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Earthing and the radio amateur

Stewart Mason
I've recently joined the IET forums. I replied to a  topic regarding amateur radio and PME on the old forum. Unfortunately I cant access the old forum anymore so I thought it would be best to start a new topic.


So. On the bench there is a transceiver with a metal case. Next to the transceiver there is a antenna tuning unit which is connected to a antenna system which is using an earth rod. Am I right in saying there is a chance of a potential difference between the two metal cases of the equipment regardless if it is a TT, TNS or TNCS?


What would be the ideal solution?  Put the shack on it's own TT supply and bond all the radio equipment back to the MET of the TT and if a earth rod is used for the antennas connect that back to the MET also?


If the TT system was not an option what would be best if the supply was a PME and you didn't want to use balanced antennas removing the use of an earth rod? 


To be honest I've never really given PME's and amateur radio much thought which in hindsight was probably a mistake. I do remember when I did my training an earth rod was recommended for the radios.


Apologies for being so random.


Stewart M0SDM
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  • 0
    I might be able to help you here John. I have a smallish garden which is also my wife's pride and joy, so she won't give me planning permission for towers, beams or guy ropes Frowning2.


    I have put up an end fed half wave HF antenna. It is 20.1 metres long and runs from the house to a pole attached to a pergola, then across to the roof of our summer house (i.e. L shaped). The wire is 1.6mm hard drawn copper, and I sprayed the pole olive drab to blend in with the trees. The antenna height is approximately 4 metres and it is very hard to see.


    Now for the interesting bit. It is fed from the house end via a 49:1 unun. From there a metre of RG58 coax connects to a line choke then a further 7 metres runs to the shack, which is upstairs. The 1 metre length acts as a counterpoise for the antenna. The coax shield on the "cold" side of the line choke is connected to a ground rod to drain static electricity. The ground rod is also bonded via a line choke to the property's main earth terminal.


    I measured the antenna's VSWR with an analyser and the results on 40, 20, 15 and 10 metres are below. I use an LDG automatic tuner to improve it further and 100 watts SSB. There is no RF earth in the shack due to its height above ground, and absolutely no RFI. The first time I tried it the TV picture died, but that was due to poor filtering on the DAB radio input of my distribution amplifier in the loft. A 50MHz HPF fixed that.


    The results are impressive. I have had a 5/9 report from 1200 miles away in Bulgaria.


    Mike G8GYW


    2a71a008c423b121fee00491c7167ac4-huge-antenna.png

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  • 0
    I might be able to help you here John. I have a smallish garden which is also my wife's pride and joy, so she won't give me planning permission for towers, beams or guy ropes Frowning2.


    I have put up an end fed half wave HF antenna. It is 20.1 metres long and runs from the house to a pole attached to a pergola, then across to the roof of our summer house (i.e. L shaped). The wire is 1.6mm hard drawn copper, and I sprayed the pole olive drab to blend in with the trees. The antenna height is approximately 4 metres and it is very hard to see.


    Now for the interesting bit. It is fed from the house end via a 49:1 unun. From there a metre of RG58 coax connects to a line choke then a further 7 metres runs to the shack, which is upstairs. The 1 metre length acts as a counterpoise for the antenna. The coax shield on the "cold" side of the line choke is connected to a ground rod to drain static electricity. The ground rod is also bonded via a line choke to the property's main earth terminal.


    I measured the antenna's VSWR with an analyser and the results on 40, 20, 15 and 10 metres are below. I use an LDG automatic tuner to improve it further and 100 watts SSB. There is no RF earth in the shack due to its height above ground, and absolutely no RFI. The first time I tried it the TV picture died, but that was due to poor filtering on the DAB radio input of my distribution amplifier in the loft. A 50MHz HPF fixed that.


    The results are impressive. I have had a 5/9 report from 1200 miles away in Bulgaria.


    Mike G8GYW


    2a71a008c423b121fee00491c7167ac4-huge-antenna.png

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