Mobile Satellite Internet Connections?

Anml4ixoye asks: "I am currently the webmaster for Hillsborough County, FL. Yesterday I had a meeting with the chief of Fire Rescue and they have a challenge. Our incident-command vehicle currently uses a cellular connection to the internet when a hard-line is not available (at the rate of 18c a min). They would like to switch to satellite internet, but need a way to automatically position the dish that is used. We're talking firefighter proof (as simple as possible). Any ideas on who to use, how to accomplish this, etc?"

Comments

go for the freebies!

[psychosis]

Heh, you could just drop an 802.11b card into the system and hope the incidents happen where a kindly company has a wireless network for you to access...

Seriously, though, if you're talking about a mobile home-style command center, there are attachments to the directv dishes that make it pretty easy to aim them. I'd assume that holds for the DirecPC dishes too.
Nevermind - I just remembered that the direcpc system needs a phone uplink, so that won't work.
maybe just get a cheaper cellular connection? My Sprint one is much less than $0.17/min.

Can satellite compete?

[Matt_Bennett]

Is it just a cost issue or is is an availability issue? I think it would be pretty hard to beat $0.18/min with satellite. For a previous job, I took a long trip on a ship and our only internet connection was via Inmarsat (and analog modem)- which, if I remember correctly, was at least $1.00/min.

If you want automatic positioning- check out the satellite antennas that they put on boats- they have 3 axes of gimbal so that they will continue to point at a satellite while the ship is moving at sea- your problem should be a bit easier, since you probably don't need the connection while moving.

Iridium

[PatJensen]

Iridium offers data capability at 9600 baud via satellite phone with a serial interface. You dial up as normal using dial-up networking. I think they charge near $1/minute. Not too bad since taxpayers foot the bill anyways.

I'd rather pay $1/minute then have my house burn down. The phones feature decent battery life, don't need to be aimed at all, could probably tie into a DC adapter into the vehicle.

Also I believe Inmarsat and other satellite data providers have similar offerings. Hope this helps.

Pat

A little more info...

[Anml4ixoye]

Thaks for the answers so far. Just a little more info. Realize first that this is not used to transmit fire ground communications. The primary purpose of the vehicle is extended operations, such as New York, where we expect to be on the scene greater than two days. The Internet connection is used to get weather updates, haz-mat information, and communicate with Headquarters.

Unfortunately, due to the size and wierd shape of our county, Ham radios would probably be out. And, because we have 900mhz radio communications, relatively unnecessary. And Satellite Internet is being advertised here for 39.95 per month, which would be a substantial cost savings to the taxpayers. (Yes, we actually care about you all).

And maybe there isn't a system, but if anyone has creative ideas of how to build one, that would be appreciated as well. Thanks again!

Re:A little more info...

[duffbeer703]

You might want to hold off a little while

I know SprintPCS and other cell vendors are rolling out high-speed wireless networks in Arizona and new mexico.

I think the cost is alot more reasonable than normal cellular packet data too.

Otherwise depending on LOS and other issues, you might want to consider using microwave trucks like the tv stations use. I know a town near me (Bethlehem, NY) uses a van with a microwave transmitter to relay to HQ when there is some sort of problem on the far side of town near the river.

Best of luck.

There is a 2 way satellite system on the market.

[UnifiedTechs]

I know it is taboo to say on /. but Microsoft(MSN) has a 2 way satellite system out. For this situation I am sure you could contact them directly, they may be interested in working out a solution for easy/automatic aiming with you to be able to offer it to other emergency departments.

Worst case scenario is you buy one of their signal meters for aiming and spend 5 minutes with the trucks driver to teach him how to aim it in the general compass direction and then move it till the little arrow is as high as possible. Best case is MSN is able to devise a motorized system that auto tracks to the strongest signal. I'm no Electronics tech but I'm sure it can't be that hard to integrate a motor and small basic ROM to track the dish towards the strongest signal. Since time is not a factor it could spend 5 to 10 minutes to track the dish in every direction and then return to the strongest point, even faster if you integrate some logic to cut out obvious bad areas based on an electronic compass or relative signal strength in neighboring sectors.

Ask the boaters

[bluGill]

I know sailboaters (see various races around the world) use satalite communication, and their conditionsare much harsher than what you need to deal with. They have equipment that can keep the dish pointed even in seas too rough to accually use the connection. I'm sure power boats have the same system though i've not heard of it.

Sorry I don't know more details, but at least this is a direction to look.

Not Just Yet

[jheinen]

They two-way providers that have been mentioned unfortunately only work with fixed stations at the moment. The mobile automatic dish-pointing equipment is currently not up to the precision needed to point at the satellite. There are systems which work for satellite TV, however it is much easier to point a dish to receive than it is to transmit (to receive, you don't have to be that accurate, when sending from a dish however, you have to be pointed pretty much *exactly* at the satellite).

-Jeff

must be do-able

[budgenator]

In the army I worked on radar-doppler seeking guided missiles, and basicaly what we did was to place a rotating scanner in front of the feed (LNB in satalite talk). When the dish was pointed dead on, the signal came through clean, if it was off axis the scanner started to chop up the signal.
Measuring the amount of chopping gave the magnitude of the error, measure the phase of the chopping gave the direction of the error. Feed these error back through some electronic and drive a few servos on the mount and your done.

To use the system,

1. you could program a box-search algorythm to automaticaly fine tune it after you got it close.
2. You'd probably have to set the van up on sturdy jacks, someone walking arround on a vehicle supported by inflated tires, on sprung axles would surely through off alignment on a sat 22,400 mile away. (ground mount would help here also)
3. Get the installer to align the thing on the satalite, so that its working correctly. (slip him a little cash on the side to get him to do it as exactly as possible :)
4. align the scanner for zero error signal
5. turn on the aiming system and see if it drifts off axis
6. If it didn't drift off, manualy move it off axis and see if it returns

As for the need for absolute presition, I don't buy it becuase

1. the dish isn't that fast, as in telescope or photography fast, they look to be only about F 0.5- 0.7 in other word wide angled, and low gain
2. The dish itself is rather small, the really directional stuff is about 10 wavelengths, these dishes only look about 3 or 4 wave lengths
3. A modern amature telescope mount can with a little intervention hold on a star for several hours worth of exposure time
4. the dish installer aren't all rocket scientists and they need to make a living too, so it realy can't be that hard
5. the alignment technic is loosen the bolt turn the pipe, tighten the bolt and hope the thing doesn't jerk out of alignment a worm gear could change alignment increments from degrees to seconds of degrees!
6. Even when its perfect today those birds do drift a little, they're not exactly over the equator all of the time! they must tend to pull towards the line connecting the center of mass of the sun and the Earth and the equator is only on this line durring the equenox's anyways.

perhaps you can get an amature telescope manufacturer or amature astronomer excited with this idea in return for the potential sales, there must be a lot of fire-departments and other emergency services that need communtications such as Email or looking up an MSDS on a disaster site. My thaught is it may be impossible to do this on a mobile basis as in moving vehicle, but fairly easy to do on a mobile basis as a fixed location that occasionaly moves. Just have to start thinking outside the box here.