Which app do you use to scan/debug GSM/CDMA cellular tower signal strength?

I've been thinking of building (and selling) such a device. It can be done if:

1. You have an RF direction finder.
2. You know the sub-band where to expect the vendors transmissions.
3. You know the SID (system ID) of the vendor.
4. You have a map or database of the vendors service areas.

I used to design direction finders, so I have more than an average clue as to how this MIGHT be done. I'm not up to speed on cellular, but I think I can catch up. Basically, an SDR receiver that scans, looks for a signal direction, identifies it by RF sub-band and service area, draws a line on a map, and records the line. Drive around a little and soon you'll have many lines that cross at one point, which is the cell site. You won't get any ID numbers, but you can get those from any phone that can display the field service mode.

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

--
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

Thanks Jeff for that detailed explanation of why I seem to only see the one tower's cell id that I'm currently connected to.

My problem set is that I installed two different types of local microtowers and I just wanted to know which ones I'm connected to, and at what strength.

I have both iOS and Android devices, so it doesn't matter to me which I use (the iOS devices have far larger screens, so they're preferable).

After running the various programs since last night, I can say that there are two ways, overall, to get a "survey" of local towers.

1. The real-time apps, such as Network Signal Info, will constantly change their cellid as they move from tower to tower, so, with screenshots, I can capture that information for later use. (The tower changes seem to happen more when I have lousy signal strength than when I have stronger signal strength.)
2. The logging apps, such as Netmonitor & MyProfiles, seem to log the various celltower IDs so that we can see a history over time of the cell towers we have connected to.

Since they only show towers as numbers, it's hard at the moment to correlate these logs to the two microtowers I have installed. So I'm going to have to run a few surveys, near home (with and without the microtowers powered up) and away from home (to remove from the logs the towers that aren't within 1,000 feet or so of the house).

Over time, I should be able to figure out what the unique cellid of the microtowers is (which may be a function of their MAC address or serial numbers for all I know).

Following up on what Jeff Liebermann had suggested, and depending on your operating system, the Network Signal Info app seems to show you what cellular tower you're connected to, which then can be found on the maps within the app.

There are two important tabs:

1. Mobile tab
2. Cell Location tab

Here's the "Mobile" tab original screenshot:

And here's a screenshot of the "cell location" tab:

Given the unique tower cell id, you can also look up its location independently on the web, even down to the specific sector antenna that you're connected to.

Jeff, As an aside, I know extremely well a long-ago retired entrepreneur who made a few dozen millions on Google stock who lives a couple homes away who often funds enterprising people.

He runs a successful company that makes, sources, and sells technooid things, so, he might be interested in funding you (for a cut, I would guess). He also runs a local entrepreneur group that meets weekly on the peninsula and he's always invited by Google to the Google fairs.

He's extremely technical, if a bit liberal in his politics, so he'll understand everything technically that you'll be doing. At the very worst, he'll give you suggestions for improvement.

If you're interested, just say so, and I'll drop you an email. Otherwise, just ignore.

I

I have not had any issues running OpenSignal.

I can only tell you that while Verizon has good coverage with at least two towers where I live, T-Mobile is mediocre and shows no towers, and both AT&T and Sprint are poor to non-existant, also showing no local towers. This leads me to believe that T-Mobile, At&T, and Sprint are actually roaming in my location, using the Verizon towers.

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Regards, 

Savageduck

sprint probably is, but att/tmo aren't.

The Network Signal Info app has three fields that may indicate which carrier "owns" the network you are using:

1. Net operator (that has two fields currently T-Mobile / T-Mobile)
2. Sim operator (that has one field currently T-Mobile)

Here's a screenshot from the original post of those three fields:

All three of those fields, currently, are showing T-Mobile on my phone, but, it might be that the net operator could show roaming by showing different carriers in the first two fields?

There is also a "Roaming" section at the bottom, where, in mine it says: Roaming: Roaming is OFF

It may be that, when you're roaming, you can see that roaming is on, and then you might see a net operator of something like: Verizon / Sprint Instead of Verizon / Verizon

AT&T coverage out here at Lake Nacimiento, West of Paso Robles, is mostly bad to non-existant. That was my reason to not having an iPhone until Verizon came onboard, and I seriously doubt that they are making any effort to solidly establish their presence here in any competitive way. T-Mobile does have much better rural coverage than AT&T, but nowhere as good as I get with Verizon. As to whether or not any of them are using Verizon towers for roaming, that is only conjecture on my part.

