horizontal ground rods ???

[BOOTY MONSTER]

anyone ever tried this ?

Ground Rods in Rocky Areas

Ground Rods in Rocky Areas
May 11th Fact-of-the-Day
It is practically impossible to drive a ground rod in some mountainous areas of the western United States and in certain other parts of the world without rock drilling equipment or dynamite. In some areas it is not just a matter of breaking or pushing a few rocks to the side as a ground rod is driven, because there is a thick, solid layer of rock below a thin layer of top soil. Even if a rod was driven by some means, the result would be a 'rock rod' rather than a 'ground rod.' A better alternative is to bury a similar (or preferably longer) length of copper pipe horizontally below the top soil. A ground rod can be buried horizontally instead, but a ground rod costs more than copper pipe, the mechanical strength of a ground rod isn't needed, and the wall thickness of copper pipe is greater than the thickness of copper plating on a ground rod. ©2005 Martek International All rights reserved.


???

 

[Wire Weasel]

I doubt the effectiveness of any grounding device only buried at shallow depth. There will be insufficient contact with the 'earth" to do any good.

 

[The Jerk]

I did a pretty intense geotech drilling project around some large radio towers...they did not have ground rods, they had ground "radials" which were nothing more than large gauge wire buried only a foot or so under the ground.

I know this because the guy operating the towers was a fanatic and was completely paranoid we might hit one (even though the towers were being demo'd). He had the radials all marked out and was happy once we got past two feet below ground surface. Now these were quite long (each tower had probably ten or more wires that extended radially over 500 feet, and supposedly these also had smaller wires hooking these together (think spider web).

I know I have read where guys bury 5 x 10 foot panels of the wire reinforcing mesh for concrete as a ground.

Edit: these towers were probably 500 feet tall or better...there were at least two big ones, and a smaller one IIRC. Its a strip mall today...

 

[W5LZ]

What you are talking about is a ground radial instead of a ground rod, and they work just dandy. In fact, they work better than ground rods. Grounding doesn't depend on how deep the conductor is, that's a misconception, deep ain't better. That's true for RF grounds and safety grounds. How deep should a radial be? At least under the grass, so that they don't get caught in a lawn mower, or you don't trip over them. Deeper won't hurt, but real deep doesn't help either.
Why don't people use radials instead of ground rods? Because the rods are easier to do than laying in radials. Usually don't take near as much effort and time.
- 'Doc

 

[Wire Weasel]

I did a pretty intense geotech drilling project around some large radio towers...they did not have ground rods, they had ground "radials" which were nothing more than large gauge wire buried only a foot or so under the ground.

I know this because the guy operating the towers was a fanatic and was completely paranoid we might hit one (even though the towers were being demo'd). He had the radials all marked out and was happy once we got past two feet below ground surface. Now these were quite long (each tower had probably ten or more wires that extended radially over 500 feet, and supposedly these also had smaller wires hooking these together (think spider web).

I know I have read where guys bury 5 x 10 foot panels of the wire reinforcing mesh for concrete as a ground.

Edit: these towers were probably 500 feet tall or better...there were at least two big ones, and a smaller one IIRC. Its a strip mall today...

Yeah, that needs a little more clarification. On an AM Broadcast tower, the tower itself IS the antenna. It's a ground-mounted 1/4 wave Ground Plane. The tower is the radiator and the in-ground horizontal radial system is the Ground Plane (other electrical half of the antenna - both together mathematically creating a half wave dipole).

So these are Ground Plane Radials and not a DC grounding system as the OP is discussing.

 

[vo1ks]

If you're hoping to protect electronic equipment inside the building, you need to ensure proper bonding between the tower and AC grounds. The two grounds will often operate at different potentials, particularly during an electrical storm. Without a proper bond, any currents between the two will flow through the equipment. Proper site layout and construction will allow the building to 'float' at whatever ground potential there is and suffer no damage.
I have links in this document to several RF site preparation and grounding documents that are very good.
http://members.rennlist.org/warren/grounding.pdf

 

[BOOTY MONSTER]

i didn't get the impression the article was saying the horizontal rods were optimal or even as good as a typical vertical install in dirt ... but that it's "A better alternative" for a earth grounding method than trying to ground in thick or mostly rock earth .

what would be a better earth grounding alternative in thick rock or very rocky soil than the method suggested in the article ? i won't have this problem , but was wondering just for future reference .

 

[Wire Weasel]

i didn't get the impression the article was saying the horizontal rods were optimal or even as good as a typical vertical install in dirt ... but that it's "A better alternative" for a earth grounding method than trying to ground in thick or mostly rock earth .

what would be a better earth grounding alternative in thick rock or very rocky soil than the method suggested in the article ? i won't have this problem , but was wondering just for future reference .

Probably no good ground is even obtainable in that circumstance. "Radio Shack" Grounding to begin with is an option, not a necessity.

And there is always the MFJ Artificial Ground unit. MFJ-931

 

[W5LZ]

The MFJ-931 is NOT for safety grounding at all, only RF grounding. Using it for a safety ground is asking for trouble and it will usually get it's 'wish'. It's also a tuned circuit that is frequency dependent. Meaning that when you change frequency you will need to re-tune that MFJ-931. I have no idea what it's normal 'range' is before that re-tuning is required, but it's there.
Safety grounding is not simple and what works in one circumstance may not be adequate for another situation or site. Wouldn't it be nice if it was??
- 'Doc

 

[Wire Weasel]

The best safety ground, short of doing tons of hard work and spending hundreds or thousands of dollars, is to disconnect your antenna and power leads from everything in the shack and isolate them, during a thunderstorm period.

 

[vo1ks]

Installed properly there is no need to disconnect the antenna during a storm. The feedline enters the house so the energy will be inside anyhow. With the RF side of things properly designed, installed, and bonded you could talk all the time during a lightning storm and there should be no damage. Cell towers, broadcast AM FM and TV stations, paging and other communications systems don't shut down during lightning storms...

 

[freezy]

At last something I know about...

All kinds of cool Grounding Electrodes in 250.50- In the National Electric Code.

A horizontal "ground ring" must be at least 20ft long, 2GA and in direct contact with the earth.

You can ground to a chunk of rebar encased in concrete at least 2" thick in direct contact with earth. The rebar must at least have 20 feet of galvanized or bare exposure to the concrete

 

[The Jerk]

So these are Ground Plane Radials and not a DC grounding system as the OP is discussing.

No, they were lightning protection...as frequently pointed out by the operator. Maybe they served two purposes, but I was told multiple times they were for lightning protection.

 

[IRock817]

The local news showed some pics of a large tree that had been stuck! The tree was in splinters!
I have all my equipment bonded to a ground rod installed six inches from the base of my push up pole. The push up pole and the mounting plate of the antenna are bonded here as well.
When we have storms in the area I disconnect my feed line and the ground cable coming into the shack. Seems like these cables would be a direct path to all my equipment! I damn sure don't talk during a storm.
I had the opportunity to see the lightning arrester at one of our local radio stations! These broadcast stations have more protection then I would have imagined.

 

[Wire Weasel]

Installed properly there is no need to disconnect the antenna during a storm. The feedline enters the house so the energy will be inside anyhow. With the RF side of things properly designed, installed, and bonded you could talk all the time during a lightning storm and there should be no damage. Cell towers, broadcast AM FM and TV stations, paging and other communications systems don't shut down during lightning storms...

Of course, but they have done TONS OF HARD WORK AND SPENT THOUSANDS OF DOLLARS ON CORRECT GROUNDING SYSTEMS. The typical private hobbyist can't do that.