AM radio reception inside passenger planes?

[Henry Kolesnik]

Amen!
"Some Guy" <Some@Guy.com> wrote in message news:41BC9EBE.752909A7@Guy.com...

Dave Bushong wrote:

[Dramatic generalization mode on]
Nearly all aircraft accidents are caused by a series of unlikely
events all happening together, none of which by itself would be
a problem.
[Dramatic generalization mode off]

Nice sweeping piece of dis-information there buddy.

How about this: Nearly all aircraft accidents are caused by a single
failure in a single component or a single failure to do something.
Pitot tubes that are taped over. Fuel tanks that explode. Structural
failure that causes entire pieces of fuselage to peel off while in
flight. Fuel leaks that turn large jets into gliders. Cabin fires
caused by the overload of a single wire powering the entertainment
system. Air pressure equalization valves that bleed cabin air
rendering the occupants unconscious and results in a ghost plane
flying thousands of miles before crashing. Failure to de-ice.
Overloading resulting in stalling upon take-off. Failure to secure
cargo upon takeoff. Being struck in the fuel tank by a piece of
debris on the runway kicked up by the tires. An engine ingesting a
flock of birds. A shipment of improperly-disarmed oxygen generators
placed in the cargo hold. Lack of proper lubrication of tail
jack-screws. Tail fins that are not as strongly connected to the
fuselage as they should be. Need I continue?

A series of events will surely happen AFTER any of those incidents,
none of which are either unlikely or unexpected, and by and large
would have no effect on the outcome.

Will the in-flight use of an FM radio EVER cause a plane to run out of
fuel? Or cause a sudden ice build-up on the wings? Or blow out a
tire upon landing? Or an overload of the electrical system leading to
a fire? Will the feeble RF emitted by the LO even be detectable
OUTSIDE the plane, where the plane's antennas are located?

If you read the various documents on the web relating to issues of
in-flight use of PED's (personal electronic devices) it's clear that

1) The FAA and NTSB are either negligent or a bunch of cowards for not
forcing the AIRCRAFT MANUFACTURERS to determine the level of
susceptibility of their planes to PED's. Instead the issue is pawned
off to the aircraft operators when logically it should be the airplane
makers!

2) The use of cell phones (analog and perhaps more frequently GSM)
seems to have the most influence of any PED. The next most frequent
culprit seems to be laptop computers.

3) No incidence of communication failure or disruption seems to have
ever been documented by a passenger's FM radio receiver.

4) MANY MANY incidences of navigation equipment errors caused by
improper installation / connection of the equipment, or interference
caused by one of the plane's other systems where these were first
attributed to a PED.

5) Planes have to fly near high-power commercial radio and TV
transmission towers. They fly through the beams of powerful radar
signals. They get struck by lightning. There are those that say that
for a (commercial jet) to be certified there is no way that a
certified plane could be susceptible to the stray RF given off by
PED's (at least PED's that are non-intentional radiators).

6) The authorities would probably not admit it, but the ban or
restrictions on PED use in planes probably has more to do with
insurance/liability reasons, or passenger distraction reasons, than it
does for technical (interference) reasons.

PED's are here to stay. There will be more of them, and people will
use them wherever they are. It makes just as much sense to ban them
or perform half-ass on-board supervision on a plane for these devices
as it is to ban them from cars. PED's used cars cause injury and
death each year (due to driver in-attention). Instead of banning
radios, phones, and entertainment systems in cars, they instead come
from the factory with them installed! Where's your crusade against
that situation? Where are your dire warnings here?

Would you want to add one more "unlikely event" to your next
flight?

Nothing caused by or brought on board by a passenger (short of
alcohol, a gun, a bomb, or otherwise a strong intent to do harm) will
or has ever caused anything bad to happen on a plane or to a plane.
No gun ever brought on board (and there have been MANY!) has ever
discharged. No can of hairspray has ever exploded in the cargo hold.

There is relatively little variety in the types, makes or models of
commercial airplanes flying today. There is a high degree of
uniformity in construction of these vehicles. There have been
millions of flights over the past, say 20 years. There have been many
hundred million passengers carried by these planes. There surely has
been ample opportunity for all sorts of PED's to be used on these
planes (surreptitiously or with consent). If any particular plane
model (or even specific plane) had a systemic or inherent
susceptibility to a PED, it would have been recognized by now.

