That would be an Adcock Range or 4 course range. The NDB is
just a radio station that is used by the ADF as a source for
the directional loop antenna to point to.
BTW, it was .- and -. (A and N) and when on course all you
heard was a steady ____________

You flew a little to the side of the leg and thus hear a
steady tone with a slightly audible A in the background.
There was even a reed needle that could be panel ,mounted
and would vibrate. That was high tech in 1940.



--
James H. Macklin
ATP,CFI,A&P

"Robert M. Gary" wrote in message
ps.com...
| You have a NDB at KTTD!
|
| What's an NDB? Is that that thing that sends "dot, dot,
dot" on the
| right side and "di di di" on the left side??
|
| -Robert
|