. Just how much can a person make from app-advertising?

Once the DF method is
established by me or someone else, I'm sure it will be cloned, copied,
or distributed as "open hardware". That's why I haven't done anything
with the idea for several decades. Enjoy free while it lasts. I'm
thinking more of a Kickstarter, Indiegogo, or other crowdfunding
project.

And yet people do it...

--
Cheers, Bev
"My dad used to say: Laugh, and the whole world laughs with you.
Cry, and I'll give you something to cry about you little
bastard." -Jeff Goldblum

 

[nospam]

In article <o8ad3c$8ru$1@dont-email.me>, The Real Bev
<bashley101@gmail.com> wrote:

Marketing research: How much would pay for such a device?

Nothing. I've been hooked on 'free' for a long time, especially since
the paid version is rarely significantly better than the free version.

Oh well. It's rather difficult to build a company based on a free
product (unless one sells advertising).

Fine with me. Just how much can a person make from app-advertising?

a lot.

<http://www.adweek.com/digital/googles-ad-revenue-hits-19-billion-even-m
obile-continues-pose-challenges-172722/>
During the second quarter of 2016, Alphabet's revenue hit $21.5
billion, a 21 percent year-over-year increase. Of that revenue, $19.1
billion came from Google's advertising business, up from $16 billion
a year ago.

 

[nospam]

In article <o8adfn$1c5u$5@gioia.aioe.org>, Stijn De Jong
<stijndekonlng@nlnet.nl> wrote:

In the basement (cellspot is in the garage) I have -78dB currently. If I
go into the garage it's about -60dB-65dB, IIRC.

That's absolutely astoundingly high cellular signal strength (RSSI).
All the articles put the range at -50 to -110 or -120dBm.

-50 is the maximum possible, and below -120 there is no signal.

Are you getting that from your T-Mobile micro tower?
How do you know? (Because that's the entire reason for this thread.)

my iPhone displays the dB in the upper left corner. I's at -78 again.

I knew how you got the decibel RSSI (received signal strength indication),
but the question was how do you know which "tower" you're getting your
current signal from.

based on what you've written, no, you did not know that.

As far as anyone can tell, it's impossible to get the cell id tower from
the phone on an iOS device,

wrong.

so you have to use an Android device to figure
that out.

maybe you do, but the rest of the world doesn't, assuming they even
care what the tower id is.

everyone *other* than cellular engineers don't care, and the cellular
engineers have *far* more sophisticated equipment to find out than by
using an android or ios phone.

 

[Lewis]

In message <o8adfn$1c5u$5@gioia.aioe.org> Stijn De Jong <stijndekonlng@nlnet.nl> wrote:

I knew how you got the decibel RSSI (received signal strength indication),
but the question was how do you know which "tower" you're getting your
current signal from.

I haven never cared to check. If I unplug the t-mbile cellspot, my
signal in the basement drops significantly and I lose calls.

I don't care which tower or micro tower I am connected to.

So just having a decibel reading doesn't tell me *which* tower I'm
connected to (since there are at least three or more to choose from).

So? Who cares?

The good news is that my decibel readings are now in the -50dBm to -60dBm
range (instead of the minus 90 to minus 100 decibel range as they were
before I hooked up the micro towers!).

That's all that matters.

--
The real American folksong is a rag -- a mental jag A rhythmic tone for
the chronic blues

 

[Jeff Liebermann]

On Sat, 18 Feb 2017 13:09:46 -0800, The Real Bev
<bashley101@gmail.com> wrote:

On 02/17/2017 04:01 PM, Jeff Liebermann wrote:
On Fri, 17 Feb 2017 14:27:15 -0800, The Real Bev
bashley101@gmail.com> wrote:

Just how much can a person make from app-advertising?

You keep thinking of an Android App. This is a hardware based
direction finder that has a built in computah to do the number
crunching. No smartphone or Android gizmo involved. Therefore, I
won't be selling apps on the Play Store.

