Dear Gary, LF Group,

Quoting from the Propagation chapter of the Admiralty Handbook of Wireless
Telegraphy 1938 edition:

"It is usually observed that the different frequency components of a
modulated wave fade in a manner which is independent of each other. This has
been termed "selective fading"...
...The use of ICW ["interrupted continuous wave" i.e. modulated CW as with
the NDBs] at H/F is therefore a means of combating fading in telegraphic
work."

So  the idea of increasing the signal bandwidth to combat selective fading
is not entirely new... MCW beacons anyone?

Cheers, Jim Moritz
73 de M0BMU