iPhone in a glider? [Archive]

Michael Ash

September 18th 08, 04:59 PM

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!

It's something I've given some thought to. I don't have an iPhone and
don't want to pay for the expensive subscription, so I was hoping that the
second version of the iPod Touch would include GPS. Unfortunately it
didn't, so the iPhone is still the only one with that.

As for functionality, seems like it would be great to have a moving map,
glide amoeba, thermal finder, and any other goodies that could be stuffed
in there. I agree that it packs a great deal of power and would be a very
capable machine.

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

[email protected]

September 19th 08, 04:37 AM

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!
>
> It's something I've given some thought to. I don't have an iPhone and
> don't want to pay for the expensive subscription, so I was hoping that the
> second version of the iPod Touch would include GPS. Unfortunately it
> didn't, so the iPhone is still the only one with that.
>
> As for functionality, seems like it would be great to have a moving map,
> glide amoeba, thermal finder, and any other goodies that could be stuffed
> in there. I agree that it packs a great deal of power and would be a very
> capable machine.
>
> 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.

Alan[_6_]

September 19th 08, 06:19 AM

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

Bruce Hoult

September 19th 08, 09:17 AM

On Sep 19, 3:59*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...

I agree, it's a great platform for such an explanation. I've used and
have been programming an iPhone since November. I'm lead programmer
on a product that allows people to write Java programs and compile
them to native code or the iPhone (and also for BREW and Windows
Mobile).

> It's something I've given some thought to. I don't have an iPhone and
> don't want to pay for the expensive subscription, so I was hoping that the
> second version of the iPod Touch would include GPS. Unfortunately it
> didn't, so the iPhone is still the only one with that.

I guess it varies from country to country but here in NZ Vodafone have
recently introduced a plan for $40/month (US$27) -- of which nearly
$12 is effectively paying back the $280 subsidy in the $699 purchase
price on an 8 GB iPhone. Or you can pay the full $979 up front and
use it on prepay, which costs you nothing if you don't use the phone.
Data on prepay costs $1 for anything between 200 KB and 10 MB on a
given a calendar day, or 0.5c/KB if you use less than 200 KB. (and $1
a MB if you go past 10 MB :-( )

> As for functionality, seems like it would be great to have a moving map,
> glide amoeba, thermal finder, and any other goodies that could be stuffed
> in there. I agree that it packs a great deal of power and would be a very
> capable machine.

To give people an idea what it can do, it's got very much the same
CPU, RAM and disk (flash) specifications as a high end laptop computer
from around 2000 e.g. the "Pismo" G3 PowerBook, or a 2nd generation
iMac DV (the ones that got FireWire and a DVD drive). The main
exception is that the screen is 20% of the size (153600 pixels vs
786432), but against that the 3D hardware is much better -- I grabbed
the X-Plane version a few days ago and it's very smooth.

> 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.

It's a bit restrictive if you want to put the program into the
AppStore, yes. I believe that the turn by turn guidance restriction
is purely due to licensing terms for the street maps, and possibly
some liability reasons if you go the wrong way down a one-way street.
If there is any justice then that would not apply to an aviation
application.

For such a specialized application I don't know if getting into the
AppStore is such a big thing. It does simplify the "getting paid"
problem hugely, especially for very cheap programs where transaction
costs would normally kill you, but as the market will be small I don't
think you're going to see a soaring application from anyone for $1 or
$2.

Other distribution mechanisms:

- via Cydia. No restrictions at all, but users have to be prepared to
run Pwnage to "jailbreak" their phones. It's easy, but does
potentially void your warranty. (but if there are any problems it's
99.999% likely that restoring the original software will leave no
traces of naughtiness). And developers have to find a way to get paid
and operate their own store, exactly the same as for every non-iPhone
platform.

- via Apple's "ad hoc" distribution mechanism. A developer can
collect up to 100 iPhone serial numbers from other people and directly
send them a working program that they can install locally via iTunes
(on Mac or Windows). This is intended for beta testing or use in
something like a school.

