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Cords, Columns and More Ground Rods

Keeping things clean is the bane of the broadcast engineer.

Keeping things clean is the bane of the broadcast engineer.

George Sperry, general manager of WEVA(AM-FM), Emporia, Va., was doing some preventive maintenance recently, and was washing the station building windows using one of those Windex-brand spray units that screw onto a garden hose.

After completing the windows, and with an ample amount of spray left, George turned the nozzle onto the fiberglass dish in the side yard. It cleaned the grime and bird droppings from the dish, without the need for a ladder. In about 15 minutes, both 3.5-meter dishes were clean, and looking new.

Now for a spray-on wax, to simplify removal of snow and ice when the winter months arrive! Thanks, George, for the tip, and for sharing routine maintenance tips with engineers, even though you are a GM!

. . .

Not far from Emporia is the home of Thomas Jefferson, Charlottesville, Va. There, the Eure Communications group has kept the Jeffersonian style of architecture in its studios by designing columns that double as wire-running raceways.

(click thumbnail)Fig. 1: This wiring column in Charlottesville, Va., has a Jeffersonian feel.
Figure 1 shows one of two columns placed at the edges of the studio furniture, used to route all wiring into and out of the studio. The columns are a novel way to get the job done, and in the tradition of Thomas J.

. . .

We don’t always have the luxury of locating studio furniture so that electrical access is hidden.

Brian Edwards of New World Radio solved the problem of plugs accidentally being removed by securing the cables as shown in Figures 2 and 3.

The service “loop” permits the plug to be removed, when the need is presented. Otherwise, a leg brushing along the cords won’t dislodge them.

. . .

John Stortz’s ground rod project has generated more response than any other Workbench topic. I appreciate everyone taking the time to pass on your suggestions.

Few of us have the benefit of working next to a sage engineer anymore, learning all of the tricks of the trade. That’s what makes this column so special. We can all learn from one another. Keep up the great exchange of ideas, readers.

(click thumbnail)Fig. 2: Keep power cords secure with this simple precaution.
John sent a follow-up message regarding the connecting of ground rods. It seems you can buy ground rods with the “hammer end” threaded. Two ground rods can be screwed together using a threaded coupling.

Someone recommended that John use threadless couplings, which cost about a dollar more than the threaded ones. The saving is that you don’t have to buy threaded ground rods, which is a substantial. The threadless couplings are tapered to fit by friction. The harder you drive the rods, the tighter they become joined.

It’s been John’s experience that the threaded couplings tend to unscrew as they are driven into the ground. This problem is eliminated using the threadless couplings.

Mike McCarthy has driven over a hundred ground rods over this past year. After hammering away with the sledgehammer, like John Stortz, Mike had a “pounder” made for him. It’s like a pile driver, but weighs more than 50 pounds. It’s good for one or two rods in light soil.

As his jobs increased, though, Mike started investing in the heavy-duty tools. Makita makes a ground rod-driving cup for its 1-1/8 demo hammers. Mike paid about $80 for his. He also invested in bits from Bosch and Dewalt, for spline and SDS Max drivers. The type used depends on the soil and the depth. Many of these tools can be found at industrial rental companies.

Mike invested in a Bosch SDS Max hammer driver for moderate soil. The tool was well worth the money, because it easily bores holes for transmission line passage in block walls.

(click thumbnail)Fig. 3: Keep power cords secure with this simple precaution.
If the soil is really hard, Mike will rent a 60-pound demo hammer and use the heavy bit from Makita. He’s only had three cases where he could not drive a 3/4-inch rod the full depth.

When faced with really hard soil, the best tool combination is a two-cycle gas demo/driver from Kawasaki, again using the Makita heavy bit. Mike drove a 15-foot rod into hard clay soil in about 10 minutes. It took the heaviest electric model an hour on another rod.

Ed Dulaney at KLZE/Crawford Broadcasting in Colorado offers a simpler approach. In soft soil, Ed has used a t-post fence post driver. These are hollow steel tubes, closed on one end, open on the other. The handles welded to the closed end forms the “T.”

These drivers can be used for drive the rod to a depth of 14 to 20 inches, before resorting to a sledgehammer to complete the job.

In sandy or light-density soils, a standard half-inch chuck hammer drill will work. Although this tool takes longer, it’s less exhausting than slamming the rod with the T-post driver or sledgehammer.

I’ve saved the simplest suggestions for last. Leave it to the hams to have the lowest-cost solution. Ken Romero from KXKC(FM) in New Iberia, La., was taught this trick by some ham operators. It’s a good solution for only a few ground rods.

First, take a garden hose and soak the area where the rod will go. Take the rod, and like a spear, stab it into the ground as hard as you can. Place the garden hose next to the rod, and while running water into the hole, rock the rod back and forth about a foot or so, while applying downward pressure. A sledgehammer might be needed for the last couple of feet.

Brian Urban is a lab manager at the Department of Engineering Technology at the University of North Texas. Brian’s trick is similar to that described above, and is courtesy of the power company.

Brian watched while the power company workers stabbed the rod into the ground, filling the hole with a small amount of water before repeating the stabbing action. When installed in soil with a low clay content, a standard drinking cup full of water was enough to drive an 8-foot rod in only a couple of minutes.

The last foot or so must be hammered, but a lot of effort is saved letting the water do the work.

Submissions for this column are encouraged, and qualify for SBE recertification credit. Fax your submission to (703) 323-8044, or send e-mail to[email protected].