"Google Play app revenue up 82% in Q4 2016, 60% growth for the App
Store"
<http://www.gsmarena.com/google_play_app_revenue_up_82_in_q4_2016_60_growth_for_the_app_store-news-22759.php>
Google Play store collected $3.3Billion in revenue. Last year, the
split was 70% Google and 30% developer. Therefore the developers
collected about:
$3.3 billion / 0.7 * 0.3 = $1.4 billion
This year, the split is 85% Google and 15% developer, which indicates
that Google is getting greedy, developers were making to much money,
or both.

Blundering onward, the Play store has 2.6 million apps available.
About half are free, so that's 1.3 million apps. Average revenue per
app would be:
$1.4 billion revenue / 1.3 million apps = $1,100 revenue/app/year
Not enough to support product development.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Sun, 19 Feb 2017 02:07:16 +0000 (UTC), Stijn De Jong
<stijndekonlng@nlnet.nl> wrote:

On Thu, 16 Feb 2017 01:52:24 +0000 (UTC), Stijn De Jong wrote:

Q: Which app do you use on iOS or Android to figure out all the cellular
towers and signal strengths of the cellular signal (CDMA or GSM) in your
area?

This is a question and initial observation for Jeff Liebermann.

Why me?

Does a cellular booster propagate the original cell tower identification?
(Or does the boosted signal have its own cell tower identification number?)

By "booster" are you referring to a bi-directional amplifier like
products from Wilson:
<http://www.wilsonpro.com/residential-cell-phone-signal-boosters>
or Wi-Ex (zBoost)?
<https://www.signalboosters.com/zboost-signal-boosters>
I so, they repeat exactly the original signals both incoming and
outgoing. What you hear is the tower ID. The device does not
generate any new data or belch a new tower ID.

However, if you're referring to a Femtocell or similar internet
connected microcellular device, the answer is yes, they do have their
own unique ID.

My initial assumption (which needs to be tested) is two fold:
a. It seems the router-connected micro tower has its own unique cell id.

Yep.

>b. It seems the booster may simply propagate the "real" cell tower cell id.

Yep.

>Does that make sense?

Yep.

How far away do you think the strongest (or nearest) T-mobile cell
tower is located from your test location? Any possibility that one of
your neighbors might have a T-mobile microcell box that you're
hearing? I'm suspicious of the rather strong tower signal.

Back of the envelope calculation:
+27dBm Estimated transmit power from the cell site
+10dB My guess of the panel antenna gain
-53dBm Receive signal level from your test.

Path loss = 27 + 10 + 53 = 90dB
Calculating the distance where the path loss would be -90dB at 700MHz:
<http://www.proxim.com/products/knowledge-center/calculations/calculations-free-space-loss>
is about 0.7 miles or about 4,000 ft. The cell tower would need to be
rather close to your location for that to work. Like I said, I'm
suspicious of what you're measuring.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[tlvp]

On Sat, 18 Feb 2017 22:52:40 -0500, nospam wrote:

> the average isn't what matters. a quality app can be *very* profitable.

So can a lottery ticket, and it's easier to develop. Cheers, -- tlvp
--
Avant de repondre, jeter la poubelle, SVP.

 

[Jeff Liebermann]

On Sat, 18 Feb 2017 21:14:27 +0000 (UTC), Stijn De Jong
<stijndekonlng@nlnet.nl> wrote:

On Fri, 17 Feb 2017 17:12:20 -0800, Jeff Liebermann wrote:

As for the tower antenna patterns being direction, it's a matter of
what you consider directional. In the typical 3 sided tower
configuration, the sector antennas have a horizontal beamwidth of
about 60 degrees. The tower can and does indicate which sector is
being used, but that has a granularity of 120 degrees, which is hardly
accurate enough to determine anyones position.

