iPhone in a glider?

In article writes:
On Sep 18, 8:59 am, Michael Ash wrote:
Matt Herron Jr. wrote:
Has anyone thought about applications for the iPhone 3G platform in a
glider? It has an excellent sunlight readable screen with touch
interface that causes no loss of image quality. It has an
accelerometer built in, a GPS that is probably better than spot,
wireless for speech commands, remote interfaces, etc. fast processor,
lots of ram for large maps and gesture recognition for panning,
zooming, etc. Web access (where available) for a quick weather update
before launch. Seems like an opportunity waiting to happen...

Come up with some good ideas, and maybe I will implement one!

(trimmed)

Unfortunately Apple has some heavy restrictions on what you can do with
the platform, including one that says "Applications may not be designed or
marketed for real time route guidance". I don't know if that would cover
this sort of software or not. From what I hear it's extremely difficult to
get a definitive answer about these things out of Apple without simply
building the app and trying to get it approved. It is possible to work
around these limitations and bypass Apple for distribution, but it tends
to be more work and limit your audience, making it kind of risky.

Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

I just took my new 3G for a flight. gpstracker application works very
well to track flights on google earth. Also gives Long/Lat speed as
well as altitude every 5 seconds. Check it out.


It might be fun, but it is also quite illegal.


47 cfr 22.925 states:

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.


The FAA prohibits the use in flight in 91.21, but that generally doesn't
apply to VFR flight in small aircraft. (It essentially forbids use in airliners
and IFR flight.)

The FCC prohibits use in any aircraft when airborne.

The iPhone is being "operated" when it is updating map data. It is even
being operated when it is turned on and talking to cell towers.

To be legal, turn it off, or put it in airplane mode, before takeoff ---
and leave it that way until back on the ground.

Better to save the battery to make a call if you land out.


Alan

On Sep 19, 5:19*pm, (Alan) wrote:
In article writes:
* The FAA prohibits the use in flight in 91.21, but that generally doesn't
apply to VFR flight in small aircraft. *(It essentially forbids use in airliners
and IFR flight.)

* The FCC prohibits use in any aircraft when airborne.

* The iPhone is being "operated" when it is updating map data. *It is even
being operated when it is turned on and talking to cell towers.

Yeah, and no one in a small place ever broke that one.

But it doesn't matter. Any specialized gliding program can easily be
written to preload the relevant maps before takeoff. You do have 8 GB
or 16 GB of storage for such things. That's the equivalent of 10 - 20
CDs of data.


* To be legal, turn it off, or put it in airplane mode, before takeoff ---
and leave it that way until back on the ground.

The GPS and accelerometer and so forth will work just fine in airplane
mode. Unfortunately they both turn off if the screen turns off (by
hitting the button on the top, or after a timeout if you haven't
disabled it).


* Better to save the battery to make a call if you land out.

Operating the GPS continuously eats the battery. Any serious gliding
application will want to run the iPhone off the glider's battery in
any case.

Alan wrote:
I just took my new 3G for a flight. gpstracker application works very
well to track flights on google earth. Also gives Long/Lat speed as
well as altitude every 5 seconds. Check it out.


It might be fun, but it is also quite illegal.


47 cfr 22.925 states:

22.925 Prohibition on airborne operation of cellular telephones.
[snip]

Aside from the use of "airplane mode", I seem to recall a discussion about
this a while ago wherein it was concluded that modern mobile phones don't
meet the FCC's definition of a "cell phone". The reasoning behind this
regulation is that using a cell phone in flight plays merry havoc with the
cell network due to seeing towers farther away than the network is
designed for. But modern networks work differently and are immune to this
problem, and I *think* the conclusion was that the regulation does not
apply to them.

Anyone know more about it? I'd like to know more than my patchwork
memory....

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

On Fri, 19 Sep 2008 10:25:42 -0500, Michael Ash wrote:


Anyone know more about it? I'd like to know more than my patchwork
memory....

In the UK, anyway, the base station transmission patterns are quite flat
which can stop you getting a signal in the air.

A year or two back I wanted to annoy a friend with the "ring him and hold
phone by the audio vario" trick, but at 3000ft over Huntingdon, i.e.
above a flat bit of Cambridgeshire, there was no signal at all. I was
using a GSM phone, so the radiation pattern was evidently flat enough the
exclude not only Huntingdon masts but also those further away (Cambridge,
Northampton). This makes sense to me. Why should a telco waste
electricity transmitting a hemispherical pattern when a pancake pattern
will give a better signal strength for less radiated power throughout its
service area.