 

[Charles Newman]

"Some Guy" <Some@Guy.com> wrote in message news:41BC9EBE.752909A7@Guy.com...

Dave Bushong wrote:

[Dramatic generalization mode on]
Nearly all aircraft accidents are caused by a series of unlikely
events all happening together, none of which by itself would be
a problem.
[Dramatic generalization mode off]

Nice sweeping piece of dis-information there buddy.

How about this: Nearly all aircraft accidents are caused by a single
failure in a single component or a single failure to do something.
Pitot tubes that are taped over. Fuel tanks that explode. Structural

What is a Pitot tube anyway? I have seen a switch for most aircraft
in Flight Simulator marked "Pitot Heat", what is that?

 

[Dave Bushong]

Lots of data, not much information. No cites given.

Angry crap.

Some Guy wrote:

Dave Bushong wrote:

[Dramatic generalization mode on]

Nearly all aircraft accidents are caused by a series of unlikely
events all happening together, none of which by itself would be
a problem.

[Dramatic generalization mode off]

Nice sweeping piece of dis-information there buddy.

How about this: Nearly all aircraft accidents are caused by a single
failure in a single component or a single failure to do something.
Pitot tubes that are taped over. Fuel tanks that explode. Structural
failure that causes entire pieces of fuselage to peel off while in
flight. Fuel leaks that turn large jets into gliders. Cabin fires
caused by the overload of a single wire powering the entertainment
system. Air pressure equalization valves that bleed cabin air
rendering the occupants unconscious and results in a ghost plane
flying thousands of miles before crashing. Failure to de-ice.
Overloading resulting in stalling upon take-off. Failure to secure
cargo upon takeoff. Being struck in the fuel tank by a piece of
debris on the runway kicked up by the tires. An engine ingesting a
flock of birds. A shipment of improperly-disarmed oxygen generators
placed in the cargo hold. Lack of proper lubrication of tail
jack-screws. Tail fins that are not as strongly connected to the
fuselage as they should be. Need I continue?

A series of events will surely happen AFTER any of those incidents,
none of which are either unlikely or unexpected, and by and large
would have no effect on the outcome.

Will the in-flight use of an FM radio EVER cause a plane to run out of
fuel? Or cause a sudden ice build-up on the wings? Or blow out a
tire upon landing? Or an overload of the electrical system leading to
a fire? Will the feeble RF emitted by the LO even be detectable
OUTSIDE the plane, where the plane's antennas are located?

If you read the various documents on the web relating to issues of
in-flight use of PED's (personal electronic devices) it's clear that

1) The FAA and NTSB are either negligent or a bunch of cowards for not
forcing the AIRCRAFT MANUFACTURERS to determine the level of
susceptibility of their planes to PED's. Instead the issue is pawned
off to the aircraft operators when logically it should be the airplane
makers!

2) The use of cell phones (analog and perhaps more frequently GSM)
seems to have the most influence of any PED. The next most frequent
culprit seems to be laptop computers.

3) No incidence of communication failure or disruption seems to have
ever been documented by a passenger's FM radio receiver.

4) MANY MANY incidences of navigation equipment errors caused by
improper installation / connection of the equipment, or interference
caused by one of the plane's other systems where these were first
attributed to a PED.

5) Planes have to fly near high-power commercial radio and TV
transmission towers. They fly through the beams of powerful radar
signals. They get struck by lightning. There are those that say that
for a (commercial jet) to be certified there is no way that a
certified plane could be susceptible to the stray RF given off by
PED's (at least PED's that are non-intentional radiators).

6) The authorities would probably not admit it, but the ban or
restrictions on PED use in planes probably has more to do with
insurance/liability reasons, or passenger distraction reasons, than it
does for technical (interference) reasons.

PED's are here to stay. There will be more of them, and people will
use them wherever they are. It makes just as much sense to ban them
or perform half-ass on-board supervision on a plane for these devices
as it is to ban them from cars. PED's used cars cause injury and
death each year (due to driver in-attention). Instead of banning
radios, phones, and entertainment systems in cars, they instead come
from the factory with them installed! Where's your crusade against
that situation? Where are your dire warnings here?


Would you want to add one more "unlikely event" to your next
flight?


Nothing caused by or brought on board by a passenger (short of
alcohol, a gun, a bomb, or otherwise a strong intent to do harm) will
or has ever caused anything bad to happen on a plane or to a plane.
No gun ever brought on board (and there have been MANY!) has ever
discharged. No can of hairspray has ever exploded in the cargo hold.

