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We have talked about this in the past, how sometimes our little AM transmitters induce a carrier onto the power lines even though some of us use a radiator and are not intentionally coupling a signal to the power lines via , well a coupling unit.
Since moving to 1620 AM , our coverage has doubled a bit. The weather has been horrible lately, mostly just windy , rainy and just plain miserable to do any kind of work in the yard, that includes the outdoor antenna for AM 1620.
Despite the crummy weather, i have had a chance to listen on the car radio while making our way to town for some grocery shopping and I have been pleasantly surprised by a very nice clear signal for nearly a 1/4 mile from the house, maybe even further than that!
I really don’t understand how this can be working so well considering the following conditions involved, you see as long as the listener is in their car or house they have a really good chance to hear Blue Bucket Radio on 1620 AM. Especially if the listeners radio is close to the power lines or better yet, the radio is plugged into an AC outlet. The key is they have to be within view of the power lines which follow the main road that branches off of my short no outlet road.
The conditions in the house, the SStran AMT3000 is using the short wire antenna provided in the kit, the transmitter sits on my desk, the antenna runs up the wall for 2 feet before making an inverted L across the ceiling. The ground (black wire) is not connected to earth ground, it just hangs off the back of the desk.
The only grounding i can think the transmitter is using would be the connection made through the power adapter and the audio chain.In fact the outlet i am using gets it’s power from the house wiring that runs the length of the house to the bathroom which is towards the back of the house at probably 80 feet total length from the studio to the breaker panel in the bathroom. Weird Huh?
Included is a map of the area my signal can potentially cover and if you download the map and enlarge it, you can see where the house’s and roads are but it’s not that easy to see the power lines. Some of the power lines weave in and out , near the road in some places and then back behind a few houses before going back out to the road and eventually meeting up with 4 huge transformers, from there the power lines go North and disappear into the hills.
I doubt the signal passes through the transformers considering those things put a loud buzz in any radio close to them.
I really hope this isn’t some kind of a fluke and continues to reach out there beyond our road, for a good idea what i am rambling on about, view the attached map, download it too for a bigger view. If you download the map, you can zoom in to get a better idea how things are laid out here.
I think 1620 is going to work out just fine for Blue Bucket Radio.
WOW I did not use spacing or even create separate paragraphs…geez.
Total posts : 45366My wire antenna for the talking house am transmitter is a few inches from a breaker box. If you figure out how you did this and made it into a carrier current type of fact I’d like to try to do the same thing here.
Total posts : 45366Graet image there in the mountains that really helps to visualize the range.
I’ve noticed the same carrier current effect almost since I first got my Talking House and started to do tests and got several times the range along the lines as compared to going off road, and had peaking at the poles on a portable radio.
One pole at the main intersection had a high power signal in it, strong as a local broadcaster, at .25 miles away from my house, on 1610. The signal is also insidious, in other metal items like guardrails and fencing around my road. It made me laugh knowing my signal was in all that metal in the area, sly and devious 😉
To give you an idea, the over the air signal is maybe 150 feet from my house away from any power line, and it’s fading out. At the far end of the carrier current range, going away from that pole with the strong signal even 10 feet away, it’s weak again.
I tried it different ways, didn’t realize it was carrier current until I lucked on it with part of the Talking House’s wire antenna in parallel with a length of unclad house wiring at least 6 inches away.
I tried other things, like laying the antenna next to the TH’s own power cord, but that was much worse, almost no carrier current or range. Keeping the antenna far away from the power cord was a lot better, and almost always produced a good carrier current effect.
Wrappng the antenna around the same power line that was producing the carrier current so well, doing a spiral wrap didn’t allow the the transmitter to tune properly, I think it went to ERR on the displya, and wouldn’t transmit.
It seems like a new discovery, because the info that’s out there says it won’t work and don’t bother trying, either with 100 milliwatts, it’s too low to go anywhere, or that the high band won’t work.
The Low Power Broadcasting company’s literature even talks about the low band being the best, and goes on to explain why that’s so. Maybe all that about the power and frequency is true on a school campus in the city, but it’s worth a try in single family residences.