IIRC this has been noticed and commented on in the USA too.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

"Martin Gregorie" wrote in message
...
On Fri, 19 Sep 2008 10:25:42 -0500, Michael Ash wrote:


Anyone know more about it? I'd like to know more than my patchwork
memory....

In the UK, anyway, the base station transmission patterns are quite flat
which can stop you getting a signal in the air.

A year or two back I wanted to annoy a friend with the "ring him and hold
phone by the audio vario" trick, but at 3000ft over Huntingdon, i.e.
above a flat bit of Cambridgeshire, there was no signal at all. I was
using a GSM phone, so the radiation pattern was evidently flat enough the
exclude not only Huntingdon masts but also those further away (Cambridge,
Northampton). This makes sense to me. Why should a telco waste
electricity transmitting a hemispherical pattern when a pancake pattern
will give a better signal strength for less radiated power throughout its
service area.

IIRC this has been noticed and commented on in the USA too.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

My experience with Verizon in the US is that it usually works fine from a
glider.

I used it once to call a tower after my radio failed - but they didn't
answer. They later told me that they couldn't take time to answer the
ringing phone, "because there was some guy in a glider with an inoperative
radio" they had to deal with. Instead they just shot me a green light and I
landed.

In article Martin Gregorie writes:
On Fri, 19 Sep 2008 10:25:42 -0500, Michael Ash wrote:


Anyone know more about it? I'd like to know more than my patchwork
memory....

In the UK, anyway, the base station transmission patterns are quite flat
which can stop you getting a signal in the air.

A year or two back I wanted to annoy a friend with the "ring him and hold
phone by the audio vario" trick, but at 3000ft over Huntingdon, i.e.
above a flat bit of Cambridgeshire, there was no signal at all. I was
using a GSM phone, so the radiation pattern was evidently flat enough the
exclude not only Huntingdon masts but also those further away (Cambridge,
Northampton). This makes sense to me. Why should a telco waste
electricity transmitting a hemispherical pattern when a pancake pattern
will give a better signal strength for less radiated power throughout its
service area.


Interesting. Generally, the attenuation possible from an antenna depends
on the angle of elevation, and if you are 5 miles from the tower, at 3000
feet, you would be 6.5 degrees of elevation above horizontal, which should
be well within the pattern of the antenna. (Any reduction would be easily
made up by the very clear path to the tower.)

I have noticed the same effect on top of mountains here -- at 2600 feet
elevation, looking out at the populated areas, there is no signal.
HOWEVER --- If I walk away and hide behind a building, I get nice strong
signal.

There are a limited number of channels where the cell system
transmits control information. When the phone is not on a call, it
listens to one of them. Each cell site (tower) has one (or perhaps
more) channel for this control information. Like cell calls, it is not
re-used until a "safe" distance away.

When on top of a mountain, there are dozens of towers within sight.
Unfortunately, every available channel is in use by several of these
towers. Thus, the phone cannot receive a clear control signal on any
of the control channels -- each is a jumbled mess of several sites
transmitters.

Much the same happens in the glider.

Hiding behind the building, a few feet back from the edge of the
mountaintop blocks many of these signals. The phone found a good one,
and used it.


IIRC this has been noticed and commented on in the USA too.

And I strongly believe that the signal pattern of the antennas is not
the cause of the problem, or stepping a bit behind the building would not
have made the phone work, as the pattern would have been the same.


Alan

Alan wrote:

A year or two back I wanted to annoy a friend with the "ring him and hold
phone by the audio vario" trick, but at 3000ft over Huntingdon, i.e.
above a flat bit of Cambridgeshire, there was no signal at all. I was
using a GSM phone, so the radiation pattern was evidently flat enough the
exclude not only Huntingdon masts but also those further away (Cambridge,
Northampton). This makes sense to me. Why should a telco waste
electricity transmitting a hemispherical pattern when a pancake pattern
will give a better signal strength for less radiated power throughout its
service area.


Interesting. Generally, the attenuation possible from an antenna depends
on the angle of elevation, and if you are 5 miles from the tower, at 3000
feet, you would be 6.5 degrees of elevation above horizontal, which should
be well within the pattern of the antenna. (Any reduction would be easily
made up by the very clear path to the tower.)