There is relatively little variety in the types, makes or models of
commercial airplanes flying today. There is a high degree of
uniformity in construction of these vehicles. There have been
millions of flights over the past, say 20 years. There have been many
hundred million passengers carried by these planes. There surely has
been ample opportunity for all sorts of PED's to be used on these
planes (surreptitiously or with consent). If any particular plane
model (or even specific plane) had a systemic or inherent
susceptibility to a PED, it would have been recognized by now.

 

[TaxSrv]

"Dave Bushong" wrote:

Nearly all aircraft accidents are caused by a series of unlikely
events
all happening together, none of which by itself would be a problem.

I'll bet there's no record of a U.S. airline accident caused by faulty
navigation equipment for any reason, or at least excluding maybe the
early years. General aviation, yes.

Would you want to add one more "unlikely event" to your next
flight?

I have no problem with any airline with a flat "no" policy on this,
because things do happen even if rarely. NASA gathers the PED
incident data, and over a 14-year period, there have been less than
100 events, mostly in cruise, most not classed as potentially serious.
The reason they were reported is because the equipment told the pilot
about it, and often ATC did so too. Also, NASA has to take the
pilot's word for it that the anomaly was caused by a PED.

Fred F.

 

[chuck]

Dave, try these:

Boeing has investigated alleged interference from portable electronic
devices (PEDs) and concluded:

"As a result of these and other investigations, Boeing has not been able
to find a definite correlation between PEDs and the associated reported
airplane anomalies."

You can look this up at:

http://www.boeing.com/commercial/aeromagazine/aero_10/interfere_textonly.html
Aero 10 - Interference from Electronic Devices

Here's another one:

http://www.rvs.uni-bielefeld.de/publications/Incidents/DOCS/Research/Rvs/Article/EMI.html
Electromagnetic interference with aircraft systems


Dave Bushong wrote:

Lots of data, not much information. No cites given.

Angry crap.

Some Guy wrote:

Dave Bushong wrote:

[Dramatic generalization mode on]

Nearly all aircraft accidents are caused by a series of unlikely
events all happening together, none of which by itself would be
a problem.


[Dramatic generalization mode off]

Nice sweeping piece of dis-information there buddy.

How about this: Nearly all aircraft accidents are caused by a single
failure in a single component or a single failure to do something.
Pitot tubes that are taped over. Fuel tanks that explode. Structural
failure that causes entire pieces of fuselage to peel off while in
flight. Fuel leaks that turn large jets into gliders. Cabin fires
caused by the overload of a single wire powering the entertainment
system. Air pressure equalization valves that bleed cabin air
rendering the occupants unconscious and results in a ghost plane
flying thousands of miles before crashing. Failure to de-ice.
Overloading resulting in stalling upon take-off. Failure to secure
cargo upon takeoff. Being struck in the fuel tank by a piece of
debris on the runway kicked up by the tires. An engine ingesting a
flock of birds. A shipment of improperly-disarmed oxygen generators
placed in the cargo hold. Lack of proper lubrication of tail
jack-screws. Tail fins that are not as strongly connected to the
fuselage as they should be. Need I continue?

A series of events will surely happen AFTER any of those incidents,
none of which are either unlikely or unexpected, and by and large
would have no effect on the outcome.

Will the in-flight use of an FM radio EVER cause a plane to run out of
fuel? Or cause a sudden ice build-up on the wings? Or blow out a
tire upon landing? Or an overload of the electrical system leading to
a fire? Will the feeble RF emitted by the LO even be detectable
OUTSIDE the plane, where the plane's antennas are located?

If you read the various documents on the web relating to issues of
in-flight use of PED's (personal electronic devices) it's clear that

1) The FAA and NTSB are either negligent or a bunch of cowards for not
forcing the AIRCRAFT MANUFACTURERS to determine the level of
susceptibility of their planes to PED's. Instead the issue is pawned
off to the aircraft operators when logically it should be the airplane
makers!

2) The use of cell phones (analog and perhaps more frequently GSM)
seems to have the most influence of any PED. The next most frequent
culprit seems to be laptop computers.

3) No incidence of communication failure or disruption seems to have
ever been documented by a passenger's FM radio receiver.

4) MANY MANY incidences of navigation equipment errors caused by
improper installation / connection of the equipment, or interference
caused by one of the plane's other systems where these were first
attributed to a PED.

