Ian Jackson wrote:
In message , D
Peter Maus writes
Ian Jackson wrote:
In message , dave
writes
Ian Jackson wrote:
In message , Brenda
Ann writes

wrote in message
...
Heading to Hawaii this Christmas and thinking
of taking a Sony 2010 --
Any hassles or obvious tips I could use?

Thanks!

Other than don't turn it on during the flight.. should be no
problems. Best
to pack it in your checked luggage.

Some airlines DO (or, at least, did) allow the use of radio
receivers during flight. Virgin is one of them. It may be worth
asking. It's interesting to note that, when you travel from the UK
to Florida, the first language you are likely to hear on the FM
B/C, the USA, is French.
I don't know any airline that allows AM/FM radio use at any time.
The LO on many FM radios causes radiation in the Navigation band.
Trust me, a few years ago, Virgin definitely did allow the use of
radio receivers. It was on the list, along with PCs, calculators,
electronic games etc. Without a doubt, the top end of the FM B/C band
+ 10.7MHz does put the LO in the air traffic control band. However,
in practice, it's difficult enough to get even FM signals inside the
(you have to have a window seat). Even at ~100MHz, the windows are
still a bit on the small size. So, I doubt if a relatively weak LO
at 120MHz is unlikely to have much impact on the ATC communications.
Those guys don't really go in for weak-signal communications.


It's not likely to prevent comms, but it can put a heterodyne on top
of comms. Which, in a cockpit, on approach in high traffic areas, can
be a major distraction.

Oh, I agree, it could put a heterodyne on top of comms (especially as
they are AM) - and possibly a very unstable one at that. But, as I said,
those guys don't really go in for weak-signal communications.


It doesn't have to be a weak signal comm for a heterodyne to be a
problem.


One of the reasons AM is still used for AV com is to avoid the
capture effect of FM. If there are two comms on the same channel, a
heterodyne lets a pilot, ATC, or Center, know that they're both out
there. An unstable heterodyne on top of or even underneath comms in the
cockpit in an active traffic area can behave as, or mask, the existence
of an actual comm--potentially an emergency situation.


Consider also, that AVComm modulation levels are all over the place.
ATIS at Gary is often so soft as to be unreadable, even when signal
strength is high. A very weak heterodyne originating on the aircraft
would severely compromise ATIS reception, which is a precursor to the
first radio call.

I'm a photographer on a good day, specializing in aerial. And I spend
about 2 days a week hanging out of a JetRanger with my Nikons.

I monitor traffic with the pilot, and trust me when I tell you, in
the Chicago area, a heterodyne on the comm channels is a highly common
occurrance. A heterodyne originating on the aircraft would create a
distraction that a pilot in traffic simply can't afford.

As for Virgin's findings...there's a difference between negligible
and zero.

It only takes ONE convergence of improbable circumstances to create a
real hazard in the air. You don't play odds, here.







Presumably
Virgin did an assessment of the risk, and decided it was negligible.