The radiation from laptops, which is considered to be harmful enough,
is broadband, so the signal on any given frequency won't be terribly
strong.  But the local oscillator in your broadcast FM radio is
usually 10.7 MHz higher than the frequency you tune to; namely it
will run from 98.7 to 118.7 MHz as you tune across the FM broadcast
band.  The Instrument Landing System localizer transmitters are
between 108-112 MHz.  (30 years ago I did front end design for a
Collins ILS receiver).  VOR transmitters are between 112-118 MHz, I
think.  The discrete local oscillator frequency from an FM radio is a
lot stronger than the broadband hash from a laptop.  In the future,
leave that thing turned off!

The airphones, although a money-making proposition, are also a known
quantity.  The FAA and airlines know what these units do and don't
radiate, and on what frequencies; they therefore have been
coordinated.  I think they are on a lower band than cell phones, but
I'm not sure.

On Mon, 14 Jan 2002 11:38:50 -0500, JEFFREY MICHAEL KENYON wrote:

>Well, if they want to be so strict about even listening let's ban lap tops
>that transmit and many user manuals expressidly say that they do emit
>RF.  Also, ban the seat phones which charge through troof rates.
>
>
>
>
>
>On Mon, 14 Jan 2002, Walt Smith wrote:
>
>> Jeffrey -
>>
>> The point isn't that some device ... a laptop, for example ... is a
>> radiator, per se.  The point is that specific devices are _designed_ to
>> radiate in very specific frequency ranges and those have the potential for
>> head-on collisions with avionics.  Don't argue with the rule, just observe
>> it ... you're an FCC licensee and should be used to this concept.  I haven't
>> seen any hams trying to challenge this FAA regulation before the FCC, which
>> I interpret as fairly sound proof that it's a good rule.
>>
>> --
>>  Walt Smith - Raleigh, NC
>>  [log in to unmask]
>>

Braille is the solution to the digital divide.
Lloyd Rasmussen, Kensington, Maryland
home:  <[log in to unmask]> <http://lras.home.sprynet.com/>
Work:  <[log in to unmask]>         <http://www.loc.gov/nls/>