Hi Jeff,

This article describes the three 120-degree sectors:
Alpha is the North FACING vertical antenna on the cell tower
Beta is the Southeast FACING vertical antenna on the cell tower
Gamma is the Southwest FACING vertical antenna on the cell tower
http://www.evdoforums.com/thread15374.html

I dialed #878# and got:
"Welcome to Verizon Wireless. Your call cannot be completed as
dialed..."

There is a way to tell which sector antenna you're connected to from the
cell id. Also, the newer Android APIs now seem to expose the frequency
bands:
http://people.csail.mit.edu/bkph/cellular_repeater_inside.shtml

Nice article. I think there is a way of extracting the sector but I
don't know what it might be and am too lazy to work it out right now.
My leaky roof and irate customers come first.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[nospam]

In article <514iachpen7vqkn4thndi5i91ls58rvh96@4ax.com>, Jeff
Liebermann <jeffl@cruzio.com> wrote:

Blundering onward, the Play store has 2.6 million apps available.
About half are free, so that's 1.3 million apps. Average revenue per
app would be:
$1.4 billion revenue / 1.3 million apps = $1,100 revenue/app/year
Not enough to support product development.

the average isn't what matters. a quality app can be *very* profitable.

 

[Jeff Liebermann]

On Sat, 18 Feb 2017 21:31:53 +0000 (UTC), Stijn De Jong
<stijndekonlng@nlnet.nl> wrote:

On Fri, 17 Feb 2017 18:43:40 -0800, Jeff Liebermann wrote:

My GSM phones show a valid lat-long. My CDMA phones show no data.

I'm still trying to figure this stuff out, but I noticed this MIT app
(CellTracker) "attempts" to show both what the GPS says and the latitude
and longitude for Verizon.
http://people.csail.mit.edu/bkph/images/Screenshot_2013-04-16-15-29-00

CellTracker:
http://people.csail.mit.edu/bkph/CellTracker

Nice app, but it does NOT show the lat-long of the local Verizon cell
site. See attached screen grab:
<http://802.11junk.com/jeffl/crud/CellTracker.jpg>
Celltracker for Android 5.0 on a Moto G v1 phone running Android 5.1.
Note from the screengrab that the GPS is on and running. The "WIFI
Lat-Long" is the location of my house, not the local cell site. I
don't know where my Lat-Long came from (probably Google Maps
database).

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Stijn De Jong]

On Sat, 18 Feb 2017 16:29:17 -0500, nospam wrote:

As far as anyone can tell, it's impossible to get the cell id tower from
the phone on an iOS device,

wrong.

Certainly, technically competetent iOS users have tried over the years...
http://stackoverflow.com/questions/13399659/get-cellid-mcc-mnc-lac-and-network-in-ios-5-1
https://blog.hqcodeshop.fi/archives/253-iPhone-cell-Field-Test-mode.html
http://www.ahmadrifky.com/ict-stuff/iphone-measuring-your-carrier-operator-signalbandwidth-license-and-location-in-just-a-split-seconds
https://discussions.apple.com/thread/4995211?start=0&tstart=0

Even iOS app developers have tried...
https://forums.developer.apple.com/thread/21018
https://sourceforge.net/p/dpfdelphiios/tickets/232/

What do you know that they don't know?

 

[Stijn De Jong]

On Sun, 19 Feb 2017 02:31:01 -0000 (UTC), Lewis wrote:

I haven never cared to check. If I unplug the t-mbile cellspot, my
signal in the basement drops significantly and I lose calls.

You are perfectly correct in that simply unplugging a single micro tower
will likely cause the signal strength to "fluctuate".

The signal strength, however, can easily be similar since it fluctuates
normally anyway, e.g., all my neighbors also have micro towers (basically
everyone has them out here).

Worse, when I unplug my booster, it takes about fifteen minutes for the
cell signal to set itself up, and, even then, it seems that the booster
simply "passes through" the cell tower ID it is boosting (I need to
research that further though). So, unplugging it in order to figure out if
I'm connected to it, is problematic.