- anyone who pays Apple's $99 fee (and has a Mac) can become a
developer and compile and install any and as many programs as they
want. That's fine for Open Source programs. It's also easily
possible to distribute 99% of such as program to others as a compiled
library that they can't easily reverse engineer or alter.

In short: the logistics and costs of selling and distributing a
program for the iPhone are similar to any other existing mobile
device. Except if you can get it into the AppStore, in which case it
is uniquely cheap, easy, and convenient for both buyer and seller.

Bruce Hoult

September 19th 08, 09:27 AM

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.

Michael Ash

September 19th 08, 04:25 PM

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

Michael Ash

September 19th 08, 04:34 PM

Bruce Hoult > wrote:
> On Sep 19, 3:59?am, Michael Ash > wrote:
>> It's something I've given some thought to. I don't have an iPhone and
>> don't want to pay for the expensive subscription, so I was hoping that the
>> second version of the iPod Touch would include GPS. Unfortunately it
>> didn't, so the iPhone is still the only one with that.
>
> I guess it varies from country to country but here in NZ Vodafone have
> recently introduced a plan for $40/month (US$27) -- of which nearly
> $12 is effectively paying back the $280 subsidy in the $699 purchase
> price on an 8 GB iPhone. Or you can pay the full $979 up front and
> use it on prepay, which costs you nothing if you don't use the phone.
> Data on prepay costs $1 for anything between 200 KB and 10 MB on a
> given a calendar day, or 0.5c/KB if you use less than 200 KB. (and $1
> a MB if you go past 10 MB :-( )

In the US the only option is with a 2-year subscription starting at
$70/month, not including taxes, which push the minimum bill up near
$80/month. My current subscription is about $45/month after taxes and I'm
looking at ways to reduce even that, as I don't make that many calls.

>> 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.
>
> It's a bit restrictive if you want to put the program into the
> AppStore, yes. I believe that the turn by turn guidance restriction
> is purely due to licensing terms for the street maps, and possibly
> some liability reasons if you go the wrong way down a one-way street.
> If there is any justice then that would not apply to an aviation
> application.

Yes, but we're talking about Apple here.... :)

The main problem is the risk. It *shouldn't* apply to an aviation
application, but the only way to really find out is to actually build the
app, submit it, and see if they let it through. If they don't, that's a
lot of work potentially lost.

> For such a specialized application I don't know if getting into the
> AppStore is such a big thing. It does simplify the "getting paid"
> problem hugely, especially for very cheap programs where transaction
> costs would normally kill you, but as the market will be small I don't
> think you're going to see a soaring application from anyone for $1 or
> $2.
>
> Other distribution mechanisms:
[snip]

I agree, for the price that you're likely to be charging for such a
program, bypassing Apple altogether would become worthwhile. The trouble
is that there's always a risk that Apple will shut these mechanisms down,
but the smart money always goes with the hackers in this kind of contest,
so it's probably not a significant worry.

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

John Smith

September 19th 08, 05:02 PM

Alan wrote:

> It might be fun, but it is also quite illegal.
>
> 47 cfr 22.925 states:

What the hell is 47 cfr 22.925???

> The FAA prohibits the use in flight

And what the hell is FAA???

Oh, I see! You've just forgotten that there's life outside the USA.

Martin Gregorie[_4_]

September 19th 08, 07:13 PM

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 |

Bill Daniels

September 19th 08, 08:34 PM

"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.

Darryl Ramm

September 19th 08, 09:13 PM

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

Tony Verhulst

September 19th 08, 11:24 PM

> 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).

I do now. I was on short final when my wife decided to call me. My
student did a double take and said "what the f...?". The name of my ring
tone is "vario rising".

Tony V.

September 20th 08, 12:59 AM

On Sep 18, 1:32*am, "Matt Herron Jr." > wrote:
> Come up with some good ideas, and maybe I will implement one!

How about porting GlidePlan? Or a nice user friendly sectional chart
viewer?

