Ground Rod VS Radials

Following real-world experience I am taking the position that only ground radials are capable of pushing a part 15 AM station's range to its maximum legal outreach.

So many of us have tended to believe that a ground rod can accomplish something of the same thing but I find otherwise.

Think of it as a 3-choice process...

A part 15 transmitter with only a 3-meter vertical antenna and no serious ground will not provide impressive reach. The relationship between antenna and ground is at best a very high impedance affair with little useful result.

A part 15 transmitter attached to a ground rod will tune-up beautifully on the output meter because the impedance between transmitter and ground is sufficiently reduced to provide a ground path to complete the circuit... except, that the highly resonant well tuned signal will be confined to an area near the ground rod and will not extend to the far field. In fact a ground rod is merely a negative dipole element buried in the ground where it loses potency.

Only ground radials will serve the radiated signal out to the distance by "claiming" the ground-plane and coupling it with the antenna system.

The final frontier amounts to trying different numbers of and lengths of radials.


jimhenry2000's picture

Your property sound a lot like mine, thin coat of top soil over granite. Where i located my antenna was on one side of my back lot where the builder had to blast. it's still very rocky there but with patience I can get something in the ground. My property is currently covered with 80-120 foot Pin Oaks.

As to getting a wire over a tree branch, Ham Radio outlets sell devices to do that, or you could just use a bow and arrow with a string tied to the arrow. Once you get the string over the branch tie your wire to the end of the string and pull it over the branch.

Jim Henry HBR Radio 1610, serving Honey Brook, PA. and NW Chester County.

MrBruce's picture

jimhenry2000 Said:

As to getting a wire over a tree branch, Ham Radio outlets sell devices to do that, or you could just use a bow and arrow with a string tied to the arrow. Once you get the string over the branch tie your wire to the end of the string and pull it over the branch.

MrBruce Said:

Good gravy! I would hate to find out I hit someone with that arrow.

Police: "Why did you kill the victim?"

Me: "I was trying to errect an antenna and they got in the way sir."

I tried that and had miscalculated the throw with a fishing pole and line with a lead weight on the end and just like when you are fishing and snag a tree, the line wrapped around a branch way up there and stayed there, I couldn't get it to come undone for the life of me.

That lead weight is still dangling up there swaying in the breeze.

If it was possible, I'd post pictures of my back yard, I have plenty that I took to show station8 as his living in Florida, I wanted to give him a clue as to what I am up against living in Norwich, Connecticut. Very hilly terrain and lots of ledge rock. In fact, they had to blast like crazy, just to build this building into a hillside. Front of the building has a lower landscape as compared to the back, which is higher, with the lower apartments having their backsides buried in the ground. The building is two stories, four apartments. Mine is on the second floor, the front is two stories, but on the backside, the ground level is equal with the level of my apartment. When I dug up a portion of the yard to create a garden, the aboundance of rocks is unbelieveable!! In fact, we built walls and sidewalks out of those rocks because there was so many of them, we had to do something with them.

However, some rocks are impossible to move, tried that already, without blasting, those aren't going anywhere unfortunately. The wooded lot area isn't that wide east to west before it comes to a wall dividing the property next door, perhaps it is around 12 feet, then on the other hand, the same lot running north to south is a lot wider, running perhaps 1000 feet or more. But there are a lot of trees and growth, dead leaves, old dead tree branches in that lot that are obsticles that need to be cleared.

Burying an antenna base could pose a problem, if ledge rock is below the surface, obviously, without drilling, or removal of those large rocks, planting an antenna base in the ground for stabilty could be impossible to do, then of course the ground radials in some cases can't be buried in the ground, because the ledge rock is sticking up well above the surface in some cases, including the roots of that one lone tree I mentioned earier, because of the ledge rook, that tree can't bury its root system deep enough, so in areas, those roots stick up out of the ground as well.

On top of all that, I still have to figure out how to create a decent tuning coil arrangement.

I've been doing a lot of reading on coils. I am still confused on the number of wraps for the proposed frequency of 1620KHz.

What to do with the unused portion of the coil below the bottom tap.

I have bookmarked many forum topics regarding the coil.

If I followed the directions as they are published, by creating a tap every turn or every two (2) turns around a cylinder, I have to figure out where to tap the coil for the driven element and where to tap the coil for the source, the transmitter.

Now, the remaining question is, "What do I do with the coil area below the bottom most tap?"

Do I cut that wire and remove it from the coil?

Also, how many feet of wire total is needed to begin with for 1620 KHz?

If the two taps use a total of only 10 feet of the coiled wire and the coil has a total length of 100 feet wrapped around the cylinder, what do I do with the other 90 feet of wire below the lower most tap? Leave it in? or cut and remove it?

How many feet should I start with in the first place? What cylinder circumference should be used for best results?

Wire gauge and how many strands? Solid or multi strand?

LOL many questions in this post huh?

As an extra obsticle, Chris Cuff has never giving an exact answer as to the Ohms or impedance of his C-Quam AM stereo kit's out put. The schematic for it is confusing because it shows two areas where the antenna can be hooked up, depending on whether you add the high power section or not, which isn't high power at all, lucky if it does a nano watt on high power, but since the schmatic shows the antenna output in two locations, it is difficult to determin the actual impedance output. He basically has two coupling caps in series if you use the high power mod, but I wonder if one of the caps should be removed if the high power kit is added. (SEE THE LETTER (E) IN THE SCHEMATIC DIAGRAM WHERE THE 0.047 CAP AND THE 150Pf CAP ARE MARKED AS "RF POWER AMP STAGE" TO SEE WHAT I AM REFERING TO) Should those two caps remain is series if the RF POWER AMP STAGE is added?

Here is the schematic for the final stage:

Here is a link to the actual schematic diagram:

Am I confused? Sure the hell am folks!

Perhaps, I should stop here, before I load down the crew with too many questions, huh?


jimhenry2000's picture

Mr. Bruce,

I'm assuming that the arrow point would be replaced with something blunt and soft (clay?) to provide enough weight for the sake of balance.  Anyway here are some other options:

Jim Henry HBR Radio 1610, serving Honey Brook, PA. and NW Chester County.

kc2wex's picture

Why is it not possiable to use a coil buried in the ground to extend the reach of a ground radial. (buried means put in a box for weather sake)? I understand a ground stake is inappropiate just to mention it but the radial itself is like an antenna radial along with the antenna, except it is buried in the ground for signal bouncing purposes. if possiable, it were loaded, you can extend the ground radial`s reach. Just a thought.

radio8z's picture

The induced electric field is radial around the antenna so the the currents returning to the antenna are also radial.  Conductors axial to the antenna would not see an electric field nor the currents resulting therefrom.