When I first moved into my house, I noticed that the previous people had erected an extra TV aerial on a tall metal mast on the back part of the building. I don't use it, so the socket inside the house isn't connected to anything.

Naturally that suggested to me that I should make a crude field strength measurement by touching one multimeter probe to my hand, and the other to the centre pin of the socket. Indeed I did this on several occasions and generally found an AC voltage of about 1.9V .

Last night I was woken up at 2.30 by a massive thunderstorm, and immediately had the idea of measuring the voltage and seeing if it was different. I judged that I was unlikely to be killed as the mast is by no means the tallest metal object within a radius of its own height (also, if it was struck, I'd probably be killed by falling masonry even if I wasn't holding a metal probe connected directly to the aerial).

I was pleased to find that the voltage was indeed slightly higher - 2.6V .