5) Planes have to fly near high-power commercial radio and TV
transmission towers. They fly through the beams of powerful radar
signals. They get struck by lightning. There are those that say that
for a (commercial jet) to be certified there is no way that a
certified plane could be susceptible to the stray RF given off by
PED's (at least PED's that are non-intentional radiators).

6) The authorities would probably not admit it, but the ban or
restrictions on PED use in planes probably has more to do with
insurance/liability reasons, or passenger distraction reasons, than it
does for technical (interference) reasons.

PED's are here to stay. There will be more of them, and people will
use them wherever they are. It makes just as much sense to ban them
or perform half-ass on-board supervision on a plane for these devices
as it is to ban them from cars. PED's used cars cause injury and
death each year (due to driver in-attention). Instead of banning
radios, phones, and entertainment systems in cars, they instead come
from the factory with them installed! Where's your crusade against
that situation? Where are your dire warnings here?


Would you want to add one more "unlikely event" to your next
flight?



Nothing caused by or brought on board by a passenger (short of
alcohol, a gun, a bomb, or otherwise a strong intent to do harm) will
or has ever caused anything bad to happen on a plane or to a plane. No
gun ever brought on board (and there have been MANY!) has ever
discharged. No can of hairspray has ever exploded in the cargo hold.

There is relatively little variety in the types, makes or models of
commercial airplanes flying today. There is a high degree of
uniformity in construction of these vehicles. There have been
millions of flights over the past, say 20 years. There have been many
hundred million passengers carried by these planes. There surely has
been ample opportunity for all sorts of PED's to be used on these
planes (surreptitiously or with consent). If any particular plane
model (or even specific plane) had a systemic or inherent
susceptibility to a PED, it would have been recognized by now.

 

[phoneguy99]

TaxSrv wrote:

cabin. But has anybody ever heard a cabin announcement during flight
to turn off any devices?

Fred F.

YES.

I was on a flight from Toronto to Tampa a few years ago and somewhere
over the Carolinas the pilot came on the PA and calmly informed us they
have spent the last 45 mins trying to find the source of a buzzing noise
on their radios. (He also reinforced the fact that they were all still
working, but there was a buzzing noise on the audio.) He politely told
everyone to turn off any electronic devices they may be using. The
flight attendants quickly verified passenger compliance a few minutes
later. About 10 mins after that, he came on the PA to say it was gone
and instructed everyone to leave them off for the duration of the
flight, not that there was any danger, but it was distracting to have a
constant buzzing coming over the radio.

I did notice a couple of laptops had been fired up, but sitting in your
seat is not exactly an ideal vantage point to see what everyone else was
doing.

Do I think someone's radio is going to make the plane fall from the sky?
Of course not. Is there a remote possibility it could cause birdies or
other RF anomalies that 'could' affect things? Sure.

On one flight, a few years earlier still, WITH the ok from the flight
deck (you know, in those friendlier years when you could say 'hi'
through the open cockpit door when you were coming out of the bathroom)
I used my FT-470 handie for a few mins. The pilot knew what ham radio
was, knew I was going to be on UHF (because I told him that's where I
would try for a quick QSO) and he very politely said "Sure, but only for
5 minutes, then turn it off. What seat are you in?" I thanked him
kindly, returned to my window seat, and did manage to get into some
repeater in Maine for about a minute or two. The funny thing was he was
in the galley as we were getting off the plane, I thanked him again, and
he asked if I had any luck, I said 'yep' and asked him if I came over
anything up front. He smiled and said "Nope, and we were up there
looking to see if you would."

The purpose of my sharing this snippet from many years ago is not to
illustrate there's no danger in using a receiver (or in this case, a low
power transmitter) while on a plane, but using one does not
automatically imply you're going to write off the comm/nav systems.

My $.02

 

[Ed Price]

"TaxSrv" <n3_eu@comcast.net> wrote in message
news:2YidnWP6YuJIHiHcRVn-sw@comcast.com...

Hey folks, let's not overdo the safety aspects here, so no one panics
if aboard an airliner and sees someone using a radio. I doubt any
device emitting small RF will be able to make comm reception
unreadable. Even if it did, there are then fallback procedures which
the pilot is required to know by heart,

Your doubts do not stand up to empirical evidence. Stick to assertions that
have a basis in fact and not just in your mind.