However far worse than that, when I unplug my router-connected micro tower,
it takes multiple hours for the thing to set itself up. T-Mobile says that
it can take up to two hours, but I found out that it takes even longer than
that, as last night I literally fell asleep before the thing started taking
on my cell phone.

I had to look at the log file in the morning.

BTW, for Jeff Liebermann, I found another app that logs the connections,
so, that's three apps which log all the towers connected to, only one of
which (NetMonitor) allows you to modify how that log appears (which is a
nice feature) to the user in real time.

Some logs save as text, others as CSV, so I'll write up separately for you
and others to benefit, which apps were best for logging the cell tower IDs.

> I don't care which tower or micro tower I am connected to.

Most people don't care which tower they're connected to; however, if they
were debugging their connection, they'd start to care.

In my case, T-Mobile only allows one device, which is what I found out when
the second device tried to use the same 911 address as the first device,
so, they "may" ask for one of the devices back (I had asked for a third
device, but that is currently out of the question).

If I have to give one device back, it is helpful to know which device
worked best, and for that, waiting two or more hours between tests is crazy
when I can just look at the unique cell id of the router-based device to
tell if that's what I'm connecting to.

So just having a decibel reading doesn't tell me *which* tower I'm
connected to (since there are at least three or more to choose from).

So? Who cares?

If my good signal strength is actually due to my neighbor's micro tower,
how would I know?

If I have to send back one device to T-Mobile, which device would I send
back?

The good news is that my decibel readings are now in the -50dBm to -60dBm
range (instead of the minus 90 to minus 100 decibel range as they were
before I hooked up the micro towers!).

That's all that matters.

Not really. If T-Mobile wants one of their devices back, which one do I
give them?

 

[Stijn De Jong]

On Sat, 18 Feb 2017 20:14:28 -0800, Jeff Liebermann wrote:

CellTracker:
http://people.csail.mit.edu/bkph/CellTracker

Nice app, but it does NOT show the lat-long of the local Verizon cell
site. See attached screen grab:
http://802.11junk.com/jeffl/crud/CellTracker.jpg

Thanks Jeff for installing that app, which isn't on F-Droid or Google Play,
so we both took a risk in doing so (I'm not sure how to ameliorate that
risk, but that's the topic of a different Android thread).

I've only used that MIT CellTracker for a day, so take everything below
with a grain of salt but look at this screenshot first:
http://i.cubeupload.com/407ihh.jpg

That MIT CellTracker app does appear to list two GPS locations:
1. Where you are
2. Where the connected tower is

That first GPS location it probably gets from our GPS receivers, while the
second GPS (which it calls "NMAP") location is likely from a lookup
database.

Note from the screengrab that the GPS is on and running. The "WIFI
Lat-Long" is the location of my house, not the local cell site. I
don't know where my Lat-Long came from (probably Google Maps
database).

Sometimes it says "NMAP NOT FOUND" as your photo shows, but other times it
says "NMAP" and then the GPS location and height of the tower in meters.

What I don't like about this MIT CellTracker is that it reports signal
strength in ASU and not in Decibels (yes, I know, it can be converted).

However, what I like about this MIT CellTracker non-Google-Play app is I
can see, visually, the documented cell towers bouncing around, even when I
use my signal booster micro tower.

Here's an edited example of what a user might see of that bouncing:
http://i.cubeupload.com/ZHepme.jpg

Celltracker for Android 5.0 on a Moto G v1 phone running Android 5.1.
I'm on Android 4.3 Samsung Galaxy S3, T-Mobile, in the boonies near you.

After two days, I've whittled down the good freeware to 4 applications:
http://i.cubeupload.com/OwXjWZ.jpg

 

[Stijn De Jong]

On Sun, 19 Feb 2017 09:41:15 -0800, Jeff Liebermann wrote:

It's MMAP, not NMAP. MMAP (Mobile Message Access Protocol) is a
protocol for sending SMS messages over the internet:
http://www.phonescoop.com/glossary/term.php?gid=269
https://yidonghan.wordpress.com/2008/01/02/mobile-message-access-protocolmmap-version-1-0/
http://xml.coverpages.org/SMS-MMAPv12a.pdf

Oooops. My eyes! They suck! That's the main reason I wish the iOS iPads
could do some of this stuff. I can't *see* the little screen on my S3!