Unless someone comes up with moving map software that can display
CURRENT sectional chart information, I'll still need to carry paper
charts.

What I do now, is use GlidePlan to print up a 60% 'booklet' of the
charts I plan to fly with. I forget the actual percent shrinkage, but
it's just small enough so one side of the chart fits on a portrait
sized 8.5x11 sheet of paper. I then use 20% page overlap, so I'm
always looking near the middle of a page. The text is pretty small,
but still just barely legible so I can pick up any needed frequencies,
etc.

The viewer program should provide pan and zoom functionality as well
as an automated switch to the next chart as one scrolls off the edge.
It should use the GPS to select the right chart, as well as have a
database of airports & cities, so I could enter such and the proper
chart will be displayed and centered on that location.

-Tom
Who has ATT service with a 5 month old Samsung BlackJack that's way
too dim to use for color apps in sunlight.

Bruce Hoult

September 20th 08, 01:53 AM

On Sep 20, 3:34*am, Michael Ash > wrote:
> Bruce Hoult > wrote:
> The main problem is the risk. It *shouldn't* apply to an aviation
> application, but the only way to really find out is to actually build the
> app, submit it, and see if they let it through. If they don't, that's a
> lot of work potentially lost.

Not lost. If you make your plans based on surviving using
distribution independent of Apple then you can submit to the AppStore
and see what happens. If you get in then bonus.

The PodCaster guys are reportedly doing brisk business despite not
being in the AppStore.

Darryl Ramm

September 20th 08, 03:55 AM

On Sep 19, 5:53*pm, Bruce Hoult > wrote:
> On Sep 20, 3:34*am, Michael Ash > wrote:
>
> > Bruce Hoult > wrote:
> > The main problem is the risk. It *shouldn't* apply to an aviation
> > application, but the only way to really find out is to actually build the
> > app, submit it, and see if they let it through. If they don't, that's a
> > lot of work potentially lost.
>
> Not lost. *If you make your plans based on surviving using
> distribution independent of Apple then you can submit to the AppStore
> and see what happens. *If you get in then bonus.
>
> The PodCaster guys are reportedly doing brisk business despite not
> being in the AppStore.

The Podcaster guys sell a ~$10 application that Apple can apparently
turn off at any time. The logic why they don't just submit through the
iTunes store is questionable. This is not just an issue if you want to
distribute through the store, it's a base restriction in the SDK.
Anybody wanting to put real effort into doing this is going to want to
sort this out before building the application. Then it's a closed
system and you are always pretty much at Apple's mercy. Which I assume
Bruce is used to thinking about - since if his product is doing Java
compilation then unless you've got a deal with Apple that software is
going to run up against the "other executable code"/interpreted
languages restriction in the SDK agreement...

....Just to hammer this to death I disagree that the comment that the
ecosystem of distributing apps for the iPhone is like other mobile
device. The iPhone is designed to be a closed system. But hey it's a
very pretty closed system. The App store infrastructure is nice for
low margin micro-applications (and why others like Microsoft are
running to catch up) but has more issues for serious applications.
Like the software vendors inability to very rapidly patch things,
Apple being able to make fairly arbitrary decisions, etc. etc.

But again, I'd claim there are practical restrictions today that
probably are showstoppers for a serious application... no I/O over
serial port, bluetooth or USB, no CF/SD card, no file system/file
UI, ... Of all these I'd hope that Apple would add a serial profile to
bluetooth and a (limited) filesystem like UI in future.

Darryl

Michael Ash

September 20th 08, 04:14 AM

Bruce Hoult > wrote:
> On Sep 20, 3:34?am, Michael Ash > wrote:
>> Bruce Hoult > wrote:
>> The main problem is the risk. It *shouldn't* apply to an aviation
>> application, but the only way to really find out is to actually build the
>> app, submit it, and see if they let it through. If they don't, that's a
>> lot of work potentially lost.
>
> Not lost. If you make your plans based on surviving using
> distribution independent of Apple then you can submit to the AppStore
> and see what happens. If you get in then bonus.

