Pme earthing

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MrPaul009
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Pme earthing

Post by MrPaul009 » 04 Jun 2018, 16:09

Hi all can I connect a ground wire to the back of my receiver to a ground rod close to my shack with pme electrical system?many thanks

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Transwarp
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Re: Pme earthing

Post by Transwarp » 04 Jun 2018, 17:01

Ooo err, need to be extremely careful nowadays with RF grounding (earthing) of shack and antennas as depending on it can actually be reportable work under part p electrical regs. It's all got more involved with the different types of electrical earthing so I'd speak to a savvy qualified electrician, or if there's one on here then they may have better advice. You don't want your equipment (or whole house) taking over as the earth point for your whole road / street!
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Re: Pme earthing

Post by MrPaul009 » 04 Jun 2018, 17:42

Hi there,the reason I was asking was I get a bad ac noise on low frequency's but when I connect the ground wire on the back of my receiver and then the the earth rod the noise goes.

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Re: Pme earthing

Post by Transwarp » 04 Jun 2018, 17:54

Understood, however as said need to be careful about, hence why a good experienced electrician will know more about. When I had an operational shack I had a couple of ground spikes for my equipment and antennas, however I admit I'd not looked into how my house was supplied electrically from the distribution network so potentially I could have been asking for trouble, still don't know now but I'm not set up anymore so doesn't matter.

Regarding the AC noise that you say goes when connecting to a rod, I'm not sure if that would be electrical noise being picked up or a fault? I found that grounding is good for static (hash) but no noticeable benefit for other types of picked up noise. Somebody with a lot more experience than me will contribute in a bit for you no doubt.
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Re: Pme earthing

Post by Sam P » 04 Jun 2018, 18:13

Exporting or importing an additional earth from a PME property can be very dodgy. Under fault conditions (with a fault in the supply earth away from the house) you can potentially generate dangerous voltages at the earth of your shack.

Seek professional advice or leave well alone would be my advice.
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Transwarp
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Re: Pme earthing

Post by Transwarp » 04 Jun 2018, 18:42

MrPaul009 wrote:
04 Jun 2018, 16:09
Hi all can I connect a ground wire to the back of my receiver to a ground rod close to my shack with pme electrical system?many thanks
Links below about earthing.

http://rsgb.org/main/files/2012/11/EMC0 ... -Basic.pdf

http://rsgb.org/main/files/2012/11/UK-E ... v1.3a-.pdf
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MrPaul009
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Re: Pme earthing

Post by MrPaul009 » 04 Jun 2018, 19:57

Thanks guys,I better take it off then.

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Re: Pme earthing

Post by paulears » 04 Jun 2018, 20:04

Nowadays, there's a popular misconception that you shouldn't extend the equipotential zone of the property by adding an extension to an outbuilding - but the modern ground path of modern installs is so good, why wouldn't you extend it 17th regs (not up to date ion the 18th) never made this extension wrong. Some people separate the shed ground with a plastic incoming ground on the SWA, and then use an RCD in the shed for fault condition safety - but realistically, if your installation is TN-C-S then your bonding conductor would need to be at least 10mm where your radio grounds bond with the house bonding point. So if the noise is cured by the ground rod, just makes sure the bond to the house earth can withstand the fault current if something horrible happens in the house.

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Re: Pme earthing

Post by MrPaul009 » 04 Jun 2018, 22:13

Hi there,I don't really no what you mean,sorry for being dumb.my house electrical system is a pme system, but I get a horrible noise on low frequency(bottom part of mw)but if I connect my ground to my radio the noise disappears.how can I cure the problem with no earth to my receiver?many thanks.

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Re: Pme earthing

Post by Tigersaw » 04 Jun 2018, 22:26

I see no harm in it so long as the radio is isolated from the house electrical system -
ie run on batteries, or make sure the psu has no link between the earth connection in the plug and the -ve supply conector (or +ve for that unlikely matter).

I had a switch mode that the chassis and -ve connector were at earth potential, and I have a linear psu I use now that is fully isolated at the output.
Check and see

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Re: Pme earthing

Post by Transwarp » 05 Jun 2018, 16:20

MrPaul009 wrote:
04 Jun 2018, 22:13
Hi there,I don't really no what you mean,sorry for being dumb.my house electrical system is a pme system, but I get a horrible noise on low frequency(bottom part of mw)but if I connect my ground to my radio the noise disappears.how can I cure the problem with no earth to my receiver?many thanks.
The first thing I always did if I was having a problem with interference was run my sets off a 12v battery as a process of elimination, if it's possible for you to do same as a check then I would do that first and in doing so if you've no more hum or anything then you know you have 'noisy' AC in your home which you might have success in curing with filtering rather than earth grounding. This is assuming there isn't a fault with the set itself of course.
Last edited by Transwarp on 05 Jun 2018, 17:02, edited 1 time in total.
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MrPaul009
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Re: Pme earthing

Post by MrPaul009 » 05 Jun 2018, 16:30

Hi there, I have made a new matching transformer for my flag antenna.20 turns high impedance/5 turns low impedance. And it's cured the problem.many thanks to you all for your help.

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Re: Pme earthing

Post by Transwarp » 05 Jun 2018, 17:03

MrPaul009 wrote:
05 Jun 2018, 16:30
Hi there, I have made a new matching transformer for my flag antenna.20 turns high impedance/5 turns low impedance. And it's cured the problem.many thanks to you all for your help.
Result then :thumbup:
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Re: Pme earthing

Post by paulears » 05 Jun 2018, 18:34

It's a kind of urban myth that you cannot connect the earthing of the house to the earthing of the outbuilding. Mains systems all have tremendous scope for causing hums and voltages getting where they shouldn't. If your shed is only connected to the house live and neutral (no connection to the wire sheathing in the SWA cable) and you belt in an earth stake into soft and moist earth at the shack end, and run out an extension cable from the house. It's quite possible you will have the neutral in the shack above 0 volts with respect to the local earth, and even testing between the extension lead earth and neutral might not give exactly 0. The question is how much is acceptable. Under normal circumstances not much current will flow - but these circulating currents can play havoc with common equipment. Computers connected to amplified devices often go mad and him like the devil and video gear has hum bars up and down the screen and it messes up transmitter audio too - plus off course, the harmonics can be pretty powerful. If the joining of the grounds reduces interference and noise, it's usually safe to do.

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Re: Pme earthing

Post by Transwarp » 05 Jun 2018, 18:39

paulears wrote:
05 Jun 2018, 18:34
It's a kind of urban myth that you cannot connect the earthing of the house to the earthing of the outbuilding.
You a qualified sparks? :think:
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