More phones means the cells have to be smaller. Many/most of towers
around here have a number of what appear to be VERY directional
antennas, and the towers are low ( 100'), and surely very low power,
because the next tower is only a mile or two away. They aren't going to
reach out to 5 miles, even under the best of conditions. The loss of
signal at 3000' or so is common where the cells a small, such as near
cities. The rural areas often work to higher altitudes, if they have
coverage in the area.

My old analog/TDMA phone used to work very well to even 15000' agl, but
my new TMobile GSM phone is unreliable off the ground, and worthless at
our 7000-9000 agl soaring altitudes, even in our mostly rural Eastern
Washington.

I suspect there is a lot of variation between providers; even so, I
think it's just going to get worse as the cells get smaller yet.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

In article %K%Ak.553$8v5.378@trnddc01 Eric Greenwell writes:

More phones means the cells have to be smaller. Many/most of towers
around here have a number of what appear to be VERY directional
antennas, and the towers are low ( 100'), and surely very low power,
because the next tower is only a mile or two away. They aren't going to
reach out to 5 miles, even under the best of conditions.

On the ground, where there are obstacles, that is true. To an
airborne receiver, the range is much farther.

Don't be sure about that low power -- the directional antennas have
a fair amount of gain. The FCC allows 500 watts per channel of effective
radiated power, but 100 watts is a more common figure. (See:
http://www.fcc.gov/cgb/consumerfacts/rfexposure.html ).

Even a very small amount of power to them will provide far more than
5 miles range.

In fact, one of the noted problems of GSM is that the timing of the
system is the timing induced range limit of about 25 miles, but an
extended variant increases this substantially. Fishermen off the coast
of the U.S. use cell phones out well past 25 miles.

I have used cellphones over 8 miles offshore, and apparently glider
pilots carry them in case of land outs in some pretty remote areas.


Alan
wa6azp

Alan wrote:
In article %K%Ak.553$8v5.378@trnddc01 Eric Greenwell
writes:

More phones means the cells have to be smaller. Many/most of towers
around here have a number of what appear to be VERY directional
antennas, and the towers are low ( 100'), and surely very low
power, because the next tower is only a mile or two away. They
aren't going to reach out to 5 miles, even under the best of
conditions.

On the ground, where there are obstacles, that is true. To an
airborne receiver, the range is much farther.

And yet, I can have good service on the ground, but poor or no service
in the air, over the same area. It's not about obstacles, but antenna
patterns, power, and how the system handles a phone that is reaching
multiple towers.


Don't be sure about that low power -- the directional antennas have a
fair amount of gain. The FCC allows 500 watts per channel of
effective radiated power, but 100 watts is a more common figure.
(See: http://www.fcc.gov/cgb/consumerfacts/rfexposure.html ).

From the article:

"the majority of cellular or PCS cell sites in urban and suburban areas
operate at an ERP of 100 watts per channel or less".

The "or less" is important, as a small cell doesn't require much power.
The ERP is obtained with directional antennas, so while it might seem
high, the vertical angle coverage is very shallow. A cell set up for an
Interstate highway will have to use much more power as the cells are
farther apart, and the pattern might be broader, so aircraft near a
highway might experience better reception.


Even a very small amount of power to them will provide far more than
5 miles range.

In fact, one of the noted problems of GSM is that the timing of the
system is the timing induced range limit of about 25 miles, but an
extended variant increases this substantially. Fishermen off the
coast of the U.S. use cell phones out well past 25 miles.

And maybe a cell phone used in the air in those areas would work well.
It's not a place glider pilots have much experience with! THe coast is a
different situation than a inhabited area, and I'm guessing the antenna
power and pattern are likely quite different because of that.

I have used cellphones over 8 miles offshore, and apparently glider
pilots carry them in case of land outs in some pretty remote areas.

And with the full expectation that it will be pure luck if it works; for
example, my phone does not work on sections of major highways in Nevada,
so expecting to work in most areas off the highway is unwise. That is
why the SPOT device is becoming so popular, along with PLBs, in addition
to the usual ELTs and aviation radios. Also, pilots try to radio their
position while in air before landing, because they know using a cell
phone or aircraft radio on the ground is going to be unreliable.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly

* Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4
* New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more

* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

On Sep 19, 8:25*am, Michael Ash wrote:
Alan wrote:
I just took my new 3G for a flight. gpstracker application works very
well to track flights on google earth. Also gives Long/Lat speed as
well as altitude every 5 seconds. Check it out.