Well, that's why I said "potentially", since the end result depends on
your planning and your market. For a small, cheap app you really lose out,
but a more specialized expensive app is in a better position to use
alternative venues.

> The PodCaster guys are reportedly doing brisk business despite not
> being in the AppStore.

Not sure how it compares to being in the official store, though,
particularly in the long run. And it's a *lot* more work for them the way
they're currently doing it. Every customer has to be manually added
through Apple's rather cumbersome tools (because they're not meant for
this) and this may have to be re-done for every update they release, I'm
not sure on that point. However this is considerably less of an issue for
specialist soaring software.

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

Michael Ash

September 20th 08, 04:16 AM

Darryl Ramm > wrote:
> The Podcaster guys sell a ~$10 application that Apple can apparently
> turn off at any time. The logic why they don't just submit through the
> iTunes store is questionable.

Perhaps I'm misunderstanding you, but they did submit through the store
and were rejected, and for rather questionable reasons.

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

Darryl Ramm

September 20th 08, 04:46 AM

On Sep 19, 8:16*pm, Michael Ash > wrote:
> Darryl Ramm > wrote:
> > The Podcaster guys sell a ~$10 application that Apple can apparently
> > turn off at any time. The logic why they don't just submit through the
> > iTunes store is questionable.
>
> Perhaps I'm misunderstanding you, but they did submit through the store
> and were rejected, and for rather questionable reasons.
>
> --
> Mike Ash
> Radio Free Earth
> Broadcasting from our climate-controlled studios deep inside the Moon

Oops, sorry your completely correct, I had a brain fade. Yes Apple
trying to protect the iTunes WiFi store podcast downloads they don't
support!

Darryl

Darryl

Alan[_6_]

September 20th 08, 05:07 AM

In article > Darryl Ramm > writes:

>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.

Sounds good. It has long worked for me, too.

> 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.

Perhaps not, because some call those PCS instead of cellphones, but I don't
know what the FCC's reaction would be. I would not want to be explaining it
when they are pointing out some definition in another part of the rules that
says cell phone covers both...

>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.

How true. A well integrated system could reduce pilot workload and increase
safety. The iPhone is cute, and a system one could use on the ground to play
with would be fun, but it really doesn't fit well into a fully integrated flight
and nav computer.

Alan

Alan[_6_]

September 20th 08, 05:10 AM

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[_6_]

September 20th 08, 05:12 AM

In article > John Smith > writes:
>Alan wrote:
>
>> It might be fun, but it is also quite illegal.
>>
>> 47 cfr 22.925 states:
>
>What the hell is 47 cfr 22.925???
>
>> The FAA prohibits the use in flight
>
>And what the hell is FAA???
>
>Oh, I see! You've just forgotten that there's life outside the USA.

No, I just quoted the rules where I am, and where a large number of
the participants are.

I did, however, forget for a moment that the iPhone is now available
out there, too.

Now, if you can tell where *you* are, and provide the links to the
regulations there, we can check if it is legal there.

Alan

Darryl Ramm

September 20th 08, 06:05 AM

On Sep 19, 9:07*pm, (Alan) wrote:
> In article > Darryl Ramm > writes:
>
> >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.
>
> * Sounds good. *It has long worked for me, too.
>
> > 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.
>
> * Perhaps not, because some call those PCS instead of cellphones, but I don't
> know what the FCC's reaction would be. *I would not want to be explaining it
> when they are pointing out some definition in another part of the rules that
> says cell phone covers both...
>

The legal issue as I read it is only with "cellphones" that use the
800MHz spectrum - it is devices using this spectrum that is
specifically called out in the regulations. That is the only thing
covered by the FCC regulations we are talking about. I fully expect
the FCC to understand the difference say between GSM850 vs PCS1800.
But PCS in general, and especially factoring USA coverage, is much
less useful to try to use from the air. And when was the last time
anybody saw an FCC investigator hanging around the airport.

