I have to take significant difference with Clive Brittain on this one, simply because he does not appear to understand the difficulties with TT should there be other extraneous parts (such as central heating pipes or radiators, storage heaters etc.) in the shack. It is simple to TT an outbuilding but not part of an internal installation in a house. I think the worry about lost neutrals is excessive, there are many more serious significant dangers with high power radio equipment, and often much higher potentials available, as well as seriously dangerous RF potentials. The word shack does not mean shed, it is a technical term for the radio operating space! It is possible to TT the whole building installation, but this is not always wise where there are buried metal services which are extraneous to the building, or everything around the site is a TNC-S installation which must always be assumed. RCD protection in line with BS7671 2018, is suggested whatever the installation type. Unfortunately advice from average electricians about this kind of installation is very unlikely to be satisfactory, most struggle with normal TT installations in my experience. Items and the external earthing system may be separately bonded to an Earth marshaling terminal if desired in the shack, and thence to the MET. RF voltages on the house electrical system are very undesirable, and could be a fire risk, hence a series choke.

Even if one has beam antennas on a tower or mast the best solution is undoubtedly a good external earth system, and it is worthwhile from an operating point of view if any unbalanced antennas are used. As I mentioned low radiation resistance is important and makes the antenna pattern of directional aerials much more predictable, which can only be a good thing. TVI is also likely to be less likely. Burying a length of copper wire, pipe or tape the length of the lawn may be more rewarding than expected, and is likely to be much more effective than the normal earth electrode. It will also reduce the danger from lightning, by controlling the potential surrounding the antenna system. I have no difficulty bonding this to the MET, perhaps with a high current RF choke, in TNC-S installations, again serious mains voltages are much less likely than RF ones, which can cause both shocks and severe burns to the unwary. The household should be aware of this danger.


I have a good copy of Dud Charmans Aerial Circus DVD available which you may like to borrow as there is a lot of good antenna (and earthing for RF) material discussed. PM me if interested. The one on youtube is obviously ex 6 generations of VHS and useless! I made this many years ago for Dud, with the Bristol TV group, so as good as we could manage at the time, the youtube one is an unauthorised rip-off, I hold the copyright.


Regards

David CEng MIET G8FNR.

I have to take significant difference with Clive Brittain on this one, simply because he does not appear to understand the difficulties with TT should there be other extraneous parts (such as central heating pipes or radiators, storage heaters etc.) in the shack. It is simple to TT an outbuilding but not part of an internal installation in a house. I think the worry about lost neutrals is excessive, there are many more serious significant dangers with high power radio equipment, and often much higher potentials available, as well as seriously dangerous RF potentials. The word shack does not mean shed, it is a technical term for the radio operating space! It is possible to TT the whole building installation, but this is not always wise where there are buried metal services which are extraneous to the building, or everything around the site is a TNC-S installation which must always be assumed. RCD protection in line with BS7671 2018, is suggested whatever the installation type. Unfortunately advice from average electricians about this kind of installation is very unlikely to be satisfactory, most struggle with normal TT installations in my experience. Items and the external earthing system may be separately bonded to an Earth marshaling terminal if desired in the shack, and thence to the MET. RF voltages on the house electrical system are very undesirable, and could be a fire risk, hence a series choke.

Even if one has beam antennas on a tower or mast the best solution is undoubtedly a good external earth system, and it is worthwhile from an operating point of view if any unbalanced antennas are used. As I mentioned low radiation resistance is important and makes the antenna pattern of directional aerials much more predictable, which can only be a good thing. TVI is also likely to be less likely. Burying a length of copper wire, pipe or tape the length of the lawn may be more rewarding than expected, and is likely to be much more effective than the normal earth electrode. It will also reduce the danger from lightning, by controlling the potential surrounding the antenna system. I have no difficulty bonding this to the MET, perhaps with a high current RF choke, in TNC-S installations, again serious mains voltages are much less likely than RF ones, which can cause both shocks and severe burns to the unwary. The household should be aware of this danger.


I have a good copy of Dud Charmans Aerial Circus DVD available which you may like to borrow as there is a lot of good antenna (and earthing for RF) material discussed. PM me if interested. The one on youtube is obviously ex 6 generations of VHS and useless! I made this many years ago for Dud, with the Bristol TV group, so as good as we could manage at the time, the youtube one is an unauthorised rip-off, I hold the copyright.


Regards

David CEng MIET G8FNR.