More wireless in airplanes stuff

Don Hammer wrote:

I agree with your dad, but if you look at how much circuitry it takes
for a wireless connection to replace a simple length of wire, I don't
think you can say that wireless is less complex.

Matt


Matt,
Trust me, by the time you run a bunch of wires to each seat along with
net hubs etc in a larger aircraft, one wireless router saves a bunch
of weight and cost.

Weight and cost, yes, complexity, no.


Matt

Yes, complexity is higher, but the complexity is at the chip level.
This stuff is getting cheap and it's down to the hobbist level now.
check out http://www.sparkfun.com

As an Aerospace engr I always marveled at the no cell phone use or
other banned electronic devices on aircraft. The amount of testing we
go through to cert a piece of avionics is mind boggling and quite $$$$.
Some of these levels (EMI) would fry you.

"Bob" wrote

The amount of testing we
go through to cert a piece of avionics is mind boggling and quite $$$$.
Some of these levels (EMI) would fry you.

I'm not sure what you are saying. Is it that the EMI necessary to interfere
with the avionics would fry you?
--
Jim in NC

We subject the units under test to very high levels of EMI. This is
done in a shielded room. You would not survive these levels. I won't
even look through the window of the test chamber.

So, with regard to the ban of certain electronic devices such as cell
phones, the cell phone is many orders of magnitude less powerful then
what we cert to.

"Bob" wrote in message
oups.com...
We subject the units under test to very high levels of EMI. This is
done in a shielded room. You would not survive these levels. I won't
even look through the window of the test chamber.

So, with regard to the ban of certain electronic devices such as cell
phones, the cell phone is many orders of magnitude less powerful then
what we cert to.

That is what I thought you were saying.

I must admit, I have always thought the same to be true, and have ridden
commercial flights, while holding a small PDA GPS to the window, so it could
see the satellites, at least on one side of the sky. It was interesting,
and entertaining, knowing what the speed altitude, and rate of climb was.
One time we diverted around a storm cell, while on approach, and the track
drew a nice 1/2 circle around it, and went back on course.

Thanks for confirming it for me. ;-)
--
Jim in NC

Weight and cost, yes, complexity, no.


Matt

Maybe I don't understand what you are getting at. I put wireless in a
Gulfstream G-550. System was a short wire from the onboard server
(Part of the hight-speed data system) to the wireless hub and and
power to the hub. My other option was wires and jacks to each seat
and the cockpit from a hub. Why is wireless more complex?

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Don Hammer wrote:
Weight and cost, yes, complexity, no.


Matt


Maybe I don't understand what you are getting at. I put wireless in a
Gulfstream G-550. System was a short wire from the onboard server
(Part of the hight-speed data system) to the wireless hub and and
power to the hub. My other option was wires and jacks to each seat
and the cockpit from a hub. Why is wireless more complex?

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I think what he's getting at is the hidden complexity... the software,
chip design, etc.

For your wireless network to work reliably, all of that has to work
properly. And it is effectively untestable by the installer and
uncertified (implying (perhaps falsely) that it is incompletely tested).

Frank

Frank van der Hulst wrote:

Don Hammer wrote:

Weight and cost, yes, complexity, no.


Matt



Maybe I don't understand what you are getting at. I put wireless in a
Gulfstream G-550. System was a short wire from the onboard server
(Part of the hight-speed data system) to the wireless hub and and
power to the hub. My other option was wires and jacks to each seat
and the cockpit from a hub. Why is wireless more complex?

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I think what he's getting at is the hidden complexity... the software,
chip design, etc.

For your wireless network to work reliably, all of that has to work
properly. And it is effectively untestable by the installer and
uncertified (implying (perhaps falsely) that it is incompletely tested).

Exactly. Wire is pretty darn simple. A wireless router is a rather
complex assembly of hardware and software. A few runs of wire have been
known to function for more than 50 years. I wouldn't bet much on a
typical router being function 50 years down the road.


Matt

"Matt Whiting" wrote

Exactly. Wire is pretty darn simple. A wireless router is a rather
complex assembly of hardware and software. A few runs of wire have been
known to function for more than 50 years. I wouldn't bet much on a
typical router being function 50 years down the road.

While what you say is true, I don't agree with the premise. Wireless
routers are no more complex than hard wired routers.

You will be carrying around the wire for 50 years, with the weight penalty
for that whole time. Servicing the plane will be more complex, working
around the extra wire. Less functionality, due to passengers having
constraints of being tied down by a wire, in whatever arrangement you put
them in, is a fact of life. It also means something more to trip over, not
being able to move from seat to seat easily with your computer or other
wireless device, and wires tip over drinks and things. If you want to have
wireless devices other than computers, like headphones for music or movies
added, you don't have to add another whole set of wires. The flexibility is
worth the extra complexity, no matter what the possible small difference in
reliability could be, if there even is a difference.

Given, wireless routers fail. So do hard wired routers. So do airborne
high speed data links. If data is that important, you carry a backup data
link. Carry an extra wireless router too, and still be ahead on the weight.
You would have to have a backup hard wired router, anyway.

Things are changing in digital communications so fast, I would say your
chance of using the same wire in 50 years is about nil. There will be
different standards and needs by then. At upgrade time, you will have to
tear out the wire, and do it all again. More unnecessary expensive
installation. Drop a new wireless router in, and be up to speed, with zero
down time. Another bonus.

I don't have a dog in this fight, since I don't have a Falcon, or Jetstream,
or even a Bo. I just wanted to air my views.

Good'day. :-)
--
Jim in NC

Another app... for homebuilt/GA aircraft.

http://www.frogpad.com/information/bluefroginfo.asp

Imagine a Bluetooth keypad strapped to your knee... it can be configured
to change radio channels, set your transponder, etc.

Frank