To me, cellphones don't work well enough in the air to hassle with and
can be distracting, so unless I really need to try to make a call I
keep it turned off. Which keeps the battery charged for when I might
need it after landing should I be lucky enough to have reception.

Darryl

Eric Greenwell

September 20th 08, 06:20 AM

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

Alan[_6_]

September 20th 08, 07:21 AM

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

Darryl Ramm

September 20th 08, 07:24 AM

On Sep 18, 12:32*am, "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!
>
> Matt Herron
> GlidePlan Inc.http://www.glideplan.com

I've already complained about lack of any way to communicate with an
external GPS but I'm enjoying this so lets bash this a bit more.

I'm not sure what a SPOT satellite messenger and a 3G iPhone GPS have
to do with each other but lets tackle that anyhow... The GPS in the
iPhone 3G is an Infineon PMB2525 Hammerhead II GPS with a really small
antenna (see http://blogs.zdnet.com/hardware/?p=2261&page=2). The
antenna will be facing the pilot if in a usual PDA type cradle, gee it
might work but it is not a good place for high quality GPS reception
in a glider.

The SPOT Messenger uses a - Nemerix NX2 GPS Chipset (maybe they've
upgraded to the NX3?) with a larger GPS antenna than the iPhone, and
it's antenna is on the top of the device so if placed as intended the
antenna will have a good view of the sky. Both chipsets are similar
and both are aimed at the same market of intelligent devices like
cellphones requiring low power consumption, both chipsets are amazing
for what they can do. So I'd disagree with the comment on the iPhone
GPS being better the SPOT. Not that the comparison is relevent. A
modern GPS receiver that I'd want to use in an aircraft for navigation
purposes with a traditional large antenna correctly oriented to the
sky should do much better than the iPhone GPS, but I'll point out that
many flight computers etc. are doing fine using very old GPS engines,
but it's the antenna location/orientation that can be really
important.

Then there is the CoreLocation API that the iPhone SDK exposes. I'd
not want to try to develop an aviation navigation package on top of
the rudimentary services it exposes. OK so you can get basic info
including altitude, but that's it. Want to look at any low level
settings or status like how many satellites are in view in, etc. you
are SOL. Oh yes and that pesky iPhone SDK agreement prohibits hacking
into any lower level (GPS) interfaces. And there is the supposed
blacklist/killswitch inside the CoreLocation API that allows Apple to
shut off acces to applications using that service they don't like. Try
to use this to navigate an aircraft (if they don't like the route
guidance part), try to bypass the App Store, they might still be able
to get you with the CoreLocation kill switch. So seems if you want to
go that far you might as well jailbreak the phone.

And I think somebody already mentioned that the internal GPS is turned
off when the phone is in Airplane mode. So you'll need to leave the
GSM phone on, violating that FCC rule, but more importantly sucking
power and putting out heat. So you'll definitely need to power the
iPhone from the ship's battery. I have no problem with that but wonder
how hot the iPhone will get in direct sunlight in a hot cockpit and
whether it will handle this any better than the two iPAQ 4700 I own
that suck when they get hot.

So where does that leave us? As I see it the iPhone is pretty piece of
jewelry that as it stands today is unlikely to be useful for a soaring
navigation/display unless you want to jailbreak and hack the phone and
I just don't see the effort/reward there. It is however a damn nice
iPod to take along on flights and handy for finding the nearest
steakhouse for that tired ground crew.