The whole point is to not weaken the chain of redundant flight safety
features just to allow a piece of meat cargo to be electronically
entertained.

Now the same considerations apply to flying the approach and landing,
but the pilot would rather not have to deal with potential
interference to either nav or comm, especially if the airport is 1/2
mile visibility in fog. Thus, it's not too uncommon for the pilot to
grant permission to use a radio device only while in cruise.

And all passengers will immediately comply, because they are all concerned
about not creating a dangerous electronic environment. Games will be halted,
spreadsheets closed, and porn movies terminated. Cabin attendants will
notice immediate 100% compliance, and will not be distracted from other
duties to repeatedly remind, cajole or threaten recalcitrant passengers.

Fred, your world is much different than any I have ever seen.

Ed
wb6wsn

 

[Ed Price]

"Some Guy" <Some@Guy.com> wrote in message news:41BC9EBE.752909A7@Guy.com...

Dave Bushong wrote:

[Dramatic generalization mode on]
Nearly all aircraft accidents are caused by a series of unlikely
events all happening together, none of which by itself would be
a problem.
[Dramatic generalization mode off]

Nice sweeping piece of dis-information there buddy.


Will the in-flight use of an FM radio EVER cause a plane to run out of
fuel? Or cause a sudden ice build-up on the wings? Or blow out a
tire upon landing? Or an overload of the electrical system leading to
a fire? Will the feeble RF emitted by the LO even be detectable
OUTSIDE the plane, where the plane's antennas are located?

It's so damn complicated that nobody can answer the question. Airliners are
going in the direction of all-electronic flight control and management
systems. Somebody's LO won't affect fuel consumption, uhh, unless it affects
the microprocessor or sensors controlling the engine. It's unlikely, a lot
of work goes toward making it extremely unlikely. But remember, I said
unlikely, not impossible.

Ice on the wings? What controls the de-icing boot?

Blow a tire? Is the braking circuit all-mechanical, or do you have something
akin to power boost and anti-lock sensing?

Is the LO detectable outside the fuselage, near the antennas? YES, damn it,
YES. I have measured it, with calibrated field strength meters. Don't give
me your damn dumb opinions when I have seen the results myself. And is the
LO emission strong enough to degrade or deny a navcom signal. YES or MAYBE
or COULD BE. It depends on the passenger's radio, how he holds it, is he
next to a window, is the fuselage unusually leaky to RF, what seat is the
passenger in, what station is the radio tuned to, are the batteries new or
weak, how weak is the navcom signal, what is the attitude of the aircraft,
is the navcom receiver getting old, even are there multiple passenger
receivers acting on the navcom (if they are all like you, how many of 300
passengers will have personal electronics running?).

The POSSIBILITY of interference is undeniable. The PROBABILITY is very
difficult to predict. The safe course is to deny you your entertainment for
several hours to ensure maximum safety. Is that too much to ask of you?

Ed
wb6wsn

 

[Ed Price]

"chuck" <chuck@nospam.net> wrote in message
news:XK3vd.1528$2J2.362@newsread2.news.atl.earthlink.net...

Dave, try these:

Boeing has investigated alleged interference from portable electronic
devices (PEDs) and concluded:

"As a result of these and other investigations, Boeing has not been able
to find a definite correlation between PEDs and the associated reported
airplane anomalies."

You can look this up at:

http://www.boeing.com/commercial/aeromagazine/aero_10/interfere_textonly.html
Aero 10 - Interference from Electronic Devices

Here's another one:

http://www.rvs.uni-bielefeld.de/publications/Incidents/DOCS/Research/Rvs/Article/EMI.html
Electromagnetic interference with aircraft systems

Not to cast aspersions on Boeing research, as they are quite reputable, but
if they had found correlatable evidence of PED's interfering with avionics,
who gets sued? The passenger, a Hong Kong radio manufacturer, or the
aircraft builder?

In any case, the reports of interference keep coming in, despite the
difficulty of replicating the problem. Obviously, the problem is rare and
elusive, but, as in most Electromagnetic Compatibility issues, the easiest,
surest, and cheapest cure is to control the source of the problem.

Just turn off ALL passenger electronics for the duration of the flight. Read
a book for 2 hours, and let your kid kick the seat in front of him.

Ed
wb6wsn


Ed
wb6wsn

 

[Ed Price]

"phoneguy99" <phoneguy99unspam@unspamsympatico.ca> wrote in message
news:fh5vd.2407$%p1.245540@news20.bellglobal.com...