Thanks. I appreciate the correction.

Another thing I appreciate is that you researched the NetMonitor app, which
does logs *better* than all the other apps did!
a. NetMonitor logs are the most customizable
http://i.cubeupload.com/ZAcsok.jpg
b. GSM Signal Monitoring has great csv logs
http://i.cubeupload.com/69bgcS.jpg
b. CellTracker logs manually (by pressing the blue arrows)
http://i.cubeupload.com/FhY2UX.jpg

They all do logs differently though; but what I like about NetMonitor logs
is that you can *change* how the site appears in the real-time log.

So, for example, if a site shows up in NetMonitor originally as:
12345 54321 6789
California, USA, Santa Cruz, CA 95060

You can change that to something that makes sense to you, such as:
12345 54321 6789
1555 Soquel Dr. tower, north facing alpha sector

Or even just the one line:
1555 Soquel Dr. tower, north facing alpha sector

And, in all subsequent logs (real time or post mortem), it will show up
that way for you (or so it seems) with an asterisk in front (it seems).

In summary, all three apps listed above do logs differently, but the app
you suggested for logging does them the best because they're just a bunch
of numbers if you can't change them to indicate something more meaningful
to you (such as the sector or the street location) in real time.

 

[Stijn De Jong]

On Sat, 18 Feb 2017 19:48:00 -0800, Jeff Liebermann wrote:

http://www.evdoforums.com/thread15374.html

I dialed #878# and got:
"Welcome to Verizon Wireless. Your call cannot be completed as
dialed..."

I got a similar message, but for T-Mobile (your call cannot be completed as
dialed, or something like that). But I didn't know if it was just T-Mobile
or not.

Thanks for running that test for Verizon.

There is a way to tell which sector antenna you're connected to from the
cell id. Also, the newer Android APIs now seem to expose the frequency
bands:
http://people.csail.mit.edu/bkph/cellular_repeater_inside.shtml

Nice article. I think there is a way of extracting the sector but I
don't know what it might be and am too lazy to work it out right now.
My leaky roof and irate customers come first.

Speaking of leaky roofs, I can't believe the rain we've been having!
I am sick and tired of rain, mudslides, & road closures near the summit!
We're getting a windy storm tomorrow too! (Brace yourself!).

I have completed my initial tests on the Android free apps though.
I know I'm done with the first phase when I've uninstalled all the apps
that irk me.

I'm left with these four, each of which does something nice that the others
don't do as well.
https://i.cubeupload.com/vKLAu8.jpg

While some of these apps do wifi scanning, I keep a separate folder for the
best freeware wifi scanners, as shown below:
https://i.cubeupload.com/Z1qvPZ.jpg

If folks want to save time, you can't go wrong loading just one or more of
those four best freeware apps (in my tests anyway) for cellular debugging.

Network Cell Info Lite, version 3.30:
http://i.cubeupload.com/HoKTav.jpg
http://wilysis.com/networkcellinfo
https://play.google.com/store/apps/details?id=com.wilysis.cellinfolite

Netmonitor, version 1.2.15:
https://i.cubeupload.com/TfDJaS.jpg
https://play.google.com/store/apps/details?id=com.parizene.netmonitor

MIT CellTracker:
http://i.cubeupload.com/ZHepme.jpg
http://people.csail.mit.edu/bkph/CellTracker

GSM Signal Monitoring, version 4.02:
http://i.cubeupload.com/V9O0Gg.jpg
https://play.google.com/store/apps/details?id=com.signalmonitoring.gsmsignalmonitoring

You'll also want this, but I put it in my WiFi folder instead:
WiGle WiFi Wardriving (which also reports cellular towers):
http://i.cubeupload.com/ZPva3O.jpg
https://play.google.com/store/apps/details?id=net.wigle.wigleandroid