Darryl

Jeffrey \PT\ Smith

September 20th 08, 07:34 AM

Darryl Ramm

September 20th 08, 07:37 AM

On Sep 19, 11:24*pm, Darryl Ramm > wrote:
> On Sep 18, 12:32*am, "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!
>
> > Matt Herron
> > GlidePlan Inc.http://www.glideplan.com
>
> I've already complained about lack of any way to communicate with an
> external GPS but I'm enjoying this so lets bash this a bit more.
>
> I'm not sure what a SPOT satellite messenger and a 3G iPhone GPS have
> to do with each other but lets tackle that anyhow... The GPS in the
> iPhone 3G is an Infineon PMB2525 Hammerhead II GPS with a really small
> antenna (seehttp://blogs.zdnet.com/hardware/?p=2261&page=2). The
> antenna will be facing the pilot if in a usual PDA type cradle, gee it
> might work but it is not a good place for high quality GPS reception
> in a glider.
>
> The SPOT Messenger uses a - Nemerix NX2 GPS Chipset (maybe they've
> upgraded to the NX3?) with a larger GPS antenna than the iPhone, and
> it's antenna is on the top of the device so if placed as intended the
> antenna will have a good view of the sky. *Both chipsets are similar
> and both are aimed at the same market of intelligent devices like
> cellphones requiring low power consumption, both chipsets are amazing
> for what they can do. So I'd disagree with the comment on the iPhone
> GPS being better the SPOT. Not that the comparison is relevent. A
> modern GPS receiver that I'd want to use in an aircraft for navigation
> purposes with a traditional large antenna correctly oriented to the
> sky should do much better than the iPhone GPS, but I'll point out that
> many flight computers etc. are doing fine using very old GPS engines,
> but it's the antenna location/orientation that can be really
> important.
>
> Then there is the CoreLocation API that the iPhone SDK exposes. I'd
> not want to try to develop an aviation navigation package on top of
> the rudimentary services it exposes. OK so you can get basic info
> including altitude, but that's it. Want to look at any low level
> settings or status like how many satellites are in view in, etc. you
> are SOL. Oh yes and that pesky iPhone SDK agreement prohibits hacking
> into any lower level (GPS) interfaces. And there is the supposed
> blacklist/killswitch inside the CoreLocation API that allows Apple to
> shut off acces to applications using that service they don't like. Try
> to use this to navigate an aircraft (if they don't like the route
> guidance part), try to bypass the App Store, they might still be able
> to get you with the CoreLocation kill switch. So seems if you want to
> go that far you might as well jailbreak the phone.
>
> And I think somebody already mentioned that the internal GPS is turned
> off when the phone is in Airplane mode. So you'll need to leave the
> GSM phone on, violating that FCC rule, but more importantly sucking
> power and putting out heat. So you'll definitely need to power the
> iPhone from the ship's battery. I have no problem with that but wonder
> how hot the iPhone will get in direct sunlight in a hot cockpit and
> whether it will handle this any better than the two iPAQ 4700 I own
> that suck when they get hot.
>
> So where does that leave us? As I see it the iPhone is pretty piece of
> jewelry that as it stands today is unlikely to be useful for a soaring
> navigation/display unless you want to jailbreak and hack the phone and
> I just don't see the effort/reward there. It is however a damn nice
> iPod to take along on flights and handy for finding the nearest
> steakhouse for that tired ground crew.
>
> Darryl

BTW Matt I meant to end my rant on a positive tone - a perfect iPhone
application example would be an iPhone friendly version of Dr Jack's
BLIPMAPS starting with a minimalistic website laid out for the iPhone
(I'm building my own simplified pages to get to Jack's files), going
through to an iPhone universal BLIPMAP viewer application, complete
with the ability to store (and recall in flight) things like RASP
convergence charts - things that actually are useful in flight. You
could use the crappy internal GPS to locate where you are located
within that viewer and provide track/heading up map orientation - but
you are not using it for primary navigation. I do use the iPhone now
to check RASP blipmaps before flying and the multi-touch interface is
just beautiful compared to tryign to do this on other mobile devices/
PDAs.

Darryl

John Smith

September 20th 08, 09:14 AM

Alan wrote:

> Now, if you can tell where *you* are, and provide the links to the
> regulations there, we can check if it is legal there.

I'm sorry but I can't, because there is no regulation at all here
regarding the use of cell phones in VFR aircraft.

