I have been working on the grounding system at my house. There have been many satellite dish system put in my house over the years and all have used a rebar ground rod of unknown length to ground them. Not my doing but someone through it was exceptable. The rebar ground rod is locate just out side the window where my ham setup is located. Today I drove 2 new 5/8" copper clad 8' ground rods 10 feet apart for my radio grounding needs. My home has a a ground rod by the service entrance but it is 65 feet away. Tomorrow I will add a 6ga bare copper wire from the new rods installed today to my existing services ground to bond them together. Thats about the best I can do but I may add another ground in the mix also. My soil is all sand here in Michigan. Now I need a Surge Protect or lighting arrester to start bringing my coax and ground wire into the house. I have looked at HRO and DXE but there seems to be so many different ones. Does anyone have any recommendations as to a good one to use. I am using RG8X coax to the radio.
Grounding/Surge Suppressor
- Thread starter billdean
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prcguy
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Good for you following NEC and grounding your new rods to the house main AC panel ground. Except rods are usually placed at least twice the distance apart as they are long. Any lightning arrestor or coax ground block in the coax run near the house entry point connected to your new or original ground rods with 10ga or larger copper wire should meet NEC. Some arrestors will do better with a nearby lightning hit where HV is induced into your coax center conductor and that is snuffed out at a reasonable level before it can damage a radio or tuner, etc. Polyphaser has some that work ok and there are some with replaceable gas discharge cartridges that work ok.
But that won't protect you from a direct lightning hit and frankly nothing will unless you have the knowledge or hire a company to completely design and retrofit your entire house and AC entry with a new ground system specifically for surviving a direct hit. That is possible and I've worked at many mountain top repeater sites where antennas have been blown apart from a direct hit and they have had countless hits on the towers over the years and everything inside the building is fine. That would be very expensive to have designed and installed.
I was a licensed Journeyman electrician many years ago. I have been retired now for almost 15 years. The NEC has changed many times sense I was practicing. At least 3 if not 4 book revisions. Anyway I will look into the polyphase and others if someone has some other recommendations too. I have seen the replaceable gas dischargeI ones. I guess any will work until you have a real lighting strike close by. Then you will know.
prcguy
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From my research, if your antenna gets a direct hit its not like you have a hundred million volts between the coax center conductor and shield, bringing a hundred million volts into your radio circuit board and that can be tamed with a coax lightning arrestor. Its more like a common mode thing where the center conductor and shield are basically going to be around the same hundred million volt potential but there could still be a big difference between what's on the shield compared to the center conductor and enough to damage a radio.
More than likely the difference in potential between the antenna ground and house AC entry point ground will be a bunch of ohms different and that will blow up nearly everything plugged into an AC socket in the house with a direct hit due to a couple million amps wanting to equalize between the different ground potentials through your ham radio and TV and stereo and whatever. So without that complete redesign and rebuild of your house and antenna grounding and lightning bypass upgrade your radio and most electronics in your house are all toast with a direct hit.
In a nearby strike that simply induces lots of voltage onto your antenna from a distance like a long wire HF type, there can be thousands of volts between the coax shield and center conductor and a good lightning arrestor can tame that but the arrestors can have a clamping voltage that is higher than what some radios might handle. For example there are some arrestors that will clamp at around 90 volts for use with very low power transmitters and for receivers. For a full legal limit level the arrestor will have to pass up to 300 volts in a 50 ohm system before clamping and probably more like 600 volts to cover a reasonable deviation in impedance from 50 ohms. Using that higher power arrestor can allow enough induced voltage from a nearby strike to wreak your 100w transceiver or receiver or even your 100w auto tuner but your full legal limit amplifier might survive since its designed to handle 300V or so at the antenna connector whenever you use it.
K6GBW
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My house an a ground system called a UFER ground. Basically the ground for the house is encased in the concrete footing. They work but as time goes on they rust and become problematic. When I put in a new circuit breaker panel I had them install three ground grounds. They had to run a ground cable through my attic to make it all work due to concrete in the backyard. They also bonded all the pipes and the gas lines. A put in a fourth ground rod and bonded it to the house system just for grounding coaxes coming into the house. I've used Polyphasers for the last several years. Two years ago we had an electrical storm and a lightning strike hit on the street behind me. Guess what? That strike put enough juice in the air to blow one of the Polyphasers!
As PRCGuy said, a direct strike is so powerful there's not much you can do. But keeping the lighting outside the house might prevent a fire. I also have a static bleeder on my wire antenna due to the dry winds we get here.
Nothing you do will be perfect, but do the best you can. Still a good idea to unhook coaxes during a storm though...belt and suspenders and all that.
As PRCGuy said, a direct strike is so powerful there's not much you can do. But keeping the lighting outside the house might prevent a fire. I also have a static bleeder on my wire antenna due to the dry winds we get here.
Nothing you do will be perfect, but do the best you can. Still a good idea to unhook coaxes during a storm though...belt and suspenders and all that.
I am getting my system ready for next spring when I return from southern Arizona/California. When I return to Michigan in the spring the ground is sometimes still frozen. I will be leaving here about the 15th of October for the Yuma area. I will have a different set of problems down there. Mainly the wind. My plan is to mount an unun for and end fed antenna to 10 or 20' pole and run the wire parallel to my 5th wheel to keep it out of the way. I have a 33' end feed that may work out ok. I believe I will have 10 though 40 meters which is good. I don't think a ground rod will be in my plan down there. It should be OK to put the pole in the ground a few inches and strap it off to the ladder. There is lighting down there but I haven't seen it to much of it. Probably more static the anything. New experience with a ham radio in my 5er. Anyway I am purchasing one of those Polyphasers for here in Michigan.
