[G8BBZ]

Baz4CQJ wrote:
"If I read it correctly, then it raises interesting questions for anyone who has a vertical aerial with a good ground radial system. It actually suggests that a radio amateur might consider having his house re-wired with a TT mains supply arrangement, though I thought that was against the trend and that safety considerations and the modern regs were pushing people away from TT. That's exactly what I was planning to do; have a new consumer unit installed and go from TT to PME, which the supply people confirm I can do."

The current trend towards PME (TN-C-S) wiring systems has nothing to do with safety and everything to do with cost.
TT systems applied at household level require an isolation transformer rated to carry the maximum household load of 15kVA - an item which will cost several thousand pounds. TT systems also require that the householder install and maintain an "installation earth electrode" to which exposed conductive parts of the installation can be bonded. Electricity suppliers are , perhaps rightly, concerned that this requirement may not always be satisfied, leading to possibly hazardous situations.
TN-C and TN-S systems require that the electricity supplier provide and maintain a earth system capable of providing a suitably low earth fault loop impedance to ensure the operation of protective equipment in any installation served by the supplier's sub-station. Again, a cost which the supplier would wish to avoid.
Creating a TT system within one room of a house to serve a radio installation is quite feasible, the "installation earth electrode" then being the same as the RF earth/tower earth etc. An isolation transformer is required but this need only be rated to provide the power for the station - perhaps 2kVA unless you run really big linears! Any parts of the general PME system in the room need to be disabled/blanked off and any exposed conductive parts like central heating pipework need to be made non-exposed.
I am lucky enough to live in a rural area where we are supplied by overhead line and the installation system is TT from a pole mounted transformer. While we perhaps see more voltage fluctuation from the overhead line supply than you would in an urban environment, the supply/earthing arrangement is electrically quiet - not that it helps much at the current state of the sunspot cycle.