GSM/GPRS connection from a balloon

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Hello Everybody,

Expert advise required on GSM/GPRS connection;

I want to send/receive data to/from a balloon carrying some sensor.
Initially balloon will be tight to a rope and will rise gradually in
human control.
It will send altitude, temperature, humidity, windspeed, GPS data via
GSM/GPRS module to a control computer and to a mobile phone on the
ground. It will also receive some remote control commands through the
same communication channel.

      - How high the balloon can rise before GSM/GPRS signal vanishes?
      - Is there a legal altitude limit for GSM/GPRS operation?
      - Which GSM/GPRS modules you would recommend for the balloon and
for the computer (please consider price and locality as Australia)?
      - Do you know any similar project or any open project which can
help me to learn more on GSM/GPRS data communication?


Thank you

Albert


Re: GSM/GPRS connection from a balloon


Please note this may not be accurate, going off memory.

Albert Goodwill wrote:
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I believe GSM has a 15km range, which would put anything over 50,000ft
out of range. However, I do recall reading a study conducted outside the
USA (due to FAA regulation) shortly after the 9/11 attacks to determine
the success rate of placing mobile calls on commercial flights - I
recall they found at altitude (although I can't remember exact figures
or have a link for you) the success rate was extremely low (less than
10%) over a sample data of several thousand calls - which apparently was
used to feed conspiracy theorists rubbish about that plane that crashed
in the middle of nowhere, and its passengers apparently called their
relatives from their cell phones, so who knows if said study was truely
accurate.

NextG apparently has 4x the range of GSM (or so goes the sales pitch),
but alot of the blokes on aus.comms.mobile don't like it.

Who knows, that information may be helpful. At least its some research
pointers for you.

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No idea about AU law, I do recall Mythbusters tackling the issue of cell
phones on planes who pointed out that in the USA its illegal under FAA
regulation on any passenger aircraft. Mostly because the equipment, such
as navigations & communications need to be tested to ensure they are
sufficiently shielded from interferance. I really don't think there
would be legal restrictions on a balloon, but a high altitude you will
need flight clearance.

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Nup, but you may be interested in packet radio as an alternative - with
a radio license its free on amatuer bands and can provide several
thousand kilometer ranges. Although the bandwidth is typically
compariable to dialup modem, but that should be plenty sufficient for
the data you stated. I suggest you see some aus.radio groups for info
about that ;)

Regards,
criten

Re: GSM/GPRS connection from a balloon


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That's a good suggestion regarding packet radio. Careful what you say on
the aus.radio newsgroup, there's a big bunfight going on there at the
moment.

Dorfus

Re: GSM/GPRS connection from a balloon



"Dorfus Dippintush"

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**   Huh  ???????

What aus.radio NG is that then ?

" aus.radio.amateur.digital "  is a classic example of the lights are on but
nobody is home.



......  Phil



Re: GSM/GPRS connection from a balloon



"Albert Goodwill"
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** You are going to run foul of the laws of Australia.

Tethered balloons must  NOT be flown to a height of more than 300 feet (
100m ) above the ground without a special permit from the Civil Aviation
Safety Authority  ( CASA)  -   plus you must be at least 4km away from  ANY
airport.

Also, the balloon must remain 500 feet below cloud at all times and be flown
only when there is perfect visibility.

So you CANNOT release the balloon.

Forget it  -  it's a totally mad idea.





........  Phil






Re: GSM/GPRS connection from a balloon



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If it's in a populated area then the mobile network operators might get
upset, and it is probably also illegal.

They may get upset because normally your line-of-sight (strong) signal gets
obstructed by hills and the curvature of the earth, and so the operator can
re-use the same frequency for many base stations that are not adjacent
cells to each other.  This works as long as a mobile phone is not in the
coverage area of two base stations that use the same frequency at the same
time.  Reusing frequencies means that they to bill several customers
simultaneously using frequency spectrum that they only paid for once.

If you transmit from a high altitude, you may have line of sight to several
base stations that all receive on the frequency that you're transmitting,
and your signal would interfere with the signals from other handsets on
that frequency even though those handsets are a long way away from your
location.  That means that using this particular frequency, the operator
can only bill one customer at a time (you) and they are not making a good
return on purchasing that frequency.

Chris


Re: GSM/GPRS connection from a balloon



"Chris Jones"
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**  ROTFLMAO    !!!!!!

Almost as misconceived and funny as "bassett" explaining how DTV works.




.........  Phil



Re: GSM/GPRS connection from a balloon


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Chris is actually correct. The original reason the FCC banned cellular
phones in any aircraft or balloon, was to prevent harmful interference
to terrestrial cellular systems. The original ban did not consider the
potential impact on aircraft navigation or communication systems.

