Thanks both for your concern and suggestions.
the earthing basics pdf. looks useful and i will certainly study that before moving any further.
Just to be clear while I appreciate this is a high voltage it is extremely low current (as soon as I noticed this I tested the current and was immeasurable with the Fuke Multimeter on mA range) and dissipates to nothing when measured after a few seconds of even high resistance (My hand).
While I never claim to be an expert in these matters hence me asking, I am reasonably practical and experienced in basic electronics (manufacturing and fault finding) and understand the basics of electrical installations. Worked as a integrated security systems engineer for most of my life. Not radio I know but from the old analogue video days and even today with RS485 and 422 data networks know a little about the problems of earth loops. For video especially they were a nightmare on large sites with differing earth potentials.
Anyway I digress
All that said this one is still puzzling me so but let me tell you what i have found so far and see what you think.
Firstly I have no antenna earths at all at the moment which is why i am starting to look at this and ask some questions. Initially to reduce some noise. I only noticed this high voltage when I started to look into it further. I think what I am seeing or feeling is some sort of floating earth on my Antennas. I am sure my house mains earth is ok but never rule anything out so will check that. I only feel or measure this between antennas and or antennas and metal chassis of the radios when all disconnected. When everything is connected I feel nothing and can measure no voltages between radios, antennas or mains earth.
My Antennas are all in my loft,
I have a long wire and a home made active whip type thing from years ago for my Shortwave. Neither of these are earthed in anyway.
For my scanning my main antenna is a dual band 2m - 70 cm Fiberglas type, Diamond X30 I think and an old Mobile wide band Scanner antenna that I have clamped to a central heating pipe (possible problem 1st there).
The worst one I get is between the Dual Band and radio chassis when disconnected. When disconnected from the radio it is completely isolated and not touching any metal in the house at all (bolted on a bracket to the loft joists)
This is the same as i get between the dual band and mobile scanner antenna that is bolted to a pipe. This Pipe is connected to mains earth as you would expect with house earth bonding? I think this is my first mistake guess.
Next is my radios. I have no issues between radios when measured but I think I do have a less than ideal arraignment. For power 2 radios and the active antenna are on one 12v PSU and one of the other is on its own 15v PSU and the last is mains powered. none of the chassis earths are connected to anything or each other. What I have measured is that 1 and only 1 the chassis is connected to the PSU negative. maybe because its designed as a mobile set?
I did initially think I had a PSU issue as I was measuring a small voltage between the psu case and the negative output (arround 2-3VAC) but think this is a red herring as it changed depending on antenna connections so for the moment i am ruling that out.
Sorry this is a lot of info and I am probably not really getting the the details across very well but what I am thinking at the moment and would value you input on is that I feel I need to earth everything consistently. Certainly all the radio Chassis. Not sure what to do about the Dual Band antenna though. Should it have its own or will connecting it to an earthed radio be enough?
I am also guessing this should be completely independent of mains earth and I need to conform none of the radios chassis are connected to mains earth currently. Or should they be connected to Mains earth as with normal household appliances?
Lastly get that mobile antenna off the central heating pipes!
Am I heading in the correct direction here or is my thinking completely wrong?
Many thanks for baring with me on this and advice is genuinely appreciated.
By the way my current system works ok. Not massively noisy or def but know it could be better. sadly I am stuck with it all being in the loft rather than outside which will limit things
Thanks
Ian