Unfortunately, the freeware version of Network Signal Info crashed a lot
so I uninstalled it, but if it works for you, it's also very good.
Network Signal Info, version 3.63.01:
http://i.cubeupload.com/2zK8Ys.jpg
https://play.google.com/store/apps/details?id=de.android.telnet

If you want log files, you are limited to these three, in order:
a. NetMonitor logs are the most customizable
http://i.cubeupload.com/ZAcsok.jpg
b. GSM Signal Monitoring has great csv logs
http://i.cubeupload.com/69bgcS.jpg
b. CellTracker logs manually (by pressing the blue arrows)
http://i.cubeupload.com/FhY2UX.jpg

As always, I hope these detailed summaries and research and tests help
others now, and in the future. Of course, if you have improvements, please
share!

 

[Stijn De Jong]

On Sun, 19 Feb 2017 10:43:16 -0500, nospam wrote:

As far as anyone can tell, it's impossible to get the cell id tower from
the phone on an iOS device,

wrong.

Certainly, technically competetent iOS users have tried over the years...

and have succeeded:

https://ociotec.com/wp-content/uploads/2016/11/proveedor_telefonia.png

https://pbs.twimg.com/media/C29OaIVXAAEPTMG.jpg

I've seen those pictures before since they were in the references I already
cited.

Where is the unique cell ID in those pictures?

There is only one "cell id" and it's simply the number 388, which isn't a
unique cell id in any sense of the word.

What do you know that nobody else on iOS knows?

 

[nospam]

In article <o8cd8h$cep$1@gioia.aioe.org>, Stijn De Jong
<stijndekonlng@nlnet.nl> wrote:

As far as anyone can tell, it's impossible to get the cell id tower from
the phone on an iOS device,

wrong.

Certainly, technically competetent iOS users have tried over the years...

and have succeeded:

<https://ociotec.com/wp-content/uploads/2016/11/proveedor_telefonia.png>

<https://pbs.twimg.com/media/C29OaIVXAAEPTMG.jpg>

 

[nospam]

In article <5ywbkrysutvt$.1a5ko8xbsdqeh.dlg@40tude.net>, tlvp
<mPiOsUcB.EtLlLvEp@att.net> wrote:

the average isn't what matters. a quality app can be *very* profitable.

So can a lottery ticket, and it's easier to develop. Cheers, -- tlvp

whooosh.

 

[Stijn De Jong]

On Sat, 18 Feb 2017 23:13:31 -0800, Jeff Liebermann wrote:

This is a question and initial observation for Jeff Liebermann.
Why me?

Good question. I guess it's because I've seen so much made-up stuff from
the likes of nospam, that you're one of the few people here we can trust.

Does a cellular booster propagate the original cell tower identification?
(Or does the boosted signal have its own cell tower identification number?)

By "booster" are you referring to a bi-directional amplifier like
products from Wilson.

T-mobile gives out a signal booster where you put on unit in the window and
another unit in the middle of the house.
https://support.t-mobile.com/docs/DOC-14947

It's supposed to "boost" the signal.
https://support.t-mobile.com/community/coverage/personal-cellspot/4g-lte-signal-booster

If so, they repeat exactly the original signals both incoming and
outgoing. What you hear is the tower ID. The device does not
generate any new data or belch a new tower ID.

I think this is the case that the signal booster passes through the
original tower ID since I don't see any *new* tower ids when I hook up the
signal booster. Of course, it could just be that the signal booster isn't
working because the signal strength doesn't get any better either.

However, if you're referring to a Femtocell or similar internet
connected microcellular device, the answer is yes, they do have their
own unique ID.

I do have a femtocell also, and that *does* have its own unique ID which I
have identified already.
https://support.t-mobile.com/community/coverage/personal-cellspot/4g-lte-cellspot

So the question was just about whether the booster generates its own unique
cell id or if it just passes through the cell ID of a tower somewhere in
Santa Cruz or San Jose.

