gzt: How much RF stuff do you have in that cabinet/closet

RUKI: My two cents:
- Have electrician tested inside distribution board where your earth is connected to neutral? Checked loose contacts, etc? If they only looked outside the house - earth may well be in good condition outside, but they also need to check inside (FYI - if you own the house - read electrical code of what you can do - many things are allowed to the house owner).
- Does your power bill look abnormally big? (>$120Ave) There were two reports from my friends who experienced above average power bill at their premises (e.g. up to $600/month) - service company followed by testing and revealed some [earthing] issues;