My 2 bits, an a guess, for what its worth:

At a college where I taught many years ago, we had a blind student who
would get his computer 'output' via an FM radio on the console, with the
program set to loop at various frequencies for a dot and a dash, and he
could listen to the output in morse code (he was also a ham radio operator).

The FM radios are the main culprit in aircraft, since most directional
headings are based on VOR signals that occupy many MHz just above the FM
band, where the local oscillator of the FM radio sits, typically 10.7 MHz
above the station being received.  The signal only has to be nearby in
frequency to mess up the VOR signal.  The VOR XMTR is not high powered (20
to 50 watts), and may be 50 miles away, whereas the FM receiver is maybe
only 1 milliwatt but 50 feet away!  The direction signal is transmitted as
a phase difference between a low frequency audio tone and the same
frequency audio tone modulated onto a 10 KHz carrier.  By comparing the
phase difference, you can tell the direction in degrees from North that you
are from the transmitter.  It is real easy for an FM radio local oscillator
hetrodyne to mess this up.

When the pilot in an airliner refers to his Directional Gyro, he is really
refering to a more modern and complex device called an HSI (horizontal
situation indicator).  This instrument shows you gyro heading alright, but
it also shows you (with a needle) how much you are to the right or left of
course, and the pilot may simply have calculated a 20 degree or more
correction in order to get the needle to center.  Keeping the needle
centered, he thinks he is just correcting for wind, while his actual
heading is quite wrong.  I am guessing that this is why he refered to the
DG the way he did in the report. (yep, i'm a pilot, fly my own plane).

In our FCC testing for class A/B, we keep an old Toshiba 286 plasma panel
laptop around with a metal (I think magnesium) case  -- it is super quiet
in the RFI department, and we can test our boards, external adapters, etc.
in an otherwise quiet RF environment.


Regards,
  Ron Fial