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Author Topic: Ground rods, how?  (Read 14497 times)

White Tiger

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Ground rods, how?
« Reply #15 on: October 17, 2012, 11:58:09 PM »
Ok, great - and thanks!
If you're looking for me, you're probably looking in the wrong place.

gil

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Re: Ground rods, how?
« Reply #16 on: October 18, 2012, 12:06:58 AM »
The fence post pounder was $28 at Home Depot. I figured I'd use it again... You're welcome to borrow it if you come down here for work...

Gil.

White Tiger

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Ground rods, how?
« Reply #17 on: October 18, 2012, 08:43:55 AM »
Thanks Gil, might take you up on that! Did you get the ground rod at Home Depot, too?
If you're looking for me, you're probably looking in the wrong place.

gil

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Re: Ground rods, how?
« Reply #18 on: October 18, 2012, 10:54:16 AM »
Yes. They're not all copper, but copper clad steel rods... It was cheap, don't remember exactly..

Gil.

White Tiger

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Ground rods, how?
« Reply #19 on: October 18, 2012, 11:15:39 AM »
Hmm...copper-clad, steel rods, driven into soil with a high water content...



Sounds like you have a battery!

At the very least it seems like it would generate electrolysis - you may have to swap out that bar in about 18 months - I don't think it will still be 8' long by then! I have some customers that make Aluminum Seawalls - they call that a "Sacrificial Cathode" it draws current away from the Seawall - which allows the current to consume the cathode...first..
« Last Edit: October 18, 2012, 11:17:54 AM by White Tiger »
If you're looking for me, you're probably looking in the wrong place.

gil

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Re: Ground rods, how?
« Reply #20 on: October 18, 2012, 11:21:21 AM »
Yep, I used to have a 32ft steel boat. I had zinc blocks along the hull. They went first before the steel...

Gil.

RadioRay

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Re: Ground rods, how?
« Reply #21 on: October 18, 2012, 12:00:48 PM »
Grounding -v- grounding ...

The ground rod is good for electrical safety as in the refference to the National Electrical Code & etc.  I have also found it VERY useful in eliminating stray RF inthe shack when the antenna and feedline combination was not correct for a particular frequency, causing RF burns and computer resets: all gone when the station had a god ground.  Remember though that this is not the same as a ground for transmitting - at least not in most soils with average conductivity.  A ground rod in soil - despite what the old Army manuals say -  'looks' like a shortened antenna in a leaky resistive environment when it comes to radio frequency energy.

However, If you operate with a balanced antenna like a diple or one of the half wave wires with short counterpoise, this grounding of the station does not cause any problem at all and you get the benefits of the grounded station frame, in removing stray RF energy. If however, you're running a wire int he air against a ground rod, you would be far better using a counterpoise wire and/or radials for your 'ground return path'.

I know that this sounds odd, but remember the RF electronics theory & practice is very different from DC and even low frquency AC as used in house current. So, at RF, not all grounds are equal or for the same purpose.


You're Welcome for the confusion.... ha ha


de RadioRay ..._ ._
"When we cannot do the good we would, we must be ready to do the good we can."  ~ Matthew Henry

Mitch

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Re: Ground rods, how?
« Reply #22 on: October 18, 2012, 02:07:41 PM »
Could I slightly change the topic?

Maybe to something like "Ground Rods, When?"

My current policy is for any system I setup- if it doesn't plug into a house/campsite/power company receptacle I don't ground (earth ground) it. I also don't play radio when there is even a remote chance of lightning. All of my antennas are portable and temporary!

I'm interested to know everyone's opinion since I've gotten conflicting reports on the correctness of my policy. Several times I've been led to believe I need at least a temporary ground rod- but other than basic lightning protection I don't see the point (see last paragraph).

When I used a tuner with my radio I had a short wire to ground the radio case to the tuner backplane (chassis ground) but it never made any performance difference and I didn't really think it served much safety purpose for my FT817ND and Z-817 tuner which is also battery powered...

My needs for RF grounding are served by dipoles, radials, or feedline. I'm not really asking on opinions for RF grounding- I think I have a handle on that!

Signed: "Lost and Confused"

KC9TNH

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Re: Ground rods, how?
« Reply #23 on: October 18, 2012, 08:58:27 PM »
If however, you're running a wire int he air against a ground rod, you would be far better using a counterpoise wire and/or radials for your 'ground return path'.

