[Milsurplus] ADF today

[KD7JYK DM09]

"A group of hams operating a navigation aid for fun?   That would work 
until the first aircraft crashes because the NDB calibration was only to 
"Ham Standards"......."

You're thinking GPS.  An NDB puts out a signal, in a region.  It's no 
more accurate than a local broadcast station, in a region.  The extent 
of using an NDB in an aircraft is...  "Signal, thataway-ish...".

There are DGPS signals, also in the LW range, those work in conjunction 
with 1.5 GHz GPS, and add an extra signal source for some corrections, 
but that is entirely different than NDBs which just spew out a carrier 
with a Morse code ID.

Kurt