From what I can tell, my carrier current signal
is just on my street and that's all.
But I'm on a very long street, and
I think the signal is theoretically audible
in 40 or 50 houses, and that's with
500 mW going into the line.
I think I can explain why the signal
is just on my street. Across the street
on the other side is a high voltage distribution
line. The way I think things are arranged -
I believe this is why the signal is just
on my street.
This is acceptable to me for now.
Because we will be moving, in the
next place we live, it will be a
whole different game.
I will be continuing to work on a
tunable coupler that is shielded
and will not radiate.
And if that works, I will go from
500mW injection to 5 watts.
As I work on this experiment, I may
lower power by another 10 dB, from
500 mW down to 50 mW into the line.
That way, as I work on the coupler,
if it radiates - it will not be a
problem with Part 15.209. (My observations
seem to verify this.)
So, the long term plan is to probably drop
power to 50 mW injection and work on the
tunable coupler. Then I will go to 500 mW
injection as things get worked out. Then
I will go to 5 watts injection when things
are ready. And then the biggest problem to
solve is to go from 1020 kHz down to 620 kHz.
I want to be on 620. That will be the hardest
part.
Bruce, 1020 CC
The reason carrier current transmitters are built with variable power controls is that every power line match turns out differently.
My system efficiency is so good that I'm only running 1/4 Watt, which is only 250mW.
Bruce, if you get good coupling at 1020kHz you may not need 5-Watts.
Use your TECSUN PL-310 to check your relative field strengths, assuming you have a way of viewing the tiny number display.
Mine is rarely on for more than a few hours, since I'm still studying what the rules actually require.
Still haven't done the grass.
Thanks for the comments about
my new CC experiments and how
your studies relate to mine.
And I will take my Tecsun radio
out and check again. That's a
REALLY good idea. It's hard for
me to see the visual display,
but I can see it well enough.
I am a low power
kind of guy. I'll be bringing
the injection power down to
50 mW by making another 10 dB
attenuator and putting it in
the line for these coupler
experiments.
But before I do that:
I want to try and get over to
my friends down the street and
see if the signal is actually
getting into their house. (My
Part 15.219 signal was heard in
their home by one of them on
some kind of boom box radio. That
was when I was using the Ramsey
AM-1 transmitter modified for crystal
control.)
If it really is true and my signal is
getting into THEIR residence, then, based
on what RFB has said about how CC
propagates down the line - and based
on my measurements - I will have
good reason to believe that the 1020
CC signal REALLY IS getting into 40 or 50
houses.
We'll see. I was optimistic - but
when it really comes down to it -
well just have to wait and see.
Somehow it seems to good to be true.
I'll talk to my friends soon and get
over there, and then we'll know for
sure.
Bruce, 1020 CC
My friends weren't home.
(In case you just tuned in:)
I had gone down to a friend's
house 800 feet away to see if
they could get my carrier current
signal.
When I saw they weren't home, I
looked around, and noticed that
their electrical meter is on the
front of their house right next
to the front door. There was
no sound on the radio, but when
I put the radio up to the conduit
that contains their house AC line,
I heard my CC signal. This is
encouraging, because it means that
my signal is in the line that is
going to their power meter.
The signal was clear, but I don't
know how strong it was. (I didn't
want to hang around for any length
of time, because people would start
wondering what I was doing.) There
was also a bunch of buzz on the signal.
The AC overhead wiring on the street
is sometimes very noisy, so it made it
harder for me to assess the strength of
my CC signal.
But anyway - my signal is on the line
going that goes into their house.
Now I just have to wait until they
can have me over for a few minutes.
I'll plug a radio in an AC socket
in their living room or kitchen, and
hopefully - the signal will be audible.
If it is, I wonder how strong it will be?
Bruce, 1020 CC
P.S. This house is 8 houses away from mine.
"The signal was clear, but I don't know how strong it was. (I didn't want to hang around for any length of time, because people would start wondering what I was doing.) There was also a bunch of buzz on the signal. The AC overhead wiring on the street is sometimes very noisy, so it made it
harder for me to assess the strength of my CC signal."
AC line noise, particularly on the HV lines, attracts a ton of garbage and inductively couples that junk and sends it down the lines everywhere. Then include the induced noises onto the lines by consumer devices. These "Energy Saver" squirrel tail lights and switching power supplies all add to the mix mash of noise a CC system must deal with.
It's not easy sometimes, as this buzz noise can be at various points along the MW band. Some rather weak, while others are very strong, and it will vary in it's position in the MW band throughout the day and night.
The ever changing loading characteristics of the AC utility lines is also a factor and plays in the role of how much garbage is on those lines. A CC system must deal with that as well.
CC is a very unique form of radio transmission since it relies on those noisy lines, and can be quite difficult to work with even so and sometimes worse when confining the signal to just a single building. The building will have it's own contribution to the headache, plus whatever is coming in off the AC mains feeding the building.
There is no such thing as a single shot fix or solution. Every single location will have it's own unique properties and problems. Unlike a monopole system where it can be predicted by simulation as to how the system will perform, a CC system is even more difficult to try to simulate due to the incredibly wide variable of junk on those utility lines.
The best approach is to simply experiment and find the right combination that yields the best performance of the CC system.
Keep at it Bruce! 🙂
RFB
Good to hear from you. I have
been enjoying your progress on
the other thread!
I am really really enjoying this
CC thing.
And, I think, this is really the
first time I have a signal actually
going down the AC line. Before, it
really wasn't.
So I will keep building on this. I
don't mind all the glitches. To me,
they are part of the fun.
I have the RC-6A open, so it can breathe.
