'Project Achilles' Report
Part One - January 23rd 2003
Preliminary low-altitude cellphone experiment
January 23 2003; 4:35 - 5:40 pm
Civic Airport, London, Ontario, Canada
Equipment:
aircraft: Diamond DA20/C1 Katana two-seater
engine: 125 hp
fiberglass/carbon fiber composite body & airframe
weight fully loaded: 1630 lbs
cellphones: one Motorola model "120 CDMA" cellphone (A)
two Motorola "i1000 plus" cellphones (B)
(both fully charged at flight time)
The flight plan consisted of four "laps," elongated circuits (shaped
like a paperclip) over London, Ontario airspace. Each lap was about seven to
eight miles long and two to three miles wide. Three calls were made on each
of two straight legs in each lap. Calls alternated between cellphone A and cellphone
B. A second i1000, intended for use at higher altitudes, slipped to the cockpit
floor and could not be retrieved in those cramped quarters. A check of battery
levels of the first i1000, however, showed that there had been no significant
power drain on the unit.
* * * A * * * * * B * * * * A * * * * end
*
* W ----- E
*
*
* * * B * * * * * A * * * * B * * * * begin
Note: "altitude" means aboveground altitude, not height above sea
level, as recorded by the altimeter.
Results:
Lap 1 @ 1,100 feet altitude |
1st leg: |
A to business number |
no connection? |
|
B to business number |
1 min. complete |
|
A to business number |
1 min. complete |
2nd leg |
B to home number |
no connection? |
|
A to home number |
(broken) complete |
|
B to home number |
complete |
Lap 2 @ 2,100 feet altitude |
1st leg: |
A to home number |
no connection? |
|
B to home number |
no voice, just a "beep" |
|
A to home number |
no connection? |
2nd leg |
B to home number |
1 min. complete |
|
A to home number |
no voice |
|
B to home number |
no voice |
Lap 3 @ 3,100 feet altitude |
1st leg: |
A to home number |
missed making the call |
|
B to home number |
"system busy" |
|
A to home number |
incomplete |
2nd leg |
B to home number |
"please wait: CLEARNET" |
|
A to home number |
incomplete |
|
B to home number |
call made late, incomplete |
Lap 3 @ 3,500 feet altitude |
A to home number |
incomplete |
|
B to home number |
complete, but breaking up |
|
After the third call, I decided that the cockpit was too noisy to hear the
message system, so I changed my plan and called home (my wife), instead.
Calls to the business number were recorded by the message system. Two calls
made it through. Of the 17 calls to the home number, only about ten calls got
through. In three of these, we had a conversation (of sorts) and the rest were
just white noise. (no record of which)
Summary:
In the preliminary test, only five of the 16 (attempted) calls resulted in
any meaningful voice contact. In at least two of those calls, no connection
whatever could be established with cellsites below. The composition of the Diamond
Katana (manufactured right here in London, Ontario) makes it almost transparent
to EM radiation at radio wavelengths and the results of this experiment are
therefore optimal. Aircraft with metal skins will undoubtedly fare rather worse
in the percentage of calls making it through.
Altitude Range |
Range in Feet |
Call Success Rate |
Percentage Success Rate |
low altitude |
1100' - 2100' |
4/12 |
33% |
mid altitude |
3100' - 3500' |
1/7 |
14% |
Conclusion:
The purpose of this experiment was to probe the effect of altitude on cellphone
service and to iron out wrinkles in experimental procedure. In the first instance,
it looks as though there might well be a decline in service with increasing
altitude. The phenomenon must now be mapped more carefully.
As far as operating procedures is concerned, it is probably best to make calls
to a number you know well, to be familiar with the various status messages on
each cellphone display screen, and to have someone at the other end who can
log the time of the call, as well as to summarize the content. (The cockpit
in most light aircraft is so noisy that one cannot always hear a voice at the
other end, although I did hear my wife talking somewhat clearly on two occasions.)
Also, it is important to be very organized, having a special carrier case for
cellphones, writing/recording materials, etc. The airspeed of the Katana was
just a little fast for me to comfortably make the calls and stay organized at
the same time. Two of the calls were made rather late in the current lap, even
as we began to climb out to the next one. It would be better to have a separate
person operating the cellphones. We also need a meaningful call classification
system to fill the gaps between complete failure and an audible conversation.