John Smith

September 20th 08, 09:22 AM

BTW, there is GeoPS, a Macintosh application for up and downloading data
from/to a logger. Wouter seems willing to port the app to the iPhone if
there is enough demand.

Have a look at his site and encourage him to do the port!
http://www.human-software.nl/geops/

Eric Greenwell

September 20th 08, 03:32 PM

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

Darryl Ramm

September 20th 08, 05:20 PM

On Sep 20, 1:22*am, John Smith > wrote:
> BTW, there is GeoPS, a Macintosh application for up and downloading data
> from/to a logger. Wouter seems willing to port the app to the iPhone if
> there is enough demand.
>
> Have a look at his site and encourage him to do the port!http://www.human-software.nl/geops/

How will he port this if there is no serial port on the iPhone/iPod
Touch. (unless you want to jail break one and also provide RS-232 line
driver hardware). And you can't use a USB-serial adapter on an iPhone
like you would do on a Mac with this software since it is just a USB
slave.

Darryl

Dan Thirkill

September 21st 08, 02:14 AM

Wow-

Whatever happened to pure flying?

"Matt Herron Jr." > wrote in message
...
> 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!
>
> Matt Herron
> GlidePlan Inc.
> http://www.glideplan.com

Alan[_6_]

September 21st 08, 07:29 AM

In article > Eric Greenwell > writes:
>Alan wrote:
>> 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.

My point exactly.

In the air, your phone hears multiple cell transmitters on each frequency.
It may have difficulty finding a channel where it can clearly hear the
control information.

On the ground, those obstacles limit the number of cell towers your phone
can hear, so it has no trouble finding a clean channel.

>>
>> 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.

However, the vertical angle is not that shallow. Even an antenna with a
half power beamwidth extending up only 5 degrees puts that half power level
above 3000 feet at 7 miles out, a very easy range given the lack of
obstacles.

Directional antennas don't completely cut off outside the half power
beamwidth.

Your explanation also doesn't explain why when the cellphone doesn't work
while standing on the mountain top next to the suburban area, walking behind
a building to shield the phone from the view of so many cell towers causes it
to start working. The angles from the cell towers don't change.

Alan
wa6azp

Alan[_6_]

September 21st 08, 07:30 AM

In article > John Smith > writes:
>Alan wrote:
>
>> Now, if you can tell where *you* are, and provide the links to the
>> regulations there, we can check if it is legal there.
>
>I'm sorry but I can't, because there is no regulation at all here
>regarding the use of cell phones in VFR aircraft.

Do you have regulations concerning radio transmission? Are they online?

Do you have any aircraft regulations? Are they online?

Where are you?

Alan

Eric Greenwell

September 22nd 08, 12:40 AM

Alan wrote:
> In article > Eric Greenwell > writes:

>> 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.
>
> My point exactly.
>
> In the air, your phone hears multiple cell transmitters on each frequency.
> It may have difficulty finding a channel where it can clearly hear the
> control information.

That sounds like a pretty good explanation. Would that explain why the
the signal strength display (number of bars shown) is low or zero? The
lack of bars is what makes me think the power drops off with altitude
enough to stop the phone from working, but maybe that's incorrect.

> Your explanation also doesn't explain why when the cellphone doesn't work
> while standing on the mountain top next to the suburban area, walking behind
> a building to shield the phone from the view of so many cell towers causes it
> to start working. The angles from the cell towers don't change.

I haven't tried that, but it does suggest the phone in the glider should
be shielded so it uses signals in only one direction as a way to improve
it's operation. Tough to do while circling, but maybe it'd be practical
in straight flight.

--
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

Alan[_6_]

September 22nd 08, 06:31 AM

In article > Eric Greenwell > writes:
>Alan wrote:
>> In article > Eric Greenwell > writes:
>
>>> 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.
>>
>> My point exactly.
>>
>> In the air, your phone hears multiple cell transmitters on each frequency.
>> It may have difficulty finding a channel where it can clearly hear the
>> control information.
>
>That sounds like a pretty good explanation. Would that explain why the
>the signal strength display (number of bars shown) is low or zero? The
>lack of bars is what makes me think the power drops off with altitude
>enough to stop the phone from working, but maybe that's incorrect.