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Regards, 

Savageduck

it's not conjecture on my part.

sprint/verizon have roaming agreements, as does att/t-mobile.

historically, sprint/verizon used cdma while att/tmo were gsm/hspa. the two air interfaces are not compatible, so they *can't* roam on each other's network.

now that all four carriers support lte, it's technically possible, except that each carrier uses their own set of lte bands and not all phone models have all of them (i can think of only 3-4 that do), so it's not a realistic option. if they did offer it, most people would not benefit.

roaming is usually just for voice/text, not data, however, it depends on the specific plan, and there may be additional fees in some cases.

tl;dr - coverage varies. choose the carrier who has coverage in the areas in which you travel and at a fair price. do not count on roaming. there is no single 'best' for everyone.

That is not possible.

--
I thank my lucky stars I'm not superstitious.

For CDMA femtocell, the unique ID is a conglomeration of: MCC (Mobile Country Code) SID (System ID) NID (Network ID) BID (Base Station ID)

For GSM femtocell, it's: MCC (Mobile Country Code) MNC (Mobile Network Code) LAC (Location Area Code) CID (Cell ID)

Stolen from: Read the footnotes, which have some Android bugs listed.

--
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

OK! In that case, I will put it bluntly; AT&T, T-Mobile, and Sprint

Paso Robles, California totally sucks. Conversely Verizon coverage is actually quite good in the same area, particularly given that the only towers in the area belong to Verizon.

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Regards, 

Savageduck

Of course you have to choose your mobile carrier based on your own coverage needs. Traditionally Verizon has had the largest coverage area, though t-mobile has been making large gains in recent years.

I get good coverage all over Denver, but it is pretty lousy inside my house, so I have a (free) T-mobile CellSpot that provides LTE coverage inside the house (and almost certainly improves the coverage for my neighbors).

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Not all who wander are lost

There is no way the phone can determine the location of the tower from the signal, the antenna is non-directional. It has to be determined from a map of locations. Maybe the tower gives that info, I don't know.

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Cheers, 
       Carlos E.R.

You could also add some LTE/UMTS module, some of these can do a network scan with an AT-command and give you the cell id, technology, channel number etc. of all 'visible' base station.

Apparently even some USB dongles can do this, so you could connect some cheap SDR+modem+GPS to an RPi and do your magic.

There are also cell tower location databases like Opencellid.

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mikko

I've had all three, Verizon, AT&T, and T-Mobile.

Out here in the Silicon Valley, coverage seems about the same for each, although I had them in series, and not sequentially (except for a few concomitant burner phones).

< off topic observation > I dropped Verizon when they added a two-year contract just for replacing a Kyocera phone that broke which I had under an insurance plan. That's where I learned the insurance plan had gotchas they don't tell you about; so the second that the additional two years were up, I went to AT&T (and saved a few bucks, as it turned out).

I kept AT&T for about 4 or 5 years until I needed a plan sans data for my family plan. The Blackberry was grandfathered, but AT&T wouldn't allow me to have what they called a "smart phone" without data, even though they'd happily block data (saying it was for "my protection"). I dropped AT&T like a hot potatoe like I dropped Netflix when they changed their plan, and never looked back on either one.

Moving to T-Mobile, I loved that they did everything differently. I mean everything. I could buy my own phone. No contract. No data overage charges ever. Calling Europe was 20 cents a minute. Data is unlimited in Europe. No roaming charges. And, I didn't have to have data if I didn't want it. I could get phones from them for an additional $50 over what I could get on the market, where they'd charge me 1/24th the phone on the bill. I didn't even have to tell them what phone I was using. Everything about T-Mobile was different than Verizon & AT&T.

And the coverage was about the same (sucky in the mountains, great in the valley) for all three.

< / off topic observation >

they do.

long ago, i used to put an old flip phone into service mode and see the lat/long of the towers as it handed off.

you can buy your own phone with any carrier.

until recently, the carriers would have preferred that since you would have been paying a subsidy for a phone they did not subsidize. that's more money for them.

now that they've mostly separated the phone price and the plan price, they don't really care. sure, they'd love it if you bought it from them but if you bring your own that's fine too (as long as it's compatible with the network).

you don't have to tell any carrier what phone you're using.

they already know.

Coverage maps:

Dunno exactly where you are, so I have to just look at the lake itself.

If I pick the area under the words "Lake Nacimiento" on the map as the point of reference, it seems that T-Mobile and Verizon are about the same, while AT&T and Sprint suck by way of comparison.

AT&T:

Sprint:

T-Mobile:

Verizon: