Will it work high?

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Expand view Topic review: Will it work high?

by mwolczko » Thu Sep 28, 2006 6:02 pm

madrabbitt(NSI) wrote: understand why your mountain example worked, but a aircraft at altitude would not work?
Plausible, but not definitive. The figure is captioned as qualitative, not quantitative. Also, the simple experiments described used voice comms; it may be that repeated attempts at sending a short data packet stand a much better chance of successful transmission. (Aside from that, perhaps it's worth mentioning that the cited page is part of a 9/11 conspiracy web site, making a lot of wild claims.)

by madrabbitt(NSI) » Thu Sep 28, 2006 4:24 pm

dammit. i closed the window as i was typing a reply.

first off, look at this picture (from the report linked in this thread)
Image

understand why your mountain example worked, but a aircraft at altitude would not work?


also, nextel, which does use 800 AND 900 spectrum, uses SMR spectrum, not cellular. Its a SMR radio, which has specific rules other then cell phone specific rules.
Yes, it would be prohibited to use a nextel on a manned aircraft, especially commercial.
Yes, you could use an SMR radio onboard an aircraft with pilot permission.

Neither of these really apply to the situation though.
An unmanned balloon doesnt operate under IFR, nor VFR.

It would be legal for the phone to be onboard the balloon, it just wouldnt work at those altitudes.

by mwolczko » Wed Sep 27, 2006 3:02 am

re: legality. There are some relevant links collected at http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft (see "Relevant Laws"). However, if you follow the link to reference 7 (http://www.house.gov/transportation/avi ... 5memo.html) you will see that Nextel is listed in the 800MHz spectrum, and therefore prohibited. If someone can show that the iDEN phones use 1.9GHz, that would reverse this tentative conclusion (but the Moto technical overview of iDEN I have, dated, Aug 2000, suggests that it use 800MHz). The relevant FCC ruling, 47 CFR 22.925 can be found at http://edocket.access.gpo.gov/cfr_2004/ ... 22.917.pdf.


re: feasibility. I have had an i415 connect to a cell tower 50 miles distant, which is over 250,000 feet. (See the map on http://www.ylem.org/Hitchhikers/HandP.html. If you zoom out a step, you'll see a cell tower located in San Francisco. The phone connected to this while on Mt Hamilton to the east of San Jose, 50 miles distant.) Of course, this may have been a fluke.

by madrabbitt » Sun Sep 24, 2006 4:19 pm

Jackichino wrote:It's an unmanned balloon, so I think it is legal to use.
re-read my second post.

nextel is a SMR radio, not a cell phone. In theory, its legal.

Then read my first post. It most likely wont work anywhere above 10-15.

It will work at any point that the balloon is low enough though.

So for a recovery purpose, it should be good for you.

Re: another question

by ATSupport » Sun Sep 24, 2006 2:35 pm

Jackichino wrote:Also, if it dosent work WHILE flying, would it send location when it goes down?
Certainly it'll work when it goes down to some point low enough but I don't know the limit. Might be a few thousands feet high I guess.

another question

by Jackichino » Sun Sep 24, 2006 1:48 pm

Also, if it dosent work WHILE flying, would it send location when it goes down?

by Jackichino » Sun Sep 24, 2006 1:44 pm

It's an unmanned balloon, so I think it is legal to use.

by madrabbitt » Fri Aug 18, 2006 3:41 pm

fyi. use of a cell phone on a plane, any plane, including a private plane or hot air balloon is still illegal in the states. the only reason i got away with it, it was a nextel, and a goverment owned nextel.

nextel is still technically a smr radio, not a cell phone.

which explains why the hot air baloon chase teams i've worked with use nextels rather then cells on the aircraft.

by madrabbitt » Fri Aug 18, 2006 3:39 pm

well.
the in-theory of that is, when you're up there, you're usually on a plane, and a cell can interfere with the plane's instruments, so thats a no -no.

at that altitude... yeah, you're probably not going to be able to reach a cell tower anyway.
Explaination on that, is the cell towers broadcasts are mostly linear. meaning they go out in cone shapes from the panels. Most of the time, they stay within a mile or two of the ground.

planes and other air craft are usually low enough to be able to aquire the signal. i've done it at 10,000 feet on a lear.
but the altitude you want, there is little chance of a signal.

by Skibum » Mon Aug 07, 2006 8:07 am

I don't believe you are allowed to use a cell phone at altitude.

by ATSupport » Mon Aug 07, 2006 12:09 am

We never used that way but I think it'll work if there's cell signal up there. But I really doubt the signal can reach that high. Here is a report that might help a bit: http://www.datasync.com/~rsf1/cell-air.htm it doesn't look like working.

Will it work high?

by Jackichino » Sun Aug 06, 2006 11:19 pm

I am looking to track a weather balloon that will be flying at about 80,000 - 100,000 feet. Would it be able to be tracked with one of these phones?

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