Lens question

"nospam" wrote in message
...
In article , No spam please
wrote:

As I said
earlier, a friend who operates an airfield radio found that her own radio
receiver upset the aircraft's systems.

but you didn't say how she determined that. did she turn on the radio
and the plane suddenly dive or make a sudden turn? how did she rule out
some other effect?

As I understand it, the pilots found a malfunction and asked cabin crew to
see if anyone was using a radio receiver or transmitter. I don't know the
aircraft type.

Regards, Rog.

"John Navas" wrote in message
news
On Mon, 2 Nov 2009 17:00:53 -0000, "No spam please"
wrote in :

I believe that the fuselage is a Faraday cage so it will alleviate
interference from outside the aircraft ...

RF signals can and do penetrate windows.

--
Best regards,
John

Hello John.

Yes, RF signals can penetrate windows and there is a relationship between
the size of the window and the wavelength of the RF signal. This is why
Faraday screens designed to stop 50Hz or 60Hz mains radiation can be made
from wire grid instead of solid metal.

Regards, Rog.

"Dudley Hanks" wrote in message
news:RSIHm.50288$Db2.19440@edtnps83...

"No spam please" wrote in message
...
"Dudley Hanks" wrote in message
news:Q2CHm.50238$Db2.18755@edtnps83...

" "Mister, at this time you are required to turn off your pacemaker.
When we reach 10,000 feet, you may re-start it. Thank you."


George, that's about as good a way of encapsulating the issue as I've
read...

Take Care,
Dudley


Hi guys.

Nice analogy but the wrong way round. When you visit a radar site or
broadcast site you should see signs warning those with pacemakers not to
enter. Pacemaker is the victim, not the perpetrator.
An acquaintance of mine works in the world of radio but can't accept site
visits to broadcast sites because of his pacemaker.

Best wishes, Rog.


Not really, I think George was lampooning the practice of turning off ALL
electrical devices during take-off and landing. Followed too strictly,
nasty things would happen...

Take Care,
Dudley

Hello Dudley.

Ah - I see what George meant. Thanks for explaining it to me. My guess (I
may be able to check with a retired medical electronics technician) is that
pacemakers are well designed with regard to interference to/from them
because they have to work in hospital theaters and ICUs.
Personally, I want to keep as far away from pacemakers as possible. Hope the
same applies to you and George.

Kindest regards, Rog.

In article , No spam please
wrote:

As I said
earlier, a friend who operates an airfield radio found that her own radio
receiver upset the aircraft's systems.

but you didn't say how she determined that. did she turn on the radio
and the plane suddenly dive or make a sudden turn? how did she rule out
some other effect?

As I understand it, the pilots found a malfunction and asked cabin crew to
see if anyone was using a radio receiver or transmitter. I don't know the
aircraft type.

malfunctions can occur for a variety of reasons. that's not proof that
the radio was the cause.

"John Navas" wrote in message
...
I recall reading a book documenting a 747 flight over the pond. When one
of
its radio transmitters was used then one of the fuel gauge sensors lost
track of how much fuel was in the tank.

I don't see how that is any way relevant.

I know that my cordless landline phone upsets my FM radio - not when I'm
talking over the phone but when it is being charged.

Your FM radio is cheap junk compared to aircraft systems.

--
Best regards,
John

Hello again John and thank you for the posting.

I'd better clarify the comment about the 747.
If one system on the aircraft (the fuel gauge system) was not immune to
intererference from another system on that aircraft (the radio transmitters)
then why should we expect any immunity from electronic systems brought on
board by passengers?

Regards, Rog.

nospam wrote:
In article , No spam please
wrote:

As I said
earlier, a friend who operates an airfield radio found that her
own radio receiver upset the aircraft's systems.

but you didn't say how she determined that. did she turn on the
radio and the plane suddenly dive or make a sudden turn? how did
she rule out some other effect?

As I understand it, the pilots found a malfunction and asked cabin
crew to see if anyone was using a radio receiver or transmitter. I
don't know the aircraft type.

malfunctions can occur for a variety of reasons. that's not proof that
the radio was the cause.

How about if turning it off fixed the problem and turning it back on
resulted in it returning?

In article , J. Clarke
wrote:

malfunctions can occur for a variety of reasons. that's not proof that
the radio was the cause.

How about if turning it off fixed the problem and turning it back on
resulted in it returning?

how about controlled tests, many of which have been done and none of
which have found any link. and in this particular case, the radio was
not turned back on to see what happened.

"No spam please" wrote in message
...
[]
I'd better clarify the comment about the 747.
If one system on the aircraft (the fuel gauge system) was not immune to
intererference from another system on that aircraft (the radio
transmitters) then why should we expect any immunity from electronic
systems brought on board by passengers?

Regards, Rog.

Rog,

It's because interference to a non-radio system from a transmitter is most
likely to be due simply to the field-strength of transmitted signal, than
to its exact frequency or modulation type. I.e. the signals emitted by a
non-transmitting consumer electronic system are of a much lower field
strength. There is probably no sensitive radio receiver in the fuel gauge
system. That's why it's a reasonable expectation - in general. I should
add that I don't know details of the specific systems involved, though,
I'm talking in general.

David