A couple of things I want to try: Tuning to a lower frequency and testing the range, and making a tuner for the 50 ohm output port on the Talking House to couple and tune it directly to the power line.
Thanks for going back and using paragraph spacings too, sometimes when someone writes it keeps flowing. I often skip long posts that are solid text, though I’d have read yours since it’s something I’ve had experience with and learned the same thing!
Total posts : 45366Well, providing I don’t happen to run across a true Carrier Current system at the Belton hamfest (long shot) this weekend, I will experiment with “Unexpected Carrier Current” when I get back.
I have a TH 5.0 that works, but where I am trying to use it, we have awful powerline noise. It drowns out almost all AM stations when you get near it. When you move out beyond it, I can hear my TH that I have run in a test mode while I decide a direction for my project.
I can see that conceivably, coupling from the transmitter wire of the TH to the power line would occur. I am not afraid to try a direct connection with a neutral / ground combination at my location. I have been sticking my fingers in AC since I was a kid working on my first tube radio. And before I scare anyone, I would fuse/protect etc etc. properly. Do as I say, not as I do…
I like the map, that is pretty impressive coverage for an Unexpected Coupling and low power. Does make you wonder what 5 or 10 watts would do!
Anyone else doing this now or going to experiment with this??
Breaking up the text definately helps. My brain generally thrives on unexpected coupling and low power. Paragraphs are our friend!
Total posts : 45366An effective coupling link from a transmitter RF output into a powerline will also work in reverse… all the radio frequency noise and energy in the power line will enter straight into the transmitter’s output stage, creating a severe condition known as “standing wave” which can possible blow the output stage of the transmitter.
The true couplers made for carrier current have a main function of de-tuning, which is to say minimizing, the standing wave so that most of the transmitter’s RF energy goes OUT to the powerline and as little as possible reflected power comes back into the transmitter.
Total posts : 45366I have several amateur radio tuners that conceivably may be able to tune into the neutral line, but the power out of the TH won’t trigger the meters. However, I also have an antenna analyser that will let me set the tuner and any other coupling/safety devices that may be needed to connect.
It is my opinion, that even if successful with the experimentation of a TH direct connection with various cobbled together couplers, one’s best interest would be best represented to finalize the products into an organised installation with necessary safety measures compliant with local code. In other words, lets not leave a bunch of wires hanging out of the breaker box and/or power outlets.
BTW, I just scored a new book for my library…”An Introduction to Carrier Current Communications” by J.N. Petrie Should prove to be interesting, if not outdated!
Total posts : 45366I have thought about trying carrier current, but first, I’d have to purchase an AM transmitter. My Chris Cuff C-Quam AM stereo transmitter does not have any reasonable output stage to cover 20 feet or more, so I will probably have to look into purchasing another type of AM stereo transmitter with better output stage.
What concerns me is the fact that I have a utility pole mounted downstep transformer right where my home’s mains connects to the utility company’s 1000 volt supply line. Would this isolate me from the utilty mains running down the road and make using carrier current useless for me to try? Incidently, I am on a dead end road off of a secondary road.
Bruce.
Total posts : 45366If you neutral load it the signal should be able to pass the transformer. If not there is a 50/50 shot depending on the utility company.
Total posts : 45366Mr Bruce stated..
“What concerns me is the fact that I have a utility pole mounted downstep transformer right where my home’s mains connects to the utility company’s 1000 volt supply line. Would this isolate me from the utilty mains running down the road and make using carrier current useless for me to try? Incidently, I am on a dead end road off of a secondary road. “
I don’t think it would, and i will explain why.
Behind my house is a utility pole where the power meter and mains disconnect is, also there is a small lever switch box with a fuse inside that feeds power to a small shed on our property. Usually the power to the shed is turned off when not in use.From the pole our power lines run above the house to another pole across the road, on that pole is a transformer that feeds power to my house and the neighbors, we are the first two houses on this road.
So far so good, that little transformer doesn’t seem to affect the signal at all.
