Makes me think of the TIS that do around 10 watts the same way. On that note, and not meaning to change the subject at all, maybe we should file a Petition to the FCC to allow local programming from a TIS station to create low-power AM. However, this time, let's make it so we can sell commercials.
I would love to hear an explanation of how "neutral injection" works. It is claimed that it promises greater range because it bypasses the power transformer (neutral doesn't go through the transformer). But, this injection method doesn't seem to make sense when you look at the wiring inside the house.
The National Electric Code standards mandate that, in a building, the neutral bus is to be bonded to the building ground (ground rod, water pipes, etc) in the "service disconnect" box. In most homes, there is no separate service disconnect box, just one big box with a main breaker and the distribution breakers. In this case the neutral bus is tied directly to the ground bus with a short wire inside the box. So connecting a CC coupler to the neutral bus is equivalent to connecting it to ground.
The LPB documents in the library "PDF reading room" here on this site show connecting the coupler between neutral at an outlet and a rather vague "Earth Ground NOT AC RECEPTACLE" point. I think I remember RFB saying that this vague ground point should be a separate ground rod located a distance away from the house. If I'm correct, then the load seen by the coupler is a circuit consisting of, on one side, the neutral wire from the outlet to the breaker box and on to the building ground rod, and on the other side, a wire to that extra ground rod. The circuit path is closed by whatever ground resistance exists between the two ground rods. That circuit path doesn't include the neutral wire going out to the pole!
I can understand radiation occurring inside the building from the wires included in this circuit, but how in the world would it get past the ground at the service entrance on the way out to the power lines? That wire isn't in the circuit. Maybe some would get through due to stray coupling between wires, but I wouldn't expect anything significant.
I can certainly understand injection into the both HOT wires. That's similar to driving crappy transmission lines out to all the house wiring, and likely to other houses sharing the same transformer, but not beyond the transformer.
It seems that the "neutral injection" equivalent circuit would vary anywhere from a dead short to maybe several dozen feet of wire throug ground depending on where you connect the coupler relative to the breaker box. In any case the circuit path doesn't include the neutral going out to the pole. I would say this is all baloney and is part of the reason LPB went out of business, but I won't say that if someone can point out what I may be missing.
What you say makes sense at first, except that rf energy does get down the pole. I have read with interest that many people can pick up the signal closer to the line two or three miles out. Maybe tons of rf is wasted overloading your house radios, but it does get out somehow. Combine that FCC given right with the free radiate right and use the same pll and it could be legal. Maybe something like a 3 watts into a line.
Even if the rf only gets to a few houses... combined with a synced antenna system and coverage could be great. Doesn't every milliwatt of RF count? Won't it all add?
As one who is connected in a neutral injection arrangement set up just as PhilB described, I would be very skeptical myself except that some how it is working well.
Looking at the way it's wired, I would expect very poor results. The RF output from the coupler is run into the electric panel and connected to the neutral buss, and indeed that buss is strapped to ground within the same panel. The panel ground has a heavy cable that runs outdoors to a ground rod planted by the electric service company that installed the panel. The electric panel also has a heavy copper wire run across the basement and grounded to the water pipe as it enters the building.
The coupler ground is connected by wire out the wall to a privately planted ground rod, only about 1.5' from the electric service ground rod.
Yet a very strong RF signal can be traced along the 75' of my electric line to the pole on the street, and the hot range is from 150mW to 3W, above which radios on the property saturate, although the RF near-field strength drops at each pole heading down the street.
I'm estimating that the secret is in the low impedance achieved by the coupler, and tuning the coupler to minimize Standing Wave.
The overall result is a neighborhood signal just about equal in coverage to a radiating part 15 transmitter.
"I think I remember RFB saying that this vague ground point should be a separate ground rod located a distance away from the house."
Actually what was said was "isolated" ground as close as possible to the coupling point. Using standard solid copper ground wire and ground rod/s. The more ground rods the better for a larger contact to the dirt. The reason why it should be short as possible is to minimize any signal emissions from the ground wire.
The optimum neutral coupling point would be above the breaker box where the service enters the home. However that isn't recommended due to safety. Thus coupling to the neutral buss inside the breaker box works just as well.
The neutral line goes out to the utility pole and connects to the neutral line up and down the high tension lines. The ground wire that runs down each pole acts more like a stand-off than a conductor to the signal, but some will travel down that ground wire. The rest continues along that neutral line until it either encounters a break (different grid segment) or the signal simply becomes weak as it makes its way down that line.