All calls were handled by the Bell Mobility Network, which has some 25 cellsites
operating in the London area. I have now located all the cellsites in London,
Ontario, thanks to a very helpful set of maps provided by a local cell phone
aficionado: <www.arcx.com/sites/>
Plans are now under way for Part
Two. This will involve a Cessna four-seater (with an aluminum skin), five
or six cellphones of various types, an expert to operate them on my queue, and
a flight plan that will explore the effect up to 10,000 feet beyond which, according
to one airline pilot, there is absolutely no hope of getting through.
A. K. Dewdney
(with thanks to Corey Barrington, pilot with empire Aviation)
'Project Achilles' Report
Part Two - February 25th 2003
Equipment:
- Diamond Katana four-seater (Empire Aviation)
- cellphones: C1, C2, C3, C4 (See appendix for descriptions.)
Personnel:
- Corey Barrington (pilot)
- Darren Spicknell (operator - technician for Wireless Concepts, Inc)
- Kee Dewdney (director)
- Pat Dewdney (ground recorder)
Weather: unlimited ceiling, light scattered cloud at 3,000 and 25,000 feet,
visibility 15 miles, wind 5 knots from NW, air temperature -12 C.
For this experiment, we flew a circular route, instead of the elongated oval.
The circle centred on the downtown core and took us over most of the city suburbs.
All locations below are referred to the city centre and are always about three
miles distant from it.
Protocol:
At times specified by the director, the operator made a call to a specified
number, stating the code number of the cellphone (1 to 4) and the altitude.
The receiver recorded whatever was heard and the time the call was received.
At the first three altitudes of 2000, 4000, and 6000 feet abga each cellphone
was used once. At 8000 feet abga, only C2 and C3 were tried, C1 and C4 now being
hors de combat.
Results with timeline:
Time (pm) |
Call No. |
C# |
Loc. |
Operator Recorder |
5:05 |
|
|
|
started taxi to runway |
5:12 |
|
|
|
takeoff |
5:14 |
|
|
|
at 2000 feet (above-ground altitude) |
5:15 |
Call #1 |
C1 |
N |
success not very clear |
5:17 |
Call #2 |
C2 |
W |
success not very clear |
5:19 |
Call #3 |
C3 |
SW |
failure |
5:21 |
Call #4 |
C4 |
S |
success not clear/ breaking up |
5:24 |
|
|
|
climbed to 4000 feet abga |
5:25 |
Call #5 |
C1 |
NE |
failure |
5:26 |
Call #6 |
C2 |
N |
success clear |
5:27 |
Call #7 |
C3 |
NW |
failure |
5:29 |
Call #8 |
C4 |
W |
failure |
5:33 |
|
|
|
climbed to 6000 feet abga |
5:34 |
Call #9 |
C1 |
SE |
failure |
5:36 |
Call #10 |
C2 |
E |
failure |
5:37 |
Call #11 |
C3 |
NE |
failure |
5:38 |
Call #12 |
C4 |
N |
failure |
5:39 |
Call #13 |
C1 |
NW |
failure |
5:40 |
Call #14 |
C2 |
SW |
success clear |
5:42 |
Call #15 |
C3 |
S |
failure |
5:43 |
Call #16 |
C4 |
SE |
failure |
5:44 |
Call #17 |
C1 |
E |
failure |
5:45 |
Call #18 |
C2 |
NE |
failure |
5:45 |
Call #19 |
C3 |
NE |
success breaking up |
5:46 |
Call #20 |
C4 |
N |
failure |
5:49 |
|
|
|
begin climb to 8000 feet abga (cellphones 2 and 3 only) |
5:50 |
Call #21 |
C2 |
W |
failure |
5:50 |
Call #22 |
C3 |
SW |
failure |
5:51 |
Call #23 |
C2 |
S |
success buzzy |
5:53 |
|
|
|
completed climb to 8000 feet abga |
5:58 |
Call #24 |
C3 |
SE |
failure |
5:58 |
Call #25 |
C2 |
E |
failure |
5:58 |
Call #26 |
C3 |
E |
failure |
5:59 |
Call #27 |
C2 |
NE |
failure |
6:00 |
Call #28 |
C3 |
N |
failure |
6:01 |
Call #29 |
C1 |
N |
failure |
6:01 |
Call #30 |
C2 |
NW |
failure |
6:02 |
Call #31 |
C3 |
NW |
failure |
6:02 |
Call #32 |
C4 |
NW |
|
6:15 |
|
|
|
landed at airport |
Conclusions:
To the extent that the cellphones used in this experiment represent types in
general use, it may be concluded that from this particular type of aircraft,
cellphones become useless very quickly with increasing altitude. In particular,
two of the cellphone types, the Mike and the Nokia, became useless above 2000
feet. Of the remaining two, the Audiovox worked intermittently up to 6000 feet
but failed thereafter, while the BM analog cellphone worked once just over 7000
feet but failed consistently thereafter. We therefore conclude that ordinary
cellphones, digital or analog, will fail to get through at or above 8000 feet
abga.
