Dear Laurence,

Thanks for your post.
>  (Its got a bit of MF in it honest) 
Whether it has or not, it could save one of our lives some day!

A friend who worked for the London Electricity Board years ago told me a 
similar story about working on 3-phase underground cables. You disconnect both 
ends, then before you touch them you short each phase to earth. Rarely will you 
have happened to disconnect at the zero-volts part of the cycle, so apparently 
you get some satisfying bangs.

But that may not completely explain your recent experience. One would guess 
that (a) you turned off the Tx before unplugging the aerial and (b) the Tx has 
a DC path across the aerial socket (e.g a transfo secondary). So did some other 
process charge up your cable?

Your experience might suggest that, for those who fiddle with their aerials 
frequently, it might be worth permanently fitting a resistor (100k, say) across 
the two halves; or two, one from each pole to earth.


73,
Chris G4OKW