My initial assumption (which needs to be tested) is two fold:
a. It seems the router-connected micro tower has its own unique cell id.

Yep.

b. It seems the booster may simply propagate the "real" cell tower cell id.

Yep.

Does that make sense?

Yep.

Thanks. That made sense.
By the way, long ago you helped me set up a Linksys WRT54G as a wired
extender (yes, you cautioned against it in favor of better solutions).

Do you think it makes a difference if I hook up the femtocell to the wired
extender versus the main router?

How far away do you think the strongest (or nearest) T-mobile cell
tower is located from your test location?

The nearest tower is only a couple of miles away, but consistently I get
connected to towers that are ten and fifteen miles away. They bounce around
as I watch them from the MIT CellTracker app.

Any possibility that one of
your neighbors might have a T-mobile microcell box that you're
hearing? I'm suspicious of the rather strong tower signal.

Without the booster and without the femtocell, I get horrid signal, roughly
minus 90 to minus 105 decibels. With the femtocell, I get minus 60 decibels
consistently. I can even have stronger cellular signal strength than wifi
signal strength, which is amazing.

And, yes, *all* my neighbors have either a booster or a femtocell or they
use WiFi calling (since bad signal is ubiquitous in these hills).

Back of the envelope calculation:
+27dBm Estimated transmit power from the cell site
+10dB My guess of the panel antenna gain
-53dBm Receive signal level from your test.

Path loss = 27 + 10 + 53 = 90dB
Calculating the distance where the path loss would be -90dB at 700MHz:
http://www.proxim.com/products/knowledge-center/calculations/calculations-free-space-loss
is about 0.7 miles or about 4,000 ft. The cell tower would need to be
rather close to your location for that to work. Like I said, I'm
suspicious of what you're measuring.

Thanks for showing me how to do the math to approximate the distance to the
antenna based on the received signal strength indication.

I must not have stated clearly which is that the only time I get minus
sixty decibels is when the femtotower is in place, where it's only a few
feet from my phone.

Otherwise, I get around minus a hundred decibels, which sucks.
+27dBm Estimated transmit power from the cell site
+10dB My guess of the panel antenna gain
-100dBm Receive signal level from your test.

Path loss = 27 + 10 + 100 = 137dB
At 700MHz:
<http://www.proxim.com/products/knowledge-center/calculations/calculations-free-space-loss>
Puts the antenna at about 2 miles away.

There *are* antennas two miles away (and sometimes I connect to them); so
the math isn't as bad as I thought. I also connect to antennas ten and
fifteen miles away, but that's driving distance, so I'd have to look at the
distance as the crow flies, which could be in the less-than-five-mile
range.

 

[Stijn De Jong]

On Sun, 19 Feb 2017 13:46:55 -0800, Jeff Liebermann wrote:

I don't want to comment on the T-Mobile signal booster due to lack of
experience with the device and general lack of info on what's inside.
If you can supply an FCC ID number, I might be able to excavate
something useful from the FCC ID data dumpster.

Just returned from a hike in the mountains. It's freezing in the mountains
today. You are sending cold winds from Santa Cruz over the ridges!

T-Mobile calls *everything* a "Personal CellSpot" so, this is a photo of my
signal booster from T-Mobile:
http://i.cubeupload.com/6Jpa5v.jpg

On the back of the existing devices are these FCC IDs:

1. Window Unit: FCC ID YETD24NU
https://fccid.io/YETD24NU
User manual: https://fccid.io/document.php?id=2270465

2. Coverage Unit: FCC ID YETD24CU
https://fccid.io/YETD24CU
User manual: https://fccid.io/document.php?id=2270512

What I'm mostly interested is in figuring out how to tell if they're
working, since I can't seem to get different results with or without them
hooked up (and, of course, with the femtocell connected to my router turned
off).

I'm guessing based on the experimental results (which could be misleading)
that they just pass through the cell tower id.