AM radio reception inside passenger planes?

S

Some Guy

Guest
I have no trouble receiving FM radio broadcasts on a small am/fm radio
I sometimes listen to while onboard commercial jet airliners (flying
at cruise altitude), but I never seem to be able to pick up AM radio
stations. It's just static across the AM band.

Any explanation for this?
 
Any explanation for this?
Click to expand...
FM radio generally operates at longer range than AM radio, however it's
limited to line-of-sight. However, when you're 40,000 feet up you can "see"
a lot of transmitters hence the FM signals.

Cheers,
Geoff Glave
Vancouver, Canada
 
"Geoff Glave" <nospam@nospam.com> wrote in message
news:HxHud.9448$eb3.8331@clgrps13...
Any explanation for this?

FM radio generally operates at longer range than AM radio, however it's
limited to line-of-sight. However, when you're 40,000 feet up you can "see"
a lot of transmitters hence the FM signals.

Cheers,
Geoff Glave
Vancouver, Canada
Click to expand...
I reckon you just answered the wrong question !!

The reason A.M. radio can not be received in a plane is that it is a Faraday
cage to the (lower frequency) A.M
frequencies, whereas the VHF frequencies can just about get through the
windows.

There may be a bit of frequency / range issue as well but top band and 80 mtrs
gets across the pond so
I don't think this is the issue here...

Nick
 
In message <piIud.4676$ve.1869@fed1read06>, Ether Hopper <EH@skip.net>
writes
No one has mentioned that in many cases you need the pilot's permission to
operate a radio or other electronic device for that matter on a commercial
airliner. That includes AM/FM radios.

Radio emissions may screw up the plane's avionics.
Click to expand...
Virgin included the use of radio receivers in their 'permitted list'
about 3 years ago. However, I do wonder about the use of the FM
broadcast band because the LO (tuned freq + 10.7MHz) can land up right
on top of something important in the ATC band.
Ian.
--
 
"Some Guy" <Some@guy.com> wrote in message news:41BB8C6A.FD42C1E7@guy.com...
What a load of horse shit.
Click to expand...
Yes, you are a wholesale distributor. Further, you are a loud-mouthed,
egocentric nitwit with a knowledge of physics equivalent to a smart gerbil.
You should be allowed on an aircraft only as freight.

Ed
wb6wsn
 
On Sat, 11 Dec 2004 22:23:47 -0500, "Dave VanHorn"
<dvanhorn@dvanhorn.org> wrote:

|
|> So, in all honesty, YOU can't really say how dangerous operation of an FM
|> receiver will be; but you KNOW that it's potentially harmful.
|
|Given that the aircraft voice comms are just above the FM BCB, and the
|typical first IF is 10.7 MHz, it's not too hard to imagine the LO sitting
|right on the tower comm frequency.
|You may only radiate a microwatt, but you're much closer to that antenna on
|the aircraft than the tower is. Inverse square law makes it very easy for
|you to win that contest.

Correct. Let me offer a slightly different but illustrative example.

Since this is cross-posted to some non-ham groups, bear with me. In
the 1960's I operated my amateur station on the two-meter (144 MHz)
band using several hundred watts of AM and directional antennas.

I'm in Tucson where we have both a commercial airport and D-M AFB. An
acquaintance of mine, also a ham, was the FAA tower chief at Tucson
International.

One day he calls me on the phone and says that the tower guys at D-M,
knowing he was a ham, called him first rather than the FCC, to report
that I was interfering with their tower communications.

To make an involved detective story short, it turned out that another
ham, who lived just outside the AFB was using a Heathkit "Twoer". The
Twoer used a super-regenerative receiver and was picking up my signal
and re-radiating it on the tower frequencies. I was getting blamed
for the other guy's illegal transmissions.

Considering that this technology is probably used in more receivers
today than any other type (garage door openers, computer wireless
links, etc.) if I'm flying, I hope they are all turned off.

|
|This is a pointless argument though. It's a health and safety issue, and
|you either follow the airline's rules, or I hope they boot you off the plane
|(optionally, landing first for your convenience) It is just that simple.
|
 
Pitot tube at URL;
http://www.grc.nasa.gov/WWW/K-12/airplane/pitot.html

Re Pitot Heat -- see URL:
http://www.allstar.fiu.edu/aero/PSSI.htm


Sez
The system shown employs a heated pitot tube to prevent ice formation, a
necessary feature for flight in instrument conditions.
--
ID with held to protect the innocent


What is a Pitot tube anyway? I have seen a switch for most aircraft
in Flight Simulator marked "Pitot Heat", what is that?
Click to expand...
 
Well, I'll be flying to philly again tuesday.
My dualband HT goes in my breifcase, but with the battery detached during
flight.
 
