The objective of this trial is to cover the entire yard from front to back at 1550kHz, an uphill stretch all the way. Transmitting downhill from an vertical antenna always works but getting uphill to the rear has never happened.
The idea is to run a single buried ground wire from the building up to the top of the hill on the theory that doing so will usher the signal up all the way.
By sundown tonight the wire was laid to the half-way mark, and after it had been dark awhile, I walked out there with a portable and the signal was solid right to the half-way mark where the wire ended. Previously, before the ground wire was installed, the signal would have been dead by that point, so the indication is that my idea is working. Interestingly, the signal does not go at all beyond the end of the ground wire, put is strong along its sides.
Tomorrow the rest of the test.
Coupling
” Interestingly, the signal does not go at all beyond the end of the ground wire, put is strong along its sides.”
My inital take is that it works along the sides because of proximity coupling with your receiever antenna, so of course it quits at the end.
I wish we had a better picture of your property. E.g., how high is the hill and what is the grade? Does it go above your roof? Is the grade at an angle to form a reflector section to where you could build an opposing side above ground? What relationship does it have to your broadcast studio? How far away and in what direction? Measurements?
I’ve formed a few imaginary images of what could be done based on your posts, but each time I seem to get a different idea of your property which changes things and my ideas go out the window.
A Verbal Map
Thank you Ken N. for your interest in studying the situation here at KDX.
1.) The lot. About 70′ wide and about 300′ long. The longer length rises uphill at a guess of 20 – 25-degrees constant uphill grade, with north at the bottom.
2.) The building. Small brick house located center of lot, 1/2 way between top and bottom of hill.
3.) Transmitter. SSTran located indoors at rear wall, with 10′ vertical connected through the wall, actual antenna against back of building. Even though this antenna faces toward uphill direction, it actually does better around front on the downhill slope.
4.) Ground. A heavy gauge copper wire (insulated) leaves the building at dirt level and follows the earth 1/2 of the way south up the hill in back, I still have not finished extending it all the way to the top. The signal is good all the way along side the ground wire.
5.) Extra ground. The transmitter is also grounded to the buildings I-beam, which helps even out the indoor reception all through the house.
6.) Future. In addition to extending the rear ground wire all the way to the top of the hill, I will extend an additional underground wire in front from the I-beam in the house north down to the bottom of the hill, to help fill in any signal weakness down there.
7.) Intention. The only intention is to solidly cover the lot with no interest in reaching the neighborhood, so I probably won’t put side radials to the east or west.
Thinking outside the brick
The lot refs probably help. It’s an interesting puzzle, since AM travels on ground wave during the day.
I keep thinking about how my signal dies pretty much at the edges of town, but yet can sometimes can be picked up miles away in certain locations and conditions, often with what I’d consider unhelpful terrain between. Hard to come up with hard data to work from, let alone figure out why. I need to do some more driving, reading and figuring.
Years ago when I was flying SAR’s with the CAP Lake Tahoe Sqdn,, we were doing an electronic search, and encountered the ELT signal West of Reno just below Verdi Peak. They had already done a ramp check at Reno, but couldn’t find it.
In the end, they did another airport search on the ground and found a slightly open hangar door. The signal was coming from an aircraft parked inside. The signal was escaping under the door and was bouncing off mineral deposits on Mt. Verdi.
The whole thing drove us crazy for a day …
We Take Advice
You’re telling us, Ken N., that we’re bouncing off mineral deposits. I wondered if that was happening.
Suggestion
Carl,
I hope you’re not burying those ground wires. Laying them on top of the soil and pinned down under the surface of the grass will actually work better than buried 3-4 inches under the surface. The only reason the FCC requires that AM station ground radials be buried is to protect them from being damaged or stolen. In an enclosed area (residential yard) that would be less of a problem.
Another point to consider, mass and area coverage is more important than one extra long ground radial conductor. Fanning out 3 or 4 ground radials in a particular direction “pinned to the soil surface would be more effective than one big long “herkin'” ground radial. In your stated installation, the ground radial is the main radiating antenna element. And because it is longer than the transmitter antenna, the ground system becomes the primary radiator. The ground has become the antenna and the antenna has become, in a sense, the counterpoise. And as such, ground conductivity becomes a major factor in the performance of your station’s signal. When it rains the range is increased, when it dries out, the range decreases.
Just thought you ought to have other input on your test. Good Luck.
Buried in Part
Right where the ground wire leaves the building it passes about ten feet over a walking patio made of 10X12X1.5 concrete blocks, kind of like a”computer floor,” which can be lifted and replaced. I just spent all afternoon putting that section under the concrete blocks, but in wilderness areas it will pass through ground-cover-ivy on its way to the end.
