Blast from the past
Not that I've looked lately, but I think I've still got mine on 'Athene of Lymington' (can't look right now 'cos she's sitting on the concrete in Preveza, Greece). Brings back memories of navigating 'on the null' rather like the 'Neckerbein' used by the Nazi bombers in WWII. Not that I always hit the target, of course, as my crew can attest.
The marine stations are long gone, but as far as I know the aero beacons used for aircraft navigation are still broadcasting. You just need to know the frequency, tune the Lokata 7 to it, then swing from side to side and wait for the null, which gives you the bearing (I assume you have the plug-in headphones as well). You obviously need at least three bearings to give a reasonably accurate fix, which may be the problem these days.
Anyway, if that doesn't work you can always go back to the cross staff ...
Athene of Lymington
: Albania, France, Spain, Portugal, Croatia, Italy, Montenegro, Greece, Turkey, Gibraltar, Sicily, Corsica, Sardinia