It should be noted that several of the calls rated here as "successes"
were difficult for the Recorder to hear, witness description such as "breaking
up" or "buzzy."
Summary table
Altitude (in feet) |
Calls Tried |
Calls Successful |
Percent Success |
2000 |
4 |
3 |
75% |
4000 |
4 |
1 |
25% |
6000 |
12 |
2 |
17% |
8000 |
12* |
1 |
8% |
* includes three calls made while climbing; last successful call was made from
just over 7000 feet.
The four cellphones operated via four different cellular networks (cellsites).
Because calls were made from a variety of positions for each network, it cannot
be said that failures were the fault of cellsite placement. the London, Ontario,
region is richly supplied with cellsites belonging to five separate networks.
It may be noted in passing that this experiment was also conducted in a radio-transparent
aircraft with carbon-fibre composite construction. Failure to make a call from
such an aircraft with any particular brand of cellphone spells automatic failure
for the same cellphone from a metal-clad aircraft flying at the same altitude.
A metal skin attenuates all cellphone signals to a significant degree. It may
safely be concluded that the operational ceiling for cellphones in aluminum
skin aircraft (most passenger liners, for example) would be significantly lower
than the ones reported here.
It may therefore safely be concluded that cellphone calls from passenger aircraft
are physically impossible above 8000 feet abga and statistically unlikely below
it.
A. K. Dewdney
February 25/03
Appendix - Cellphone types, networks (courtesy of Darren Spicknell)
C1 Motorola i95cl - Telus Mike Network - 800 Mhz IDEN
C2 Motorola StarTac - Bell Mobility - 800 Mhz Analog
C3 Audiovox 8300 - Telus PCS Network - 1.9 Ghz CDMA / 800 MHz
C4 Nokia 6310i - Rogers AT&T - 1.9 Ghz GHz GSM. (Tri-Band - Has an
1.8 GHz and 900 Mhz GSM these are European frequencies)
IDEN - Integrated Digital Enhanced Network
CDMA - Code Division Multiple Access
GSM - Global Systems for Mobile Communications
Power Levels
Power output of these handsets. The Nokia 6310i and Audiovox 8300 when in digital
mode will output 0.2 Watts.
When the Analog Motorola StarTac is operating it is at 0.6 Watts optimal.
When and IF the Audiovox 8300 is in analog mode it will operate at 0.6 Watts
(However, this is not normally the case - you will see wattage levels around
0.52 - 0.45 approximately)
Frequency
Both the Telus Mike (C1) and Motorola StarTac (C2) operate in the 800 MHz range.
This will allow the signal to travel at a great distance. However, the IDEN
(Mike) network has fewer site locations and is a newer Digital network. Most
digital technologies operate on a "all or none" basis. When it has
signal it will work well. As the signal fades, one hears no static, but some
digital distortion just before the call drops.
Networks
Mike Network: Newer, all-digital network with modern antenna design, and fewer
cellsites
Bell Mobility Analog: Older, analog network with less focused antenna design
but many cellsites
Telus PCS: Newer, digital network with multiple frequencies, modern antenna
design, and many cellsites
Rogers GSM: Our newest digital network with modern antenna design and many
cellsites
A. K. Dewdney,
February 25th 2003
From Here. Also see: Ghost Riders in the Sky.