14-09-2017, 12:49 PM
This is pure guesswork, Mike, but could work.
The mains earth is a long wire running round the house in very close proximity to the live wire. The earth wire must have some inductance which, while it doesn't affect its function of conducting fault currents to ground, with have an impedance to earth for all RF interference injected into it - primarily, I would expect, from the adjacent live wire.
If your new earth is effective, if you take a second wire from the earth rod itself and connect that to the mains earth in the house, any interference on the mains earth will be conducted directly to earth and not appear on your new receiver earth wire.
However, there may still be a common connection if both earths share the same physical path from the house, so it might be worth using a length of coax for this section, connecting both centre conductor and screen at the earth rod but only the centre conductor at the house end. The woven screen should have a low impedance to any interference picked up on it and, of course, you will now have two capacitors in series between the two earths which will also reduce any pickup.
It might also be worth stripping the outer sheath off the coax and ensuring that it is bedded well down into the soil beneath the concrete.
Worth considering?
The mains earth is a long wire running round the house in very close proximity to the live wire. The earth wire must have some inductance which, while it doesn't affect its function of conducting fault currents to ground, with have an impedance to earth for all RF interference injected into it - primarily, I would expect, from the adjacent live wire.
If your new earth is effective, if you take a second wire from the earth rod itself and connect that to the mains earth in the house, any interference on the mains earth will be conducted directly to earth and not appear on your new receiver earth wire.
However, there may still be a common connection if both earths share the same physical path from the house, so it might be worth using a length of coax for this section, connecting both centre conductor and screen at the earth rod but only the centre conductor at the house end. The woven screen should have a low impedance to any interference picked up on it and, of course, you will now have two capacitors in series between the two earths which will also reduce any pickup.
It might also be worth stripping the outer sheath off the coax and ensuring that it is bedded well down into the soil beneath the concrete.
Worth considering?
