The second one Rod.

Several phones left on would be a big safety issue as there would be , say 8 signals going off , for only 4 phones , 200 if all passengers left phones on !Try at home putting as many phones at hand near a radio & listen for the result.Most of the airband signals from /to the plane are related [harmonics] to cell phone frequencies. Probably near 200 watts ,total power if all passengers used their phones within 10 meters of the avionics.Must have some issues.

And where did we glean that gem of incorrect information from? :eek:

"The laboratory results indicated that the phones not only produce emissions at the operating frequency, but also produce other emissions that fall within airplane communication/navigation frequency bands (automatic direction finder, high frequency, very high frequency [VHF] omni range/locator, and VHF communications and instrument landing system [ILS]). Emissions at the operating frequency were as high as 60 dB over the airplane equipment emission limits, but the other emissions were generally within airplane equipment emission limits. One concern about these other emissions from cell phones is that they may interfere with the operation of an airplane communication or navigation system if the levels are high enough.....see..."http://www.boeing.com/commercial/aeromagazine/aero_10/interfere_textonly.html...and some basic amateur radio stuff re harmonics i first encountered in the 60s which still applies today....http://www.arrl.org/files/file/Techn...age/Hallas.pdf.

Danny, you forgot to add the "Bazinga" at the end :p

It's a funny policy "... radio transmission..." a GPS is a receiver, not a transmitter. Same as having a phone in "Airplane Mode".

I would guess people take one on board to see where they are and what speed they are doing... all a bit of fun.