TaxSrv wrote:
cabin. But has anybody ever heard a cabin announcement during flight
to turn off any devices?

Fred F.

YES.

SNIP

On one flight, a few years earlier still, WITH the ok from the flight deck
(you know, in those friendlier years when you could say 'hi' through the
open cockpit door when you were coming out of the bathroom) I used my
FT-470 handie for a few mins. The pilot knew what ham radio was, knew I
was going to be on UHF (because I told him that's where I would try for a
quick QSO) and he very politely said "Sure, but only for 5 minutes, then
turn it off. What seat are you in?" I thanked him kindly, returned to my
window seat, and did manage to get into some repeater in Maine for about a
minute or two. The funny thing was he was in the galley as we were getting
off the plane, I thanked him again, and he asked if I had any luck, I said
'yep' and asked him if I came over anything up front. He smiled and said
"Nope, and we were up there looking to see if you would."

The purpose of my sharing this snippet from many years ago is not to
illustrate there's no danger in using a receiver (or in this case, a low
power transmitter) while on a plane, but using one does not automatically
imply you're going to write off the comm/nav systems.

My $.02

It also illustrates the safety concern. Although there were no observed
improper responses from the aircraft avionics, "we were up there looking to
see if you would" (cause a problem) is very disturbing. You added to the
pilots' workload for several minutes, involving them in an interesting
science project. The cockpit is normally a very busy place, so what tasks
were slighted to allow time for your project?

How would you have felt if the flight crew was diverting some of their time
to help somebody with a tough crossword puzzle? Was a Maine QSO worth it
all? I'd have given you a whole quarter to pull the battery from your HT!

Ed
wb6wsn

 

[Bob Myers]

"Some Guy" <Some@guy.com> wrote in message news:41BB8C6A.FD42C1E7@guy.com...

You guys are acting as if the engines and flight control surfaces of
an aircraft are intimately tied to the plane's radio receiver, and the
slightest odd or out-of-place signal that it receives is enough to
send any plane into a tail spin.

Not at all; however, there IS obviously a connection between
various flight control functions (such as, say, the autopilot) and
the information given by the avionics (esp. "nav" radios using
ground-based sources such as VORs, etc.). It's not going to
"send any plane into a tail spin", but it can certainly cause some
problems.

All this while the air travel industry is considering allowing
passengers to use their own cell phones WHILE THE PLANES ARE IN FLIGHT
by adding cell-phone relay stations to the planes and allowing any
such calls to be completed via satellite. So I guess the feeble
radiation by my FM radio (powered by 2 AAA batteries) is enough to
cause a plane to dive into the ocean, but the guy next to me putting
out 3 watts of near-microwave energy is totally safe.

You DO realize that these are on very different frequencies, and
that the emissions of an FM superheterodyne radio are very
likely to fall right in the aviation band, don't you? Hint: if you have
to go look up "superheterodyne" to understand this question, I
have serious doubts regarding your qualifications to comment on it.

Getting back to the original question (poor to non-existant AM
reception), I understand the idea of aperature and long wavelenths of
AM radio and the size of airplane windows - but what about the effect
of ALL the windows on a plane? Don't they create a much larger
effective apperature when you consider all of them?

No. It's not the TOTAL area of the "apperatures" [sic] that
is important, it's the size of the individual openings. If this were
not so, then a conductive mesh could never be effective as a
shield.

And since the
plane isin't grounded, isin't the exterior shell of a plane
essentially transparent to all RF (ie it's just a re-radiator) because
it's not at ground potential?

No. "Ground potential" has absolutely nothing to do
with it. Hint: what do you think is the RF environment
within a perfectly conducting sealed enclosure, with
respect to outside sources, even if that enclosure is
completely isolated from any other surface or conductor?

Bob M. (KC0EW)

 

[Bob Myers]

"Charles Newman" <charlesnewman1@comcast.net.spammers.will.be.shot.on.sight>
wrote in message news:yqidnc_QoZSSMiHcRVn-2Q@comcast.com...

What is a Pitot tube anyway? I have seen a switch for most aircraft
in Flight Simulator marked "Pitot Heat", what is that?

