My previous reply at no.7 above
"Hi Paul,
With just the standard supplied little mag-mount, (mounted on a redundant Peugeot brake disc!) albeit on top cliffs (200', 65m) at Mullion Cove, I was regularly getting up to 350NM (A/C at FL 400) distance. and if I can get my wife's redundant lap-top working, I'll be keeping that on 24/7/365 feeding to the network. CGJon"
That is with an absolutely clear horizon over the sea (Atlantic Ocean actually!), but I do feel there may be an element of ducting, but certainly not "skip" or "lifts" as experienced at much lower frequencies, what do others think? I must mention that using the supplied antenna outside on a regular basis is against the advice of the manufacturers, AN and W&S plc., but I modded and made mine as water-resistant as possible - 99.9% for longevity, but could do with just a replacement steel (preferably stainless, so it doesn't corrode at all) element which are not available - only supplied as a complete replacement antenna.