Something i didn’t consider until i started writing this post, on the end of the house where i am right now is the studio where my wife and i have our desks and computers.On the front corner of this room is where the cable tv/internet comes in to our home from the neighbors yard and from the pole in the neighbors yard is a combination of power lines, security light and cable tv. I could be inadvertantly feeding my signal to to the cable system which in turn provides the coverage you saw on my map.
75 ohm cable isn’t as effective at shielding outside sources as when it is medium grade cable, i have several pieces of this cable in a junk box after TVS Cable did some work out here. I just “cleaned up” after the tech while he was working, they said that usually scraps are just tossed in the trash anyway. This cable isn’t the most expensive stuff out there.
So it is a good possibility that my signal is using three paths to propagate, one being the power lines, earth ground and the cable tv. And yeah, i get better coverage via carrier current than over the air. You go past my house heading out of my road (remember on the map i said there is only one way in and out) and the signal drops out for 50 feet or so, as you get to the end of our road which is a t intersection, the signal jumps back in there and fluctauates between being strong to weak depending on how far away you are from the power lines/cable on the poles.
I’ll take it!
Very little effort was put into this and like i said, it wasn’t expected but i am getting coverage without even trying from a transmitter and antenna that are essentially in a large metal box. I have mentioned in the past, our house is a decent sized house but it is made up of two mobile homes set side by side where a house was built around it.The metal siding on the mobile homes is still in the walls between the wooden exterior walls and the vinyl siding, inside the home paneling was nailed to the walls and floors were re-enforced with plywood.
If it was my home (we rent) this place would be gutted and rooms would be widened a bit in the middle section of the house, but that’s not up to me and i am no carpenter.
This is a happy mistake as Bob Ross would have said.
I like it.
EIDT: One more thing, i will still build an outdoor antenna and ground system as soon as the weather and time permits it.
Total posts : 45366Well I should mention that basically the transformer’s secondary simply attaches to the 3 mains cabling that has the Neutral, Hot and Ground subscriber supply, so perhaps I wasn’t thinking about that. I can not post a picture in another person’s thread and I’m too lazy to put one up on a photo sharing site.
So, unless there is something I am not understanding about the way things are hooked up, I believe my mains has full access to the secondary road’s subscriber lines as well.
I think AM would do quite well from where I live, Google Earth indicates my back yard is 144 Feet, I guess that is either above sea level or HATT, I am not sure.
I know our local AM station is at 346 feet, again not sure if Google Earth refers to above sea level or HATT. My best direction would be to the East-North-East and North-East as I can see out to the horizion that is about 15 miles away. Doubt I would make it that far, but still very little in the way of obsticles in that direction. Otherwise, I am pretty much surrounded by man made real estate and trees.
Bruce.
Total posts : 45366I’d like to see a coupler that can work with a standard power outlet.
Craigf I saw you on our Initiative site. We are all about getting more range. Hope to get to know you a bit.
Total posts : 45366“I’d like to see a coupler that can work with a standard power outlet.”
That would make things a bit easier, however I suspect this would be extremely lossy, leaky, and might not handle RF very well.
THAT being said, I believe earlier versions of baby monitors and intercom systems piped their audio through the mains power this way.
Total posts : 45366“So far so good, that little transformer doesn’t seem to affect the signal at all.”
This is where my 50/50 chance comes in, some utility companies used to pipe data communications through their powerlines. In areas that did this the transformers were bypassed internally to let the signal pass through.
Total posts : 45366What if i just mount the SStran in a wheather proof case and mount it next to the cable box with the wire antenna running up next to the cable?
Wouldn’t it feed RF onto the cable more directly instead of from 8 feet away?
Seems like it would work despite the cable being shielded by the outer braid.Just thinking aloud now out of having nothing to do.
Total posts : 45366I’d Strip the other shield away and expose the copper center. Doesn’t have to be the entire length of the SSTran antenna, but just enough to couple a tad better. Do bear in mind this could introduce leaked RF from the cable co and introduce interference into the cable system within your home.
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