A pitot tube is a tube which protrudes from the aircraft
body into the path of the air through which the aircraft is
flying. They are used for such things as determining airspeed
(which is the speed of the aircraft through the air, not over
the ground), and in some meteorological conditions are
prone to becoming clogged with ice. Hence, "pitot heat"
is just that - the switch in question controls a heater (most
often, electric) built into the pitot tube, which keeps in clear
of ice. Losing pitot pressure due to having the damn thing
plugged up is generally considered a Bad Thing, and
unfortunate events have been known to follow such an
occurence.

Bob M.

 

[Dave Holford]

My world is as an instrument rated pilot and one who services aircraft
avionics. And you must have missed my other post where I said PEDs
should be off at all times.

Fred F.

The I presume you specified AM because the LO operates outside aviation
frequencies (now that LORAN A is gone), unlike the LO in an FM broadcast
receiver which covers the VHF localizer and VOR frequencies very nicely.

Dave

 

[Dave Holford]

All this while the air travel industry is considering allowing
passengers to use their own cell phones WHILE THE PLANES ARE IN FLIGHT
by adding cell-phone relay stations to the planes and allowing any
such calls to be completed via satellite. So I guess the feeble
radiation by my FM radio (powered by 2 AAA batteries) is enough to
cause a plane to dive into the ocean, but the guy next to me putting
out 3 watts of near-microwave energy is totally safe.

I can't provide technical details of the operation because I don't know
them; but I am familiar with a number of totally RF screened environments
where use of electronic devices are tightly controlled. However, internal
relays are used to permit operation of cell phones - which I always
understood were specific models which had been certified for such use.

Dave

 

[Some Guy]

Dave Holford wrote:

All this while the air travel industry is considering allowing
passengers to use their own cell phones WHILE THE PLANES ARE
IN FLIGHT by adding cell-phone relay stations to the planes

I am familiar with a number of totally RF screened environments
where use of electronic devices are tightly controlled.
However, internal relays are used to permit operation of cell
phones

The point was not how the planes are being equipped to handle
in-flight cell-phone use.

The point was that consideration is being made to allow cell phones to
be used while the planes are in flight. That intentional radiating
PED's are even being considered for in-flight use when so much hype
and concern is being given to the weak radiation potential of some
non-intentional radiators like am/fm radios.

BTW, what is the potential of the local oscillators of small hand-held
LCD-screen TV's to overlap with aviation frequencies?

 

[Dave VanHorn]

On the way back, I spoke with a commercial pilot who was deadheading, on
this issue.
He said that it's not all that unusual to hear radio interference once they
have allowed the devices on, but when they are in cruise, they aren't
normally doing any urgent communications, so it isn't much of an issue. If
something comes up, then they will pass the word to shut down the PEDs.

On takeoff and landing though, the comms are much more rapid, and the
consequences of missing one transmission are much higher. They need to hear
all the comms, not just between themselves and the tower, but what the other
pilots are saying as well. Add to this, the fact that aircraft comms are
AM, which is inherently muddy, and it's easy to see why they take the extra
precautions.

 

[Bob Myers]

"Some Guy" <Some@guy.com> wrote in message news:41C0EA5C.65B51751@guy.com...

The point was that consideration is being made to allow cell phones to
be used while the planes are in flight. That intentional radiating
PED's are even being considered for in-flight use when so much hype
and concern is being given to the weak radiation potential of some
non-intentional radiators like am/fm radios.

Because, as has already been pointed out, of the
differences in emission characteristics (and specifically
the frequency ranges likely to be affected) of the two
classes of devices.

BTW, what is the potential of the local oscillators of small hand-held
LCD-screen TV's to overlap with aviation frequencies?

I believe they should be somewhat less than is the case
with an FM receiver, but they're still a bad idea for
the same reason. Note that the analysis of the likely
frequencies provided so far has dealt solely with the
first-order effects of the receiver's local oscillator; we
have NOT discussed harmonics or other unwanted
emissions.

The problem is most obvious with FM receivers because
the standard 1st LO frequency is 10.7 MHz, and the
top of the FM broadcast band is adjacent to the bottom
of the aviation band (108 MHz) - which means that
simply adding the LO frequency to standard FM
broadcast frequencies can take you instantly into overlap
with the bottom 10.7 MHz of the aviation band (and
unfortunately, that's where a lot of the radionavigation
systems within that band tend to be). But this does
not mean that receivers for other services would not
cause similar problems. VHF television covers
frequencies below and above both FM and
aviation (two bands, 54-88 MHz for channels 2
through 6, and 174 to 216 MHz for channels 7
through 13). It is certainly very possible that receivers
intended for these bands would emit in the aviation
band. Other adjacent services that may be of concern
include public-service and commerical communication
bands (i.e., police scanners) and the 2-meter amateur
band.