*It might be fun, but it is also quite illegal.

*47 cfr 22.925 states:

* * 22.925 * Prohibition on airborne operation of cellular telephones.

[snip]

Aside from the use of "airplane mode", I seem to recall a discussion about
this a while ago wherein it was concluded that modern mobile phones don't
meet the FCC's definition of a "cell phone". The reasoning behind this
regulation is that using a cell phone in flight plays merry havoc with the
cell network due to seeing towers farther away than the network is
designed for. But modern networks work differently and are immune to this
problem, and I *think* the conclusion was that the regulation does not
apply to them.

Anyone know more about it? I'd like to know more than my patchwork
memory....

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon


As pilot in command of a non-IFR flight I grant myself permission to
use all kinds of electronic toys in flight. So that gets rid of FAA
concerns. However my belief is that 47 CFR. 22.925 does apply to the
iPhone since it is quad-band GSM that uses the GSM 850MHz band in the
USA. If you have say a different brand PCS phone that exclusively uses
1800MHz then this would not apply to you.

There is a wiki entry about this at http://en.wikipedia.org/wiki/Mobile_phones_on_aircraft

In reality I turn my phone off to save battery life and distractions
like the phone ringing while I'm on final (it's happened).

So would I really want some new soaring software running on an iPhone?
Sure I could see lots of neat UI things that could be done (Cocoa is a
lovely UI to develop for) and the platform is powerful etc. The screen
is a bit more visible in sunlight than most PDA screens, but it is
still not really great. The downside of that is I'm set in my ways
with SeeYou, so if Naviter wanted to port across SeeYou keeping some
of it's core behavior/feature but offering an updated Cocoa UI/feel
then I might be interested. Except for a few issues...

I'm not going to use anything that does not talk to an external flight
computer, e.g. for extended NEMA sentences for improved wind
calculations etc. and I want to be sure my IGC logger is working OK so
getting the GPS from it is a way to test this. Also I really don't
want to mess with my iPhone as the display device in my glider, it's
my phone that gets messed with a lot. But I'd be happy to dedicate an
iPod Touch to this - in which case since it has no GPS you really need
an external interface. Unfortunately the iPhone SDK does not give
access to the serial port, and even if you had access to the serial
port you will need some RS-232 line driver hardware to shift voltages
to interface with a real RS-232 serial port in the GPS. The fact that
Apple did not include that in the iPhone makes me think they really
don't want to expose the serial port. The iPhone has bluetooth but
does not support a serial profile, so you can't connect to a
bluetooth GPS, or try to run a serial-bluetooth convertor on a flight
computer serial port etc. over bluetooth. And it's just a USB slave
(like a PDA) so you can't use a USB to serial translator. Then there
is the issue of no way to use a CF or SD card or USB dongle etc. for
flight log transfers and there is no third party code to run on it to
download flight traces from loggers etc. Sure something like ConnectMe
could be ported over (oops if there was just access to that danged
serial port), oh and opps there is no file management UI in the iPhone
so doing things nice and easily with log files etc. will be clumsier
than it should). You could use or implement something like FileMagnet
or DataCase and transfer log files over WiFi (of course that requires
a WiFi setup), or email the file, otherwise you are going to stuck
emailing file attachments or having to sync the iPhone to get off any
log files.

As it currently stands Apple's iPhone SDK license agreement has the
restrictions mentioned already in this thread "Applications may not be
designed or marketed for real time route guidance; automatic or
autonomous control of vehicles, aircraft, or ..." (it is the real time
route guidance that likely gets us, the "aircraft" stuff is irrelevant
since we are not talking about an automatic or autonomous control".
This restriction is in the SDK agreement, not just the iTunes store,
so the only way around this is to use a non-Apple SDK with a jail
broken phone. Then you are (questionably) violating other agreements.
For anybody to put serious effort into developing such software, even
if they wanted to open source it or give away binaries I doubt there
is a significant enough "market" in jail broken 3G iPhones and their
owners who want to put up with this. And while distributing through
the AppStore is neat, it has some serious pain in the ass issues for
higher end applications, starting with customer support say worthy of
0.99c applications. If somebody was serious and could get around the
serial I/O and other issues then they could try talking to Apple, they
might agree to modify route guidance restriction for a specific
application (but don't hold your breath).


Darryl