Barkly1992 I am passing a message from Mr FBW, he is asking if you please clarify which part of the circuitry of an MP3 player emitts RF and what frequency and what magnitude.
He's very interested as he's a skipper himself and none of our manuals say anything about it.

And something from me just out of curiosity....did you really have MP3 players in Oz back in the 80's?

Thank you :)

FBW

The usual radiating sources are the internal clocks. These can be anywhere, but there are advantages in having them in the 10 to 25MHz region - cost of crystals, power consumption. They produce harmonics at multiples of the clock frequency, and get divided down to lower frequencies, which also get radiated, and the lower frequencies can get into NDB receivers. The higher frequencies get modulated by the lower ones, so it's not a nice clean frequency, but a whole slew of them. In order to met the few standards there are, one trick is to 'dither' the frequencies, which effectively spreads them out but raises the whole noise level. An analogy is having a pile of manure in one corner of a field that stinks out that area as opposed to spreading it over the whole field and stinking out the larger area at lower intensity.....
You may well find that some MP3 players don't emit, and others do. That makes it very hard to draw a general conclusion. Add to that the susceptability of aircraft systems, especially as aircraft age and the effectiveness of ground connections on shields and so on decreases, and abrasion gets at cables and so on.
The CAA comments to me were related only to hearing aids operating in the 800 -900 MHz region, with output powers below 10 nanowatts, by the way.

With a callsign like "Flybywire" I would have thought that you knew all about this subject.

However, it was not ME that said that MP3 players caused difficulties with airline nav and control systems. It was others - if you looked at what I had to say I was questioning that MP3 players were an issue - laptops - mobile phones - pacemakers as well. I was saying that lawyers were the problem.

I love skippers BTW - they are captains that are actually older than me.

And also BTW - in the 1980s and 1990s we had many devices which generated RF - not MP3 players I agree - many other devices which emitted lots of RF - including vibrators.

:cool:

I take the banter, believe it or not I am indeed a musician, I know all about other frequencies (Acoustics is my field) but know little about RF and their applications nowadays.

forgive me, I read this...

...and I didn't take the sarcastic tone. Sorry!

I did think that MP3 players indeed transmit some sort of RF but these are minimal. Even our bodies have some kind of low electrical activity (eg. brain and indeed the heart, I used to hate ECGs!!).
In my humble knowledge of this subject I have always thought that MP3 players were somehow safe as the RF transmitting part should indeed be protected by some sort of "cage" anyway.

hahahaha! I won't tell him that then!!! He'll be first-time daddy in a few months and he would be gutted to be told that he's THAT old ;)

:E reminds me of an incident....having to tell one of my passengers if she could switch off her vibrating bag in the overhead locker for take-off please......embarassing? Not at all, the funny part was actually witnessing the businessmen sitting next to her starting to sweat uncontrollably!!! :E

FBW

Radeng thank youvery much for taking the time to reply to me, I really appreciate that :)