Bob M.

 

[TaxSrv]

"Dave VanHorn" wrote:

They need to hear
all the comms, not just between themselves and the tower, but what
the other pilots are saying as well. Add to this, the fact that
aircraft
comms are AM, which is inherently muddy, and it's easy to see why
they take the extra precautions.

The design of newer comms doesn't help either. If they have automatic
squelch, set to break at say 1uV RF in, then obviously it doesn't take
much interference to break squelch. Then, they also may have "audio
leveling" -- a great feature when commonly using headphones -- but the
effect there will be to take a few uV of noise and amplify the audio
component to the level you hear when ATC hits you with as much as 50W,
and it's heard constantly between transmissions, to be hopefully
silenced when ATC talks. But not necessarily the case in monitoring
comms of other aircraft, where especially general aviation,
less-than-properly-functional 7W units can be relatively weak.

Fred F.

 

[Watson A.Name - \"Watt Su]

"Richard Clark" <kb7qhc@comcast.net> wrote in message
news:mf2nr0hn2u850gube0gsuo07df1hs5ee1b@4ax.com...

On Sat, 11 Dec 2004 14:11:44 -0800, "Ed Price" <edprice@cox.net
wrote:

You
are asking him to allow a potentially dangerous device to be operated
just
for your convenience and entertainment. Switch roles for just a
minute.

Hi Ed,

This would make sense (to switch roles) if the administration hadn't
trumped that call. Reports recently indicate that the FAA may soon
allow anyone, anytime, to make cell phone calls while in flight.

Anything goes for a price. The FDA has proven that it is no longer
the watchdog of medicine, and the FCC is the gateway for spectrum
bargains and marketplace sweeps.

With these acronyms, one may well wonder what the "F" stands for.

73's
Richard Clark, KB7QHC

If you make your own TRF receiver, with no LO, it won't interfere with
anything. In fact, you can then put an AM detector in it, and also
listen to the aircraft chatter.

Another way is to listen to stations at or below 97.3 MHz, which would
keep the LO at 108 MHz or below.

 

[Watson A.Name - \"Watt Su]

"Some Guy" <Some@guy.com> wrote in message
news:41BB8C6A.FD42C1E7@guy.com...

What a load of horse shit.

You guys are acting as if the engines and flight control surfaces of
an aircraft are intimately tied to the plane's radio receiver, and the
slightest odd or out-of-place signal that it receives is enough to
send any plane into a tail spin.

No, the laws say that you can be arrested for breaking them, and one way
to break them is to use a FM radio while the aircraft is flying.

All this while the air travel industry is considering allowing
passengers to use their own cell phones WHILE THE PLANES ARE IN FLIGHT
by adding cell-phone relay stations to the planes and allowing any
such calls to be completed via satellite. So I guess the feeble
radiation by my FM radio (powered by 2 AAA batteries) is enough to
cause a plane to dive into the ocean, but the guy next to me putting
out 3 watts of near-microwave energy is totally safe.

You don't know what you're talking about. With the attitudes of the air
marshals nowadays, making airliners turn around and go back to their
departure point just because a passenger is unruly, there is a high
probability that one of them is flying along on your flight, and if he
sees an earphone hanging out of your ear, you might be that unruly
passenger they arrest at the departure point. Especially with your
nasty attitude!

What about my hand-held GPS unit? Any chance me using it (during all
phases of a flight, which I do routinely) will result in a one-way
ticket to kingdom come?

Geez, what a TWERP! You can't add two and two without jumping to
conclusions! A rational conversation with you is nearly impossible.

Getting back to the original question (poor to non-existant AM
reception), I understand the idea of aperature and long wavelenths of
AM radio and the size of airplane windows - but what about the effect
of ALL the windows on a plane? Don't they create a much larger
effective apperature when you consider all of them? And since the
plane isin't grounded, isin't the exterior shell of a plane
essentially transparent to all RF (ie it's just a re-radiator) because
it's not at ground potential?

You're even dumber than I had thought. Look up Faraday Shield.
Here, try this: http://www.physlink.com/Education/AskExperts/ae176.cfm
You don't have to worry about a ground for it to work. Duh.