What would it take to get reliable 900mhz cell coverage in the air

twdeckard said:
http://www.wdtinc.com/pages/home_page/iMapWeather/imap_mobile/webpage_category.xml

I would drag an antenna that reached down to the ground if this worked ...

Todd
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First the US does not have 900Mhz Cellular, we use the 850MHz band for that BTAITM.

http://www.aircell.com/ has the service already up and running.

The FCC regs apply to cellphone operating in the 800MHz band.

See part 22.925

§ 22.925 Prohibition on airborne operation of cellular telephones.

Cellular telephones installed in or carried aboard airplanes, balloons or any other type of aircraft must not be operated while such aircraft are airborne (not touching the ground). When any aircraft leaves the ground, all cellular telephones on board that aircraft must be turned off. The following notice must be posted on or near each cellular telephone installed in any aircraft:
“The use of cellular telephones while this aircraft is airborne is prohibited by FCC rules, and the violation of this rule could result in suspension of service and/or a fine. The use of cellular telephones while this aircraft is on the ground is subject to FAA regulations.”
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Part 24 is what governs the use of the 1.9GHz cell operation and there is no mention of any restriction of the use of the phones in the air.

All that being said, with one exception, the cell systems and PCS systems are designed and optimized for terrestrial use. When I am in my office I can barely use my cell phone anymore as I have been moved into a corner office and get far too much interference from all of the surrounding cell sites that my phone can 'see'. I actually have to walk towards the inside of the building to use my phone.
 
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I wonder if some sort of directional antenna would help. Aim at some area and give it a shot. Seems plausible, no?

I've gotten a signal up at 19,000' once. Dropped the call that I was trying to make, though :(
 
sba55 said:
I wonder if some sort of directional antenna would help. Aim at some area and give it a shot. Seems plausible, no?

I've gotten a signal up at 19,000' once. Dropped the call that I was trying to make, though :(
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I have found that, when I am in a relatively remote area, I can get a usable signal at a reasonably high altitude (8,500MSL / 6,000AGL), for use with 3G data modem; presume voice would work as well.

Like you, Felix, I presume that a relatively narrow-beam antenna would work best, to avoid hitting too many sites at once.

Catch is, finding an antenna which is wider-pattern than a beam, not omni, not giant.

In Australia, pilots are routinely able to use their GSM service while in flight.
 
SCCutler said:
I have found that, when I am in a relatively remote area, I can get a usable signal at a reasonably high altitude (8,500MSL / 6,000AGL), for use with 3G data modem; presume voice would work as well.

In Australia, pilots are routinely able to use their GSM service while in flight.
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That has been my experience. Over rural area where cells are really spread out and relatively flat, the system sees the phone on only a few cell sites.

Over more populated areas, the system sees the phone on far too many sites and rejects it to prevent the phone from tying up the same channel on dozens (or in some cases hundreds) of sites.
 
PilotAlan said:
Over more populated areas, the system sees the phone on far too many sites and rejects it to prevent the phone from tying up the same channel on dozens (or in some cases hundreds) of sites.
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It was actually due to too much signal. While some cellular technology, CDMA notably, works in hig interference environments, GSM does not. To mitigate interference a lot of little tricks are used with antennas but also parameters such as timing advances and it makes it really difficult for fast moving traffic that is not in the direct expected pathways of the cellsite.

The AirCell guys that I mentioned above use anntenna patterns and a different traffic model with the expectation of fast moving higher altitude coverage. Their system works int he air while jsut about everything else is hit or miss.
 
smigaldi said:
First the US does not have 900Mhz Cellular, we use the 850MHz band for that BTAITM.

http://www.aircell.com/ has the service already up and running.

The FCC regs apply to cellphone operating in the 800MHz band.

See part 22.925

§ 22.925 Prohibition on airborne operation of cellular telephones.

Cellular telephones installed in or carried aboard airplanes, balloons or any other type of aircraft must not be operated while such aircraft are airborne (not touching the ground). When any aircraft leaves the ground, all cellular telephones on board that aircraft must be turned off. The following notice must be posted on or near each cellular telephone installed in any aircraft:
Click to expand...
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I can just see it - trying to make a legal call when I am making a landing:

"Hi - click"
"Back on the ground- oops click"
"We just landed - oops gotta go - click."
"Ok, this time I think we will stick..."
 
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