"Dave VanHorn" <dvanhorn@dvanhorn.org> wrote in message
news:1-udnYjM7_OYUSHcRVn-sA@comcast.com...
Well, I'll be flying to philly again tuesday.
My dualband HT goes in my breifcase, but with the battery detached during
flight.
Click to expand...
The first note of personal responsibility and common sense yet seen in this
thread. Congratulations!

Ed
wb6wsn
 
"Ed Price" wrote:
...
Stick to assertions that
have a basis in fact and not just in your mind.
...
Fred, your world is much different than any I have ever seen.

Ed
wb6wsn
Click to expand...
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.
 
Reception of radiosignals inside a Faradaycage is limited to frequencies
that are smaller then the holes in the cage.
"Geoff Glave" <nospam@nospam.com> schreef in bericht
news:HxHud.9448$eb3.8331@clgrps13...
Any explanation for this?

FM radio generally operates at longer range than AM radio, however it's
limited to line-of-sight. However, when you're 40,000 feet up you can
"see"
a lot of transmitters hence the FM signals.

Cheers,
Geoff Glave
Vancouver, Canada
Click to expand...
 
cabin. But has anybody ever heard a cabin announcement during flight
to turn off any devices?

Fred F.
Click to expand...
There have been numerous postings in various scanner, shortwave and ham
groups by people who have been ordered to turn off their radio and other
PEDs.
More than one person has been ordered off, or met by the authorities on
landing and at least one passenger who refused to turn off a cellphone ended
up with some jail time after landing in the U.K. - it was pretty widely
reported a year or so ago.

Dave
 
And you do want the Avionics to work properly don't you ???

--
RF Gotta Go SomeWhere



"Ether Hopper" <EH@skip.net> wrote in message
news:piIud.4676$ve.1869@fed1read06...
No one has mentioned that in many cases you need the pilot's permission to
operate a radio or other electronic device for that matter on a commercial
airliner. That includes AM/FM radios.

Radio emissions may screw up the plane's avionics.

See URL:
http://www.fordyce.org/scanning/scanning_info/scan_fly.html

It sez:
"The FAA does not allow inflight use of walkie-talkies, radio controlled
toys, AM/FM radios, portable telephones, or portable television sets, all
of which may affect aircraft radio and navigation equipment"

Also cruise ships may deny use of two way (FRS) or ham radios -- always
check with the communications officer.

For Hams always check with the person in charge on any commercial
transportation, busses, taxi's, ships planes etc.

Yeah yeah I know you did it without getting permission, but read the URL
as to what airlines have published.

And I know from personal experience that some cruise lines do not allow
FRS or ham radios transmissions.

--
RF Gotta Go SomeWhere



"nick smith" <NickS@ntlworld.com> wrote in message
news:MZHud.680$Uh.421@newsfe1-win.ntli.net...

"Geoff Glave" <nospam@nospam.com> wrote in message
news:HxHud.9448$eb3.8331@clgrps13...
Any explanation for this?

FM radio generally operates at longer range than AM radio, however it's
limited to line-of-sight. However, when you're 40,000 feet up you can
"see"
a lot of transmitters hence the FM signals.

Cheers,
Geoff Glave
Vancouver, Canada



I reckon you just answered the wrong question !!

The reason A.M. radio can not be received in a plane is that it is a
Faraday
cage to the (lower frequency) A.M
frequencies, whereas the VHF frequencies can just about get through the
windows.

There may be a bit of frequency / range issue as well but top band and 80
mtrs
gets across the pond so
I don't think this is the issue here...

Nick
Click to expand...
 
"Geoff Glave" <nospam@nospam.com> wrote in message
news:HxHud.9448$eb3.8331@clgrps13...
Any explanation for this?

FM radio generally operates at longer range than AM radio,
Click to expand...
Nonsense! AM radio stations can be heard for thousands of miles, FM for
'line of sight', which is usually less than a hundred miles.

however it's
limited to line-of-sight. However, when you're 40,000 feet up you can
"see" a lot of transmitters hence the FM signals.
Click to expand...
Nonsense! The passenger is sitting in a Faraday Cage, a fuslage made of
alumninum. The FM wavelength is short enough to go thru the windows,
but mot the AM signals.


Cheers,
Geoff Glave
Vancouver, Canada
Click to expand...
 
"Ian Jackson" <IanJacksonRemoveThisBit@g3ohx.demon.co.uk> wrote in
message news:QQZkixB8u0uBFwNV@g3ohx.demon.co.uk...
In message <HxHud.9448$eb3.8331@clgrps13>, Geoff Glave
nospam@nospam.com> writes
Any explanation for this?

FM radio generally operates at longer range than AM radio, however
it's
limited to line-of-sight. However, when you're 40,000 feet up you
can "see"
a lot of transmitters hence the FM signals.

Cheers,
Geoff Glave
Vancouver, Canada



The window holes are much too small to let the much longer wavelengths
of the 'AM' signals through. The body of the plane is a very effective
screen. The 'FM' signals can squeeze in, but it helps if you have a
window seat. I've also listened to SW in the middle of the Atlantic.

