John, Hubbell & Nvent-Erico both make threaded ground rods. I think both need a threaded coupling for both. Chemical grounds work but are seldom used around here, they become less effective over time, and need care to install as most use a sodium based chemical the corrosion factor is high, also no grass will grow around the rod for years. The practice here and in most locals is to use multiple rods 6-10ft apart. That is the practice at most all cell phone sites. Motorola published a grounding guide for communications sites, deals with best practices in grounding and lightning protection. Do not recall the publication # but it is online It is Standards and Guidelines for Communication Sites. Due note the book is 500+ pages long. Not easy reading, but a good guide. Your sandy soil is great for pushing in ground rods by hand, that type of soil is what N5XZ had at his tower site & we pushed in 4 or 5 at his tower base. Sandy soil is fairly conductive when damp but less so as it dries out (keep the water hose handy) Robert
From: BVARC <[email protected]> On Behalf Of john Parmalee via BVARC Sent: Wednesday, May 25, 2022 9:14 AM To: [email protected] Cc: john Parmalee <[email protected]> Subject: Re: [BVARC] grounding Robert, thanks for your comments. I will check Elliott for screw together g rods the next time I am in town. I live in far southwest Montgomery county, We don't have gumbo here but sandy loam. When I put my last g rod in I used a section of PVC connected to a garden hose to wash six or so feet into the ground then a sledge, One thing that has not been mentioned is chemical grounds. I recall trying to make a 35 mHz paging system work. One thing we did was to install chemical grounds on all the towers involved. That didn't work, the frequency sees a modern office building a as a wave guide below cut off and just doesn't penetrate, I have read stories about trying to get a good ground while building across the desert power transmission lines. John Parmalee [email protected] <mailto:[email protected]> 281-380-3811 K5VGM WI2XLJ In a message dated 5/25/2022 7:13:24 AM Central Standard Time, [email protected] <mailto:[email protected]> writes: Robert, At my installation the only one I am really concerned about is the ground for the DSL into my house (NOT installed by myself) that is a pipe, not a rod. I clamped a ground wire to a sanded portion of the pipe, and bonded it to my station ground, but I think the pipe thing is a real bad idea. Given that it is an AT&T thing, do you have any suggestions other than what I have done? Ron Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for Windows From: Robert Polinski via BVARC <mailto:[email protected]> Sent: Tuesday, May 24, 2022 8:29 PM To: john Parmalee <mailto:[email protected]> ; BRAZOS VALLEY AMATEUR RADIO CLUB <mailto:[email protected]> Cc: Robert Polinski <mailto:[email protected]> Subject: Re: [BVARC] grounding John, they do make thread together rods, when I did commercial communications I have used them at comm sites. Here, a 10ft ground rod is fine as are wet gumbo soil makes a pretty good ground. The NEC requires 2 ground rods or a ground rod and a ufer ground, which can be rebar in the slab, metal water line or metal bldg. if in contact with the earth via rebar or poles. I usually install 2 rods. Most 10 ft ground are easy to push in the ground with just your hands. I just a few weeks ago installed additional rods at a hams house in the Heights. I wired a home in Elgin, just outside of Austin. Had to install horizonal ground rods as the ground was solid rock 2 ft down. I always tie to an existing rod but always add an additional rod as you never know if the old ground rod is 10ft or 18” Here in the Houston area, testing is not necessary because of the soil, but as the video shows, it is a neat test. You are correct in your bends in the grounding conductor, they will act as a choke if made sharp, also, you should no run the ground wire in metal conduit for the same reason unless you bond the ground wire to the conduit at both ends. As far a lightning goes, remember, all the wiring the strike travels thru on the way to the earth has resistance & inductance, so by the time it gets in the circuit the voltage & current are greatly reduced, still high, but since the duration is short, a good grounding system will dissipate quickly. Robert From: BVARC <[email protected] <mailto:[email protected]> > On Behalf Of john Parmalee via BVARC Sent: Tuesday, May 24, 2022 6:31 PM To: [email protected] <mailto:[email protected]> Cc: john Parmalee <[email protected] <mailto:[email protected]> > Subject: Re: [BVARC] grounding >From what the great video says, if you are comfortable working with 120V the >simplest way to check out a ground rod is to see how much current it will draw >and do the math. Don't attempt this without experience working with a live >circuit. I have been told by licensed electricians that when a new service is >turned up if there is the stub of a ground rod sticking out of the ground it >is good. No testing required. The thing I don't know is where to get the ground rod to ground rod connections and the ground rods with the blunt ends so they can match the previously driven rod. Lowes only carries the 8 or it 10-foot rods and the coupling to the flex wire to the service box. I checked Amazon and found nothing. I am told the local rental yard will rent a hammer drill and the ground rod driving adapter. Another comment regarding the ability of a ground to carry a lightning strike. All bends of the ground wire should have the gentlest bends possible. A strike of lightning is a very fast rise time having many harmonics. We know this because we can hear lightning almost to the VHF bands, A bend will look like an inductor and raise the instant ohmic value of a ground rod. On the other hand, a few turns on a coax or power source lead will increase the ohms to you rig.it will not protect against a direct hit but might fend off some induced current from a nearby strike. In south Florida it is common to tie several knots in your modem phone line. In Michigan they wrap a phone line around a ¼” bolt , some washers and a nut.. John Parmalee [email protected] <mailto:[email protected]> 281-380-3811 K5VGM WI2XLJ In a message dated 5/23/2022 7:54:42 PM Central Standard Time, [email protected] <mailto:[email protected]> writes: If any one is interested in ground rod resistance, you can watch the link below. One thing I want watchers to note, they have 2 50ft ground rods connected together, they hook the hot side of a 120v ckt to them and it only pulls 13 amps (not enough to trip a breaker), that is why the grounding system must have a bond back to the power co ground always. Note this is not related to the RF grounds used as a counterpoise to an antenna system other than they will be tied together at a point. Robert https://www.youtube.com/watch?v=Yg6G5VUSsWA ________________________________________________ Brazos Valley Amateur Radio Club BVARC mailing list [email protected] <mailto:[email protected]> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org Publicly available archives are available here: https://www.mail-archive.com/[email protected]/ <https://www.mail-archive.com/[email protected]/> ________________________________________________ Brazos Valley Amateur Radio Club BVARC mailing list [email protected] <mailto:[email protected]> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org Publicly available archives are available here: https://www.mail-archive.com/[email protected]/ <https://www.mail-archive.com/[email protected]/>
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