It does not, so far, appear to be radiating, because the strongest S-meter readings on the radio are near the vertical antenna, but the weaker signal does seem to be true all along the ground wire.
It still does not go all the way up, but that will happen soon.
When this leg of the job is finished I will look at the idea of adding the multiple branches as suggested. But once the lot is fully blanketed, that will be the completion, because this is not a public radio station.
Monster On Maple Street
“You’re telling us, Ken N., that we’re bouncing off mineral deposits. I wondered if that was happening.”
No, not necessarily, especially at such low power … it was just a comment on strange things happening with RF signals.
Remember the one where I got a signal for about 15′ on a dirt driveway 4.5 mi. from town? It disappeared on either end of that 15′ stretch, didn’t pick it up again until I was nearly inside the town limits. Someone suggested buried power lines … which there is one there that used to power a lamp for a small sign down on the main road (the driveway goes Duck Soup Inn, a famous restaurant about half way to Roche Harbor). But why only that one section?
BTW, according to my research, I certainly agree there should be multiple radials, even if they aren’t all the same length. There is a little wheeled device I used to use on a tree farm to bury vinyl irrigation lines, very shallow. All you need is to get the wires so they won’t get caught in your mower blades.
Brain Radiation
Since all the radiation my brain is really slowing down, but I just realized that the advice to avoid burying the ground wire, while being good advice for performance improvement, would violate the 3-meter ground lead-in rule, therefore, to be legal, the wire must be buried.
Losing is required.
Winning is not allowed.
therefore, to be legal, the
therefore, to be legal, the wire must be buried.
That’s not true, is it?
Back to This Again
Some discussions never end, such as what is the difference between a ground lead and actual ground. Since my wire is on the ground, maybe it is the ground. Here is where someone usually says that it depends on what the inspector says.
Radials are OK so far
“would violate the 3-meter ground lead-in rule, therefore, to be legal, the wire must be buried”
??? Chapter and verse please …
AFAIK, ground radials are not considered ground lead nor transmission line. I haven’t seen any citations issued for ground radials. Right enough, eh? …. I also would say go ahead. Save worrying for if the signal starts getting picked up across the state 😉
If your brain is radiating too much RF, I suggest having it disassembled and studied by impartial scientists 😉
Messing with the Status Quo
Ah, Ken N., it’s the brain again, making me question the status quo. Of course I know what is meant by an “impartial” scientist, but I wonder if that is the same as a bored scientist or an indifferent one.
Judges these days are not often impartial but more bent toward the punitive, especially when generating revenue for their employer.
Living an impartial lifestyle might be like being neutral, the way the Swiss are, but the marriage won’t last.
Oh, goodness, you mean this is being shown on the internet? Please be impartial. It’s the Amplitude Modulation.
Total Success and Belief
Opening this thread was my declaration of finally putting down an outside ground wire with the hope of improving reception at the top of the hill in the back yard. The problem was my AM signals were not climbing the hill and were almost un-listenable up there.
Good news. It worked. The signal up there is now very usable and the one wire in the ground did the job.
The signal outreach in the neighborhood has not changed much, maybe just slightly. But that wasn’t the objective.
To double check the work I disconnected the ground, re-tuned, and the signal up on the high ground was gone. There is no doubt about the improvement.
Thank you for so much input.
To Carl…
Carl. You are only experimenting right now.
I wouldn’t worry about the ground lead issue.
Just my opinion. Also, when you get the ground
project done, try to retune your transmitter and
coil for max signal and see what you get.
If your transmission still doesn’t go anywhere,
who cares. If it does go somewhere, then we
can talk about the ground lead issue(?). At least
that’s the way I see it.
Right now we are all learning from this.
Best wishes,
Bruce, MICRO1690/1700
Gradual Changes
Before adding a long ground wire from the building up to the top of the hill in the rear yard, grounding was achieved through jumpers S1 through S3 in the SStran3000, which couple to audio ground and power line ground. With that method there was a strong signal in the house, outdoors in front on the downhill side, and 1-block in all street directions;
Adding a copper ground from transmitter up to the top of the hill in back, perhaps 150-feet, and unjumpering S2,3 (power ground), the signal shifted and became strong all along the path of the ground wire, but became weak toward the front downhill and no longer reached up the street very far. Audio ground (j1) was kept jumpered to avoid a motor-boating sound.
Finally, both ground methods have been combined, and tomorrow the measurements will be made, but it’s definitely better out front.