Re: Antennas: Best Mini-Whip ??


jdow
 

Are you sure the rod went IN rather than bent and mushroomed away from the layer of shale? Rocks are definitely something that defeats ground rods. At that point you get a pro to drill the hole. Once through the shale dribble water and go down to the next layer if any. And then realize that the nice ground you think you built is not all that spiffy. Ground conductivity is usually not all that good with shale or granite, particularly on mountain tops.

I think I'd play with EZNEC or one of the other antenna modeling programs that will model real grounds. Then play with the antenna design over shale and tune the system to get better results. EZNEC is addictive. And do remember you're not likely modeling the whole environment such as buildings, cars, fences, and other lumps of conductor in the area. You get approximate results that need real life tuning.

{^_-}

On 20210918 21:00:39, Gedas wrote:

Your intentions are good, and appreciated, but w/o knowing the type of ground someone has your advice may or may not be of much help. I will share a story about my quest to drive in about a dozen 10' long ground rods each 5/8" dia steel, heavy copper coated into very nasty hard ground.

EVERY method I tried resulted in total failure & frustration. This back when I was healthy and thought nothing of swinging a 10 pound sledge hammer all day. My ground here in NE Indiana is some form of horrible nasty good for nothing clay/shale mix. You can get a rod pounded in about 2' with great effort and then all you will do is mushroom the top of the rod and end up with a sore back with an 8' rod sticking out of the ground that cannot be removed. My 2 acre pond holds water very well.

Tried every trick I had ever heard of w/o success. Tried beating the crap out of it with every hammer I owned, no luck. Tried the heavy steel pipe with massive metal cap and handles, same results. Tried a 3/4" conduit pipe sharpened at the tip and a garden hose attached at the top with a hose clamp (and water turned on full flow) and repeated thrusts up & down hoping to make a water drill, zero luck and a huge mess. Tried to fill the started holes with water and let them sit for several days to loosen up the crap below.....the water level NEVER went down.

What I did end up using that worked like a gift from heaven was renting an electric jack-hammer that weighed about 80 pounds and stood 3-4 feet tall. You remove the huge 10 pound steel bit that normally goes into the hammer and you are left with a nice 1.5" dia hole maybe 8" deep that fits very nicely over the top of the ground rod. I sat up a step ladder next to the rod, lifted the jack-hammer up over the ground rod and let it rip. The ground rod drops in length like magic just from the weight of the hammer slamming away. Total time per rod is about 5 minutes. If you have normal soil those other techniques may work but if you have this crap we have here called ground then the jack-hammer is the only way to go.

Gedas, W8BYA EN70JT

Gallery at http://w8bya.com (under repair)
Light travels faster than sound....
This is why some people appear bright until you hear them speak.
On 9/18/2021 11:23 PM, jdow wrote:
Dribble a hose where you want the ground rod to go in overnight with a very slow dribble so the ground absorbs it well. Then push the silly thing in with your hand unless you have very rocky soil. In that case the ground rod is never going to go in nicely.

The approved tool is a 2' section of galvanized pipe with a cap on it. That will drive it in straight with modest effort. At least that's what I am told. I used the dribble technique and the rod went in like a warm knife into warm butter. It didn't quite sink on its own. I live in a former flood plain for very serious storms. (As in 1969 shortly after I moved into Ca we had Cosby weather. "Let it rain for 40 days and 40 nights until the sewers back up." We desperately need that sort or weather again.)

{^_^}

On 20210918 10:37:13, Curt Faulk wrote:
At this juncture I should point out that I did not ground my installation by conscious choice. I actually have an 8-ft ground rod and was prepared to get everything properly grounded, but I just never got around to picking up the hammer drill to drive the thing into the ground. It's a good thing too, because I'm about to move all of my equipment to my other QTH we're grounding should be much easier to accomplish.

My plan is to properly ground and bond the station.


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