In the past, I've presented you with a series of puzzle caches, several of which relate to various methods of transmitting secret messages.
The cache is located at:
Among these are A Three Pipe Problem (using the dancing men), Velcomen... Ja, Oofta (Nordic runes), Another One To Stump You (mirrored grille), Ah the joys of childish toys (the Playfair cypher). Other puzzle caches have depended more on your esoteric knowledge (or ability to do research), including The Final Problem (Sherlock Holmes) and Mother Goose Rhymes (nursery rhymes).
N 47 51.881
This time, however, I've chosen another significant method of transmitting a secret message ... except that you'll have to figure it out because I'm only offering one clue. (Suggestion, try not to refer to the hint ... even though it's not entirely a giveaway.)
W 122 50.600 ... or 50.608
Now, for my next ... well, there's positional notation, there's a book code ... humh, wonder how I could manage a microdot? I'll have to think about that one.
(bring your own pen)