What is being created is a "loop". A very large loop. The return path is through the dirt and into the ground rod/s.
Don't forget that those couplers will match to a .1 ohm and less load without a sweat.
"I would say this is all baloney and is part of the reason LPB went out of business"
LPB did not go out of business. It was sold to a very unwise ownership who didn't know what they had or what to do with it and literally destroyed it. LPB was in business and doing very well until that happened. It had nothing to do with your assumption that it was all baloney.
You have to consider that this same technique along with hot coupling was used over 80 years ago and still works today. It's easy to get confused as to why it wouldn't work because your not looking at the different coupling techniques except for the hot method.
Take a DVM and run a continuity check between an isolated ground and a neutral buss in a breaker box...and see for yourself there is no short.
RFB
"I'm estimating that the secret is in the low impedance achieved by the coupler, and tuning the coupler to minimize Standing Wave."
Bingo. Though it is no secret. It only seems that way because those who discovered it were shrugged off as being crazy or the technique was considered...baloney.
Obviously it isn't..because it works.
What I suggest to the naysayers is to actually put one together and study it very carefully and learn something besides trying to force it out of a simulator.
Since there are a few here so hell bent on attempting to discredit and disprove something they have absolutely no knowledge of or experience of..I'm done with this one way good ol boy place.
Anyone wishing to have hassle free discussions on the subject or any other can do so at my forum, where it is free of this crap.
Good bye Part 15.us. It WAS a great place.
RFB
Don't go! We need you here sir. I can tell from reading many many posts that you have educated us all!
In fact... I need your guidance right now.
How do you do an isolated ground? Was gonna ground to the water pipe, but I guess that's not a good idea!
I'm still having fun.
And that goes for all of my operations,
as peculiar as they may be, (judging from
some of their names)
because I think they are fun, mainly
That's:
1590 or 1690 with the SS-Tran
W 60 HZ, AM 1020 CC
Good ole
GNAT 90.9
SLUG 88.3
and
X-13 on 13.560 MHz
They're fun.
Bruce
My original motivation for this thread was curiosity about whether CC really works when sourced in a home because that is how most people here would want to operate. I only wanted to know if there was a real prospect that it would actually propagate beyond a home and the power transformer. I also was particularly interested in how neutral injection works from a theoretical viewpoint. Again, I think most people here would be more interested in neutral injection because it is easier and safer to implement and has that promise of propagating beyond the transformers.
I'll let the subject drop due to the controversy. I'll defer my curiosity to another time and place.
I don't really know how or
why my 500 mW into the neutral
went out to a house about 15
houses away. (I mean - not
entirely, anyway.)
It just did.
Best Wishes,
Bruce, Lot's of little Part 15 stations
I'm still attempting to understand why some got so upset over this topic!?
I don't know. We have
some really really REALLY
talented people here.
But setting that aside for
a second, and trying to make
my own conclusion, I just think that
a CC signal goes where it
goes. I've heard stories
about CC set-ups covering
entire towns several times now.
It must just be the way the
community is wired.
In my case, I only have proof
that my signal is getting into
one house that is fairly far
away - but that same CC signal does not
get into a house that is closer.
My house was built later than some
other houses on the street (1931) so
that may be why - maybe there's
a separate circuit for my house
and some of the others.
Best Wishes,
Bruce, W 60 HZ and other experiments
well this whole thread was unnecessary and was either intentionally or unintentionally designed to provoke a flame war. [edited] we are all here to understand part 15 better and the technical side of things and share our experiences and results of experiments and not be belittled attacked or flamed for them. [edited]
we need things moved forward in a positive manner and not bash peoples experiments and discoveries.
I hope JP or neil will archive amd lock this thread. there is nothing here that can be posted more in this thread and it can only spiral down from here on in.
there is already a C-C thread where technical aspects of C-C can be continue to be discussed. [edited]
[this post was edited. Questions or comments about forum users or moderation should be handled privately using the CONTACT feature in the left panel. Posters have been requested to do so in the past and are now reminded of this. Neil]
I don't see anything wrong with the OP, why is it forbidden to question the usefulness of carrier current? And are egos so fragile around here that someone threatens to leave over it?Personally, I found the discussion interesting and certainly not negative. Or provoking.