Every field-expedient wire I've used including those since licensed and playing with little end-fed toss-in-the-tree solutions has always worked better with a counterpoise; never got best results going directly to a rod. (Talking about the antenna here, not some need to ground the radio.)  If the feedpoint is going to be up there too for awhile, a radial (counterpoise of the air, so to speak) comes back down away from the feedpoint. Put it to an insulator and tie off the rest with paracord.

Interesting thread. Caught my eye & triggered a memory. We used to have equipment in one shelter & then tailgate it with a "maintenance" rig (which really held some spares and our special chow stash & the coffee pot). Came out of the 'kitchen' & stepped over to the tailgate of the equipment rig and got belted right back into the kitchen. (Spilled my coffee too.) Apprentice generator kid had daisy-chained all the rig grounds in our little area. He got no candy bars, pound cake or peaches.

They should charge more for the exam and just have everyone walk away with an ARRL antenna manual just for a few core sections of that book.

 :)

Genken

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Re: Ground rods, how?
« Reply #24 on: November 05, 2012, 12:46:39 AM »
Uh...wha?

Ok, so I guess I'm doing it wrong then. My current in-the-works project is my Diamond HV7A on a ~9' mast. Now, what I've done is gotten a 20' feedline to go into the antenna on top of the mast, and run a ground line to a ground rod(or other grounding point). This is a mobile antenna, and my understanding is that when it's mounted to my car, the grounding to the vehicle can make or break my ability to transmit efficiently. So I assume put in a mast, it would be the same?

Or would I be better off trying to come up with some ground radials?

The problem I'm seeing is being a mobile 70cm, 2m, 6m, and 2x HF antenna (Only have the 10m loading coil on, but also have the 20m and 40m in my trunk), it could get real confusing on how long to make the radials?

Either way, I should have pictures of current setup when I get back home in the next few days, partly as a tutorial, partly to get some insight on what I could be doing wrong. Have not had the chance to try it, trying to spend time with family before I deploy soon, but will try to get it up and give it a test run before too long.

Jim Boswell

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Re: Ground rods, how?
« Reply #25 on: November 13, 2012, 11:16:53 AM »
Some good points here. If you live someplace where people drill water wells, you can find out how deep the sub surface soil moisture is. If you don't want to use salt to decrease soil conductivity you can use copper sulfate, but it costs more money.
Someday when I put my tower up I plan to use one vertical and one angled ground rod for each tower leg. Keep all ground connections in good cond. either solder them, cad-weld them or use pentatrox to stop corrosion.
73'S  KA5SIW

Sunflower

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Re: Ground rods, how?
« Reply #26 on: November 18, 2012, 11:57:48 PM »
Thanks, now I need to find someone who can loan me a steel fence post pounder!
Or maybe they're cheap enough...

Gil.

We have one - or two. My husband build his. They look simple enough. Sorry I don't have a pic. Glad I have another use for the fence post helper.

Sunflower

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Re: Ground rods, how?
« Reply #27 on: November 19, 2012, 12:03:38 AM »
I need to get that ARRL Handbook. I am not clearly visualizing the variations here. (leaving 6 inches out of the ground, using 6, diagonial).

With most of the antennea being mentioned above, are these enough for CW.?

gil

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Re: Ground rods, how?
« Reply #28 on: November 19, 2012, 01:18:15 AM »
Hello Tess.

A ground rod has nothing to do with the mode you use, and is not the antenna or any part of it. Well, not really. It is just a six foot steel rod covered with copper that you pound into the ground and connect to a lightning arrestor, which is like a double female coax plug with a ground lug. If lightning strikes the antenna, the current is redirected to the ground rod instead of your equipment. That's the theory anyway. I don't know how well they work. It also provides somewhat of an RF ground and can help the antenna to radiate properly. Also, it can prevent RF to go back to your shack. I did not have to install one, but lightning is very common here, and my end-fed dipole is just a few feet from my bedroom window, so.. I never leave my radio plugged-in when not in use, but you never know, I might forget sometimes..

Gil.

Here's the type of arrestor I used:

Ken

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Re: Ground rods, how?
« Reply #29 on: May 27, 2013, 10:27:15 PM »
Here is excellent resource: http://www.protectiongroup.com/ProtectionTechnologyGroup/media/PTG/WhitePapersandTechnicalNotes/1485-013.pdf

Epson salt is preferred electrolyte but MUST be continuously renewed.  In severe cases an Epson salt drip is used to maintain conductivity.  Also note that multiple rods should be separated by no more than twice their length.

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Re: Ground rods, how?
« Reply #29 on: May 27, 2013, 10:27:15 PM »