Flying from the UK to Florida, on the other side of the Atlantic the
first FM stations you hear are usually speaking French (from Quebec)
It's quite alarming!
Ian.
--
Click to expand...
If you stretch a string on a globe from London to Florida, it will show
the 'great circle' route that's the shortest, and that should be your
plane's path, barring storme, hurricanes, etc. You'll see that it comes
really close to the eastern Canadian provinces.
 
cup shredded cabbage
1 cup bean sprouts
5 sprigs green onion, finely chopped
5 cloves minced garlic
4-6 ounces bamboo shoots
Sherry
chicken broth
oil for deep frying (1 gallon)
Salt
pepper
soy & teriyaki
minced ginger, etc.
1 tablespoon cornstarch dissolved in a little cold water
1 egg beaten

Make the stuffing:
Marinate the flesh in a mixture of soy and teriyaki sauces
then stir fry in hot oil for till brown - about 1 minute, remove.
Stir-fry the vegetables.
Put the meat back into the wok and adjust the seasoning.
De-glaze with sherry, cooking off the alcohol.
Add broth (optional) cook a few more minutes.
Add the cornstarch, cook a few minutes till thick,
then place the stuffing into a colander and cool;
2 hours
Wrap the rolls:
Place 3 tablespoons of stuffing in the wrap, roll tightly -
corner nearest you first, fold 2 side corners in,
wrap till remaining corner is left.
Brush with egg, seal, and allow to sit on the seal for
a few minutes.
Fry the rolls:
325° if using egg roll wraps, 350° for spring roll wraps.
Deep fry in peanut oil till crispy golden brown, drain on paper towels.



Lemon Neonate

Turkey serves just as well, and in fact even looks a bit like a
well-dressed baby. By the time you turn the child?s breast into
cutlets, it will be indistinguishable. The taste of young human,
although similar to turkey (and chicken) often can be wildly
different depending upon what he or she has consumed during its
10 to 14 months of life...

4 well chosen cutlets (from the breasts of 2 healthy neonates)
2 large lemo
 
"Julia Child" <Iron.Chef@cooks.r.us> wrote in message
news:41D16E75.CAB91711@cooks.r.us...
What's with all the recipe bullshit posts?

Who's posting these?

Ed Price wrote:
Click to expand...
SNIP

No, I didn't write that. However, "Julia", rest assured that, by posting
your question, your address will soon be harvested for use by the Hipcrime
bot in the DOS attack. Don't reply, don't post about it, don't help the bot.

Ed
wb6wsn
 
On Wed, 29 Dec 2004 16:44:01 -0800, "Joel Kolstad"
<JKolstad71HatesSpam@Yahoo.Com> wrote:

Why is an AM/FM radio receiver potentially more dangerous than laptop PCs,
gameboys, DVD players, and other electronic devices that are used quite
routinely on airplanes?
___________________________________________________________
Click to expand...

For one thing, they have an antenna which can transmit as well as
receive, although poorly compared to a *real* antenna. How much
radiation depends on the design of the radio. A cheapo one could be
pretty bad.

--
Bill, W6WRT
 
"Joel Kolstad" <JKolstad71HatesSpam@Yahoo.Com> wrote in message
news:_N-dnfB8FZVo3kHcRVn-sA@comcast.com...
"Dave VanHorn" <dvanhorn@dvanhorn.org> wrote in message
news:MtidnfyW_MfQ507cRVn-ow@comcast.com...
The other devices may have circuits that incidentally radiate a little
noise in the aircraft VHF band.
A broadcast FM receiver almost certainly has an oscillator running by
design, in the band.
Where it lands in the aircraft band, is determined by where it's tuned
to.

Ah... you're thinking... FM broadcast range is 88-108MHz... with a 10.7MHz
IF... a high side LO is at ~98-118MHz, easily landing within the aircraft
band (which is... 108-??? MHz, right?).



The original poster is long gone -- refused any info and advice we gave him
Click to expand...
including a list of airlines that prohibit AM/FM radios and other devices
And the FAA stance on the matter
Must have been 50+ responses
So I guess we can put this to bed



--
Caveat Lector
 
In message <HxHud.9448$eb3.8331@clgrps13>, Geoff Glave
<nospam@nospam.com> writes
Any explanation for this?

FM radio generally operates at longer range than AM radio, however it's
limited to line-of-sight. However, when you're 40,000 feet up you can "see"
a lot of transmitters hence the FM signals.

Cheers,
Geoff Glave
Vancouver, Canada
Click to expand...
The window holes are much too small to let the much longer wavelengths
of the 'AM' signals through. The body of the plane is a very effective
screen. The 'FM' signals can squeeze in, but it helps if you have a
window seat. I've also listened to SW in the middle of the Atlantic.

Flying from the UK to Florida, on the other side of the Atlantic the
first FM stations you hear are usually speaking French (from Quebec)
It's quite alarming!
Ian.
--
 
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