When in the air, the distance to the cell tower causes the cell phone to
operate at maximum power, and this cause co-channel interference. The
current push is to have a pico cell installed in an aircraft, and this
will allow the phone to operate at minimum power levels, and prevent
interference to the ground based networks.

If cellular phones where that dangerous to the operation of aircraft, do
you really think that we would even be allowed to take them onboard?
Plenty of people "forget" to turn them off.

David



Re: GSM/GPRS connection from a balloon

"David" <
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**  Bullshit he is.


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**  Complete bollocks.

Mobiles operate at max power all over the place,  all the time.


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**  Purest crapology.

 Ever heard of the inverse square law  ??

 Obviously not -   it is not taught in IT courses.






.........  Phil



Re: GSM/GPRS connection from a balloon
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No, cellular phones adjust their output power to suit the current cell.
For small cells, the phones and the cell will operate at very low power
levels. This allows many phones to operate in a small area at the same
time while only using a limited number of channels.

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The inverse square law is the *exact* problem with cellular phones on
aircraft. When in the air, the distance from the cellular phone to the
cell towers on the ground is fairly equidistant, over a large footprint
on the ground. All the towers will receive the phone's signal at a
similar strength. This will cause interference with existing calls over
a large area on that channel. This is why the FCC and ACMA prohibit the
operation of cellular phones in an airborne aircraft.


When the cellular phone is on the ground, the tower closest will
typically take control, the phone will adjust its power level down, and
towers further away will have a much weaker signal (due to the inverse
square law).


Obviously they never taught about cellular phones at toaster repair school.

David



Re: GSM/GPRS connection from a balloon
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I dont know about GSM, but with CDMA, when it operates in a city area
(mostly full or near full signal all the time) the battery will last
for about 4 days.  When in country areas with low or no reception, the
battery will go flat in a day or less.

I always assumed that the phone raised its transmission power to
maintain the connection in poor signal conditions, thus draining the
battery faster ?










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Re: GSM/GPRS connection from a balloon

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Now usually you are right but this time you are not, and I can prove it.
Read the specification:

For GSM phones see page 12 of this:
http://www.3gpp.org/ftp/Specs/archive/05_series/05.05/0505-8k0.zip

For 3G phones, see page 22 of this document:
http://www.3gpp.org/ftp/Specs/archive/25_series/25.101/25101-780.zip

Anyway my first post did not mention the handset transmit power control
setting, I was referring to the fact that terrain and the curvature of the
earth help operators to be able to reuse frequencies at closer distances
than would be possible if handsets had line-of-sight to all basestations in
a city, like on a balloon.  This would be true even if maximum transmit
power were always used.

And as usual, insulting people will not make you right.

Chris

Re: GSM/GPRS connection from a balloon



"David" <


** Go find out what really happens in the USA

  Folk onboard  private aircraft do just what I posted.

   YOU  TROLLING     FUCKWIT !!





........  Phil








Re: GSM/GPRS connection from a balloon


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I never denied that they did. Doesn't mean that it is legal however.


David

Re: GSM/GPRS connection from a balloon



"kreed"

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 **  Try learning to read.

  Realise what I did  NOT  write.




........  Phil



Re: GSM/GPRS connection from a balloon
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 > Mobiles operate at max power all over the place,  all the time.

It is as you would say "complete bollocks", as mobiles do *not* operate
at max power all the time. They change their output power as needed to
maintain the required signal the tower the mobile has connected to.

David

Re: GSM/GPRS connection from a balloon



"David the Shit Head TROLL "
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** Try learning to read sometime.

Cos your reading comprehension is that of a genetically autistic fuckwit.

Which it is 100%  certain  you  ARE.





.......   Phil








Re: GSM/GPRS connection from a balloon


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** Try learning to write sometime. "All the time" implies continuously,
and clearly mobile phones don't operate at maximum power continuously.

My point is clearly proved, when all I get abuse as a reply from you.

David

Re: GSM/GPRS connection from a balloon


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Actually David, Phil is quite right, but ambiguous.
All of the time, *some* phone will be operating at full power.
Just not *all* phones, *all* the time.
You *both* failed to communicate clearly.

Re: GSM/GPRS connection from a balloon



"Clifford Heath"
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**  Not to anyone who can read English an follow a context.


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** What I wrote said there are lotsa mobiles phones, all over the country,
running at max power, at any time of day.

 Range to the tower has NOTHING to do with it.

 Signal attenuation in the pathway to one has.

 The phones all get along just fine.




.......  Phil







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