Wireless data links for telemetry, south-eastern US?

What distance between the deployed unit and the base? I wonder if there are any unlicensed bands that you could use (49MHz springs to mind, but I'll bet that it's not for unattended data).

Of course, just using a cell phone is a heck of a lot easier...

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On a sunny day (Mon, 14 Sep 2009 11:58:41 -0700) it happened Joerg wrote in :

Only sat phones work nearly everywhere.

That can be hundreds of miles.

Yeah, we will need some sort of established network and there should be reasonably priced RF to RS232 thingamagics available.

That is certainly an option but I've heart that is prohibitively expensive. Also, it must work with a rubber-ducky or similar antenna, nothing that requires alignment (the units can get shoved around a bit).

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OMG a real SED post...

Let's see how long it takes for this thread to go into politics :-)

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Some operators offer data only service at a reduced price especially for such applications. You might want to look into that (call their busines sales department).

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We will. Alarm companies use that service. However, there are a lot of carriers. Often they promise you a rose garden when it comes to coverage and the online maps are rather coarse. So I was hoping there'd be someone who was involved in something like this in the south-eastern part of the country. I live in the western part and out here I'd probably approach Sprint or one of their resellers because my cell is on their network and coverage is great.

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Sat phone for remote stuff. Regular cell for urban. AT&T is the best bet. (Cingular Network) You'd need a nation wide plan, or set the phone up in the area you plan to place it to avoid roaming charges.

Cheers

Cheers

But doesn't that require a directional antenna? That wouldn't be feasible in this scenario. Probably very expensive as well. Most of it is just broadband like this:

Regular cell for urban. AT&T is the best

Thanks. So AT&T is the best bet down there? In this area that's not so hot after they went GSM. A neighbor had to put a yagi antenna onto a plastic pole so his cell phone wouldn't quit in the house. Now he has a tethered cell phone ... until the plan runs out.

Roaming charges are unacceptable and could be negotiated away. After all, I don't pay any on my own cell. It's always 18c/minute no matter what or where.

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I was thinking of something such as this...

88c/minute, 99c/minute, yikes. I don't think my client would like that :-)

Unless they have a lower cost data option. Thanks for the hint, I'll certainly give them a ring. The other question will be the cost of a radio modem but I'll find that out as well. Operationally it would certainly be a very smooth option because it can work overseas. The GlobalStar satellites could be interesting.

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It just did. :(

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I have all (well, most of) the cell site & cell tower locations and spectrum/technical data in the southeast US. Most of data is proprietary, so it cannot be shared.

However, I can tell you Verizon and AT&T would likely be your best bets overall (as far as raw number of sites, coverage and network capacity), but I'm not sure what kinds of data / telemetry plans each offers. The devices would be uniquely identified on their respective networks (federal law), but they may be willing to bundle a plan depending on revenue, etc.. I know AT&T does have (or used to have) a division that dealt exclusively with machine-to-machine telemetry using the cellular network, but that was back in the days of CDPD, which has since gone the way of analog... . I wouldn't waste my time with customer service. You'll need to find someone higher up in the food chain. I'll try to get you the right contact at AT&T.

That said, depending on your intended purpose, I'm wondering if you may find the FCC has spectrum allocated for your needs? It may indeed be cheaper to use a public network (like cellular/PCS), but without knowing the application & budget, it's hard to say. Satellite is expensive -- moreso than cellular / PCS, but it does have better coverage. And (as previously mentioned), usually requires antenna alignment.

As for costs, there the initial upfront (for the hardware / terminals), and the ongoing monthly expense for airtime billing, etc.. Plus, you'll have to consider power (solar?) for those sites in the "boonies". I mention this only because (by experience) you can't always rely on carribean mains power... :)

I assume you have also considered Hurricane impacts to those public networks. After most storms, large chunks of the cellular / PCS networks go offline. Usually, these are related to widespread power outages (after gensets run out of fuel and batteries fail). But usually 90% or better restored within a few days (Katrina, Ivan, Andrew, Wilma & Charley being notable exceptions) Expect worse performance from Batelco / other carribean carriers.

Also, in the Bahamas, last I heard the best you could expect was EDGE technology on the larger islands. The smaller islands. GSM - maybe, but likely little if any reliable coverage. And a lot of those GSM systems were voice only. No data. Of course, you won't have that problem stateside.

I understand. Just wish they'd have more meaningful and detailed coverage maps with signal level lines and such.

Thanks. I believe Verizon uses CDMA and AT&T uses GSM so modem costs would go up if we must use both. My preference would be CDMA networks if there's a choice.

Yes, we will try that.

We can't really have out own receivers and antenna towers. Otherwise it would indeed be cheaper and in some areas more reliable.

Yesterday I have written to Globalcom, the company Martin suggested. No response yet which is a wee bit disconcerting, but we'll see.

Oh, we've got our experience there, too :-)

That would be ok. Mostly it doesn't matter if the data is transmitted during or after the storm. Even in the clean-up phase the equipment won't likely be used anyhow, people have other things to worry about then.

Voice only could be done as well, using plain old audio modem technology. Even 1200bd over a crackly link would be plenty fast here.

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At least in this part of the SE, Verizon is the only game outside of town. They all work in the cities but go outside a few miles and nothing.

That would be a serious problem for us. Got to avoid situations where the installer realizes "Oh s..t, it doesn't work out here".

So you think Verizon might be the better deal? The nice thing is that (IIRC) it would then be CDMA.

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Better than nothing? I use Verizon, mostly because of the deal my PPoE had with them. My contract is up but the phones, amazingly, still work. I see no need to give them a chance to review my contract terms so I'll hang with the old contract for a while.

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The newer seismic sensors I run into in the boonies are using Wild Blue internet. About $50 a month, but not a rubber ducky service.

The phone companies in the past have been notoriously nasty (more than they usually are) for data services. San Jose had set up their sprinklers using a cellular service. The service changed, wasn't compatible, and the phone company said "Hey, sorry about that."

If you could get the data rate down, pagers would be a path to investigate. There is an amazing amount of digital crap on pagers these days, especially two way paging. Alarms of all sorts. Stuff I probably shouldn't mention but critical to the infrastructure.

There is a GSM company that exists strictly for roaming. [Commnet.] I've been in some real remote areas and found their towers.

Not everyone knows about these towers since their provider may not have roaming agreements with them. There are tricks to sniff out these towers, but they are cell phone dependent.

Google has a cellsite database. They bought a company to get it. Unfortunately, the database is pretty poor when it comes to GSM.