Appraisal of Setup esp. Grounding!
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| Apr 28th 2020, 06:48 | |
G5UKTotal Topics: 0 Total Posts: 0 |
I wondered if a few of you very knowledgeable folks wouldn't mind to appraise my Shack/Antenna setup especially with regards to Grounding/Earthing? Also would love to hear any general suggestions for improvements. I have tried hard to follow best practices and read up a lot, but doubtless I'm missing a few things. All the information is on this diagram: http://tiny.cc/u01xnz Looking forward to the opportunity to further improve and optimise. Thanks & 73! Ben G5UK |
| Apr 28th 2020, 07:41 | |
W1VTSuper Moderator Total Topics: 0 Total Posts: 0 |
Ground outdoor masts (and metal structures that support antennas) in accordance with 810.21 [810.15]. Obviously the UK doesn't have to follow NEC rules of the USA, but I thought it may be helpful to add that in the USA, metal structures that support antennas should be grounded. You may want a direct path to ground between the VHF vertical mounted on the house and ground. Zak W1VT |
| Apr 28th 2020, 10:48 | |
G5UKTotal Topics: 0 Total Posts: 0 |
Thanks Zak. The separate grounding of the mast, metalwork and roof antenna is a great point and should be shown here. Does anyone see any issue with our advantage to the two earth rods for RF ground in the diagram http://tiny.cc/u01xnz - one being by the shack and the other near the the antennas? |
| Apr 28th 2020, 13:19 | |
W1VTSuper Moderator Total Topics: 0 Total Posts: 0 |
I don't see any advantage to having two separate earth rods over a distance of 45m. You need the one near the shack as a single point ground. Ideally, you would build a Faraday cage around the shack but a single point ground is a reasonable compromise. Zak W1VT ARRL Senior Lab Engineer |
| Jun 1st 2020, 19:12 | |
gw0nvnTotal Topics: 0 Total Posts: 0 |
Hi A quick one. Just had a look on your QRZ page. Have a look through the OFCOM technical documents. They have specifications for grounding of masts and transmitter buildings. ( sorry can't find my copy ) There are the IEE Wiring Regs. Grounding and Bonding for the Radio Amateur ( ArrL ) is useful. The Article " The Killing Fields " by the RSGB explains PME ( Protective Multiple Earthing ) and how not to mix it with RF earthing. Polyphaser have some good documentation. Confederation of Aerial Industries has information Other observations I would not use RG213 for your long antenna run. Due to the high losses and dilectric breakdown especially under high VSWR. eg 28MHz 696 W assuming no mis-matches with 1KW in from your Accom 700S. Looking at the photo of your surge arrester. Your coax connections are not well made or weather proofed. Dampness will ingress into your cables and will ruin them very quickly. Poor connections will introduce mismatches and galvanic noise issues. Check the RF Connectors that you use. Best quality with ptfe dielectric. I've had ( PL259 ) arc with static caused by wind through a dipole. One glowed purple in a car in a lightning storm. I thought it was a cigarette lighter!! Try to make a surge arrester for your Ladder line before it is connected to your outside ATU. The GB2 Marconi Station on the Lizard had an article in PW discribing what they did. Basically a spack gap on each leg to a ground spike. It is worth thinking about the other services coming into your shack. Phone line/internet, data cables, audio feeds. Proper earthing and filtering will minimise noise issues. Also the new OFCOM rf safety audits we now have to do. Same as in the USA. If you are going to be on VHF and UHF using ssb FT8 etc, I would suggest that you also install some Horizontal polarised antennas for those bands. Even omni-directional ones. As I have measured losses of over 20 dB ( 100x ) when measuring field strengths, when using the wrong polarity. I'm renewing my feeder cables. My pipes were full of snails! Best regards 73's Simon GW0NVN N1XIH |
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