Thank you all for supplying the information I requested. May I explain what
is going on?
Last weekend the British Cave Research Association's Cave Radio and
Electronics Group performed some tests in the Yorkshire Dales with a view to
finding, amongst other things, whether we could null out some of the
interference we experience with cave radios.
The principal source of interference is LORAN C (known in cave radio circles
as The Galloping Horses) but this of course is a somewhat variable signal .
We use MSF and DCF as more nearly constant signals for testing the
directivity of our surface arrays .
Our results should be published in the next issue of the correct a journal.
John Rabson G3PAI