Those glowing tubes really look cool.
Thanks again for your comments. I will
very much keep them in mind.
Bruce, 1020 CC
Tonight at 6 PM as the storm raged and the dial was filled with static, I turned on the CC and raised the power from 1/4-Watt to 1-Full Watt.
The dBu reading (TECSUN PL-310) at my desk on the main floor of the Internet Building went from 80dBu to 90dBu.
Because of heavy rain I took no outdoor readings.
This is a test mode, as I still don't completely understand the strange trail that unfolds while trying to follow the CC rules from one point to the next.
No matter. Just like Bruce, it is a hobby and a curiosity and a fun experience. No real business plan at all.
"I still don't completely understand the strange trail that unfolds while trying to follow the CC rules from one point to the next."
It's quite easy. Simply find the distance point to meet 221 away from the line, and proceed along the length of the line at the distance for your frequency per 221 to make sure the signal does not go past that distance from the line.
Think of the line like a leaky coax, the signal can only go so far away from that line no matter how long it is.
RFB
Using neutral injection I am not sure the signal is actually on the power lines, I think it's the 3rd wire, the ground/neutral line and the earth itself are the two points and it is not obvious what I am supposed to measure X-feet from, since there are lines of all kinds going in all directions.
Well the rules state distance from the source, that being the injection point. So after that, the signal should be only receivable a few feet away from that 3rd line/ground wire on the pole, which decreases the further down the line the signal can travel. If that signal has a good direct path along the 3rd line and into the drops, there is enough signal there to be received by a radio.
RFB
...On a busy street without looking
like a nut.
You have to have a radio that is close
to the size of a cellphone. Then you can
go down the street and make believe you
are talking on it. (In other words, you
are making believe the radio is a cellphone.)
Hold it up to your ear, talk into it, and
then casually lean up against the telephone
pole and listen for the signal.
I am trying to do this on a street that has
about 2000 cars going by every minute.
The cars are making too much noise.
More data to follow.
Bruce, "W60HZ 1020 AM Carrier Current"
I have pretended that a tv remote control is a cell phone, but there would be very little point in pretending it was a radio.
RFB posted, in part: Well the rules state distance from the source, that being the injection point.
Could RFB or anyone else mathematically/legally prove that the source for a compliant FCC CC system is located solely at the injection point?
The dominant source of radiation for AM systems legally operating per Part 15 CC Rules is the a-c power line network physically nearest each AM receiver.
Does that suggest that the CC radio station is required by the FCC to measure the radiant leakage from points near every AM receiver that is proximate to its nearest AC?
Hi Guys!
Yup, I am trying to figure all of this
out. RFB's statement seems to makes sense to me.
That is the point where the most RF energy
is involved. It seems to me that you would
measure from there, and not in another place.
That's why he has always said that shielding
is necessary. You want a minimal amount of
RF to get out into the air.
I can tell you this:
My near field is very small. Part
of the reason may be that only 500
miliwatts is going into the AC line.
Probably quite a bit less, because
the feed is not well matched as far
as SWR is concerned.
(The 10 dB attenuator takes the 5 watt
RF out from the RC-6A and drops it down.)
(And I plan to drop down to 50
miliwatts soon for further tests.
That way, I can design an RF tuning
circuit for the coupler that can
be very small - to start. I can make
it larger for later, when I increase
Power.)
(I am so conservative with my FM
signal, it really doesn't go
anywhere except in the house. I
had a friend visiting from California
a few years ago, who also had a
Part 15 station. He listened to
my FM signal and said, "Gee, Bruce -
you can let it go a little further
than THAT.")
After the near field, the AM 1020 signal
is heard next to telephone
poles about 1000 feet east
of my location. To me - this alone
is a great accomplishment! Actually,
that's about 25 houses right
there. (If the signal is really
getting into those houses, and if
it's strong enough for a typical
radio to pick it up and have it
be listenable.)
I still have not been able to
get into my friend's house and
see for sure. And I have not gone
in the westerly direction with my
portable radio yet. The signal is
not on the streets parallel to mine
at all. In other words, it does not
go north and south in any way.
This thing is just an experiment now.
I'm going to have to go back and read
a whole bunch of posts and look at
the FCC rigs to completely understand
all of this. I also have to read
up on theory more. I'm not the sharpest tack
in the drawer. I have to read things
over and over so they sink in.
My near field complies to
Part 15.221 (not Part 15.209
as I mistakenly said before - and I
made that mistake several times.)
I'm in it for the science and to look
at the glowing vacuum tubes and to feel
like I'm young again. Seriously, the
"feeling like I'm young again" is very
important. Our family situation
being what it is, I only have time for brief tests.
Some day, maybe this will be a Part 15 station,
but it probably won't be until after we move.
Here's the humorous part.
We get in the car. I tell my wife I'm
going to track my station. We go about 150
feet and it's gone. Then she says to me:
"I thought you were tracking your station."
And I say, "I am, but it's in the power lines,
and it's not going through the air. It's
something else I'm trying now."
Then she just says, "Whatever."
There is another consideration here. I am
running a 41 year old vacuum tube transmitter.
(I do it because of my love of antique radios,
especially those with vacuum tubes.) But - this
transmitter might not really be able to run
for extended periods of time. It IS old.
If this thing continues, I may have to buy
of build a solid state transmitter.
Bruce, "W Sixty Hertz" 1020 CC
P.S. The callsign W60HZ" is strictly
for the humor. I just needed to have a
name for this experiment.
P.P.S. As is typical for me, this post
is very "wordy." I'm a motor mouth. I
hope there aren't too many misprints.