You are quite correct that in many cases, this indication is not real signal
strength.

Part of the problem with the count of bars on such devices is that the number
of bars is often derived from a "quality of signal" metric, such as error rate,
rather than the actual signal strength. Apparently that is easier to do in the
software of the phone. As such, interference can lower the number of bars just
as a weak signal can; unfortunately it can be hard to tell which is the problem
with the reception.

The same is true of most digital television receivers or converters. There
they even frequently label it as 'signal strength', when it most definitely
is not.

Another annoying feature of these digital indications is that the result is
fairly slow in updating. This makes it difficult to position a cellphone or
aim a television antenna.

>> Your explanation also doesn't explain why when the cellphone doesn't work
>> while standing on the mountain top next to the suburban area, walking behind
>> a building to shield the phone from the view of so many cell towers causes it
>> to start working. The angles from the cell towers don't change.
>
>I haven't tried that, but it does suggest the phone in the glider should
>be shielded so it uses signals in only one direction as a way to improve
>it's operation. Tough to do while circling, but maybe it'd be practical
>in straight flight.

Well, it would seem tight quarters for manuvering a good shield inside a
fiberglass glider, and using the body of the glider for that would probably
be ineffective. A metal glider might limit downward signals to those that
diffract over the body into the glider, but that could also be hard to
control.

If you can manage to do it, though, I would bet that it would work.

Alan
wa6azp

Eric Greenwell

September 22nd 08, 11:10 PM

Alan wrote:
> In article > Eric Greenwell > writes:
> Well, it would seem tight quarters for manuvering a good shield inside a
> fiberglass glider, and using the body of the glider for that would probably
> be ineffective. A metal glider might limit downward signals to those that
> diffract over the body into the glider, but that could also be hard to
> control.
>
> If you can manage to do it, though, I would bet that it would work.

I'll give it a try next time I fly. In the past, I've held the phone up
high in the cockpit so it good get a good view of the ground, which
worked well with my old analog/TDMA phone, but now that sounds like the
wrong thing to do.

--
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

fredsez

September 23rd 08, 05:58 AM

Alan[_6_]

September 23rd 08, 08:22 AM

In article > fredsez > writes:

>What the hell, there are so many rules and regulations that the rule
>makers are lost. I climb 9,000 ft mountains near a 16 million
>population, and my phone will probably blast them all. I am not in an
>aircraft, so I'm legal, but I might as well be. I fly over the same
>mtns and would like to have the ability to have someone be able to
>track my position by GPS. My granddaughter landed in the big nasty
>mountains and spent the night in "God knew nowhere". She managed a
>safe landing but search and rescue had to be called. If the highly
>respected geniuses can create a thing like B Baum describes, surely
>some one can figure that it would save lives and money in search and
>rescue. Better than an ELT. Think about the search for Faucett last
>year.
>Let's pray that progress continues and is not stopped by some dumb ass
>legislator that likes to make rules. F Robinson.

The discussion included the concept that cellphones often do not work
on those mountains, or in gliders. Various folks had noticed this.
I notice this on a 2600 foot mountain, with far fewer than 16 million
population in sight.

Cell phones often don't work back in the mountains, or the valleys
between them. Look up the details of the family who got stuck in the
snow in southwestern Oregon a few years ago -- the cellphone did not
work, and one member of the family died trying to walk out. ( I think
that he should have (a) stayed with the family in the car, and (b) had
a way to recharge the cellphone. )

Banning cellphone use in aircraft is not some dumb legislator -- it
is the result of engineers knowledgable in the effects and principles
of cellphone systems. Banning them in cars while driving is dumb
legislators who don't understand real studies of safety...

If you want progress, use a satellite phone system that will work
anywhere you get a view of the sky. I think Spot is one such system.
Do not rely on cellular systems that have incomplete coverage.

Alan