[ARC5] NDB useful range ?

[Hubert Miller]

Swan Island: when I was in high school, I got a QSL from 'Radio Americas', I think it was called,
which was an anti-Castro shortwave station with transmitter on Swan Island. It had a hand-written
notation on it, "6100 kcs is too far off for a QSL from me", kind of a joke by the signer, but of course
my Lafayette receiver did not have 1 kHz readout, or even 100 kHz. Some years later, in a mistaken
purge, I tossed all my QSLs, something I really regret today. But maybe 30 years later, in a bookstore
in downtown Seattle, I actually found a Radio Americas QSL for sale - no way to resurrect my original,
but still a lucky find. 
( My friend Greg says Seattle area where he works is largely boarded up windows defaced by graffiti. 
"Power to the People", right? ) 

Aircraft ADFs: those I find very interesting. But due to low production numbers, I suppose, the service
manuals can be very expensive, and it seems prohibitive to try to get a collection of those together.
-Hue Miller