I went down to a friend's house
14 houses down the street.
It was an spontaneous thing.
I had a Grundig S-350 with me.
I didn't expect any results.
But I can hear my station in her
house on my Grundig S-350. It's about
1000 feet away, and like I said - about 14
houses.
It was a battery powered radio. the signal
only came in on the side of the house where
the power line comes in. So that's proof
that this is working CC, and not going
through the air.
The signal was not that strong, but again,
this is just the beginning! When the time
is right, I will go back with a "plug in to the AC"
radio.
This is a BIG deal for me.
Best Wishes,
Bruce, W 60 HZ
"W 60 HERTZ! IT ACTUALLY WORKS!"
That was very rewarding to hear your CC signal on the radio in the neighbor's house.... you are rewarded for your design work.
Thanks RFB for posting the LPB stuff. I went and looked at it for 15-minutes while I debated whether to bid, but I made a decision that 30-Watts is way more than I need and that for my 2nd CC venture, which will be a daytime only station at 660kHz, I will probably build about a 5-Watt transmitter.
I know this has been covered before in conversations with RFB, but I am going to repeat the whole process because I am fascinated by the subject.....
I once asked if I could inject two CC signals into the same electric service, with two transmitters and two couplers, by connecting one by neutral injection and the other by power-line injection.
I know that your answer was that a mixing-circuit would be needed to isolate the two signals from getting into each other's transmitters, BUT....
Elsewhere you said that the torroids prevent AC hum from backing up into the transmitters, therefore, wouldn't the torroids also prevent RF signals from backing up into the transmitters?
What your looking for is a combiner, except with the connection configuration your proposing, that combiner would have to reject the signal on the neutral but at the same time allow the other to use that neutral as a return.
Be a lot easier to just combine and reject each signal to the other and feed it all into the neutral.
The other way would be like expecting a vertical monopole to be a ground plus a radiator. Similar setups such as an MW tower with an FM hung on it, the notch/tuner does something similar to what you will need for your neutral/hot two CC setup.
RFB
Carl, with 2 signals, you
might have to share time.
This is a joke, of course.
What RFB is saying is right.
This does remind me of 3 or 4
stations in Chicago that shared
1240 for decades. 3 or 4 separate
transmitter sights, 3 or 4 antennas,
whatever it was. It's an amazing story
anyway.
Yup, I'm happy about this result. It's
very very interesting.
Bruce, W 60 HZ
I'm thinking of actually going back
on the air. For starters - Saturday
and Sunday from 6:AM to sunset.
I'm thinking about this because of
today's success with the CC set-up.
I have the potential to have an
audience now.
I made one change with the coupler.
I have some notes sitting around here
that are very old. These notes mention
loading up the AC line with a 10 uH
inductor. Theses notes said the coil
would have around 37 ohms of reactance
on the AM BCB. But the frequency is
unknown. I put a 10 uH coil in anyway.
(I made it.) Out at the telephone poles,
the signal might be a little louder, it's
hard to tell. The coil did not make
things worse. I did notice one thing.
Before, the clock radio upstairs was just
hum when I tuned into my signal. Now the
hum is very low and there is a lot more
audio. The hum on the portable radio in
the house is less, also. I have no idea what that means.
Here is my stupid question. It concerns the
above 10 uH coil. First of all, at 1020 kHz,
it's reactance is probably not 37 ohms.
Also, shouldn't the reactance be tuned out
somehow? I thought reactance was an
undesirable factor in all of this.
More ideas to come.
Bruce,
W 60 HZ - - AM 1020 CC
at the telephone poles.
Now to put this hot little
transmitter into shut down.
Bruce, W 60 HZ 1020 AM CC
Don't worry RFB. I'm
not going to stop developing
this coupler. I will keep
working on it.
How do you measure SWR on the
line side of the coupler? Do
you just use a regular SWR bridge,
or is there some other way to do it?
Bruce, W 60 HZ
More adjustments.
So here I am outside in
my goofy bright yellow raincoat
trying to look discrete.
Going up to telephone poles, checking
the readings on my Tecsun PL-380.
1000 feet away, the reading on the
PL-380 is 63 dBu and 25 dB S/N
ratio, whatever that means. (I know
you guys have explained this stuff,
but I have to look it up all over
again.)
But I guess what I'm trying to say is:
1000 feet away on that telephone pole,
the reading on the PL-380 is as high
as it can go. At the telephone pole
beyond that, there is NOTHING. Interesting,
huh?
I yelled "good morning!" to the guy at
the bus stop, about 30 feet away.
He turned and looked in the other direction.
Bruce, W 60 HZ
Going up to telephone poles, checking
the readings on my Tecsun PL-380.
1000 feet away, the reading on the
PL-380 is 63 dBu and 25 dB S/N
ratio, whatever that means. (I know
you guys have explained this stuff,
but I have to look it up all over
again.)
Bruce, under FCC §15.221, a carrier current system operating on 1020 kHz is limited to a maximum field intensity of 15 µV/m at a distance of about 154 feet from the a-c line.
That field intensity is below the r-f noise level outside of a screen room. An AM signal having that value of field intensity would be unusable to AM receivers located in a normal listening environment.
I have a PL-310, which uses the same microchip as the PL-380, and provides the same display of "signal strength" and S/N. When I tune it to 1040 kHz (daytime) it picks up WHO Radio from Des Moines -- who has a known field intensity of about 500 µV/m at my location. The PL-310 display shows 27 dBµ with a S/N of about 10 dB, with the receiver oriented for highest readings.
So if your PL-380 is receiving a 63 dBµ signal with a S/N of 25 dB when located 1,000 feet from a radiating power line, this will give some "calibration" to the performance of that system with respect to FCC §15.221.
Hope this post is not considered to be "anti Part 15."
The reason that the guy 30-feet away turned in the wrong direction when you shouted good morning was that your voice carried past him, bounced off a wall on the other side, and came back. You accidentally used ventriloquism.
The second number on your field strength reading, 25, is full quieting on the AM band. That's the S/N, the "signal-to-noise", and on the AM scale 25 is maximum signal above noise. That is good.
The other reading, the field strength, 63dBu is very good. Compare it to full power stations in your area. They will probably range from the 30's up through the 60's, unless they're very near by, then they could get up into the 80's. Anything in the 90's means you are in the transmitter shack.
Also, for comparison, get a field strength reading near your transmitter.
"Bruce, under FCC §15.221, a carrier current system operating on 1020 kHz is limited to a maximum field intensity of 15 µV/m at a distance of about 154 feet from the a-c line."
That's right. But I will guarantee you this...if his signal is a few microvolts above 15 at 154 feet, the FCC isn't going to stop the press and break out the violation pad...not when they got 16 year repetitive licensed violator/s committing fraud and perjury.
Bruce is working with a home made coupler, so he is bound to get a signal strength a bit more than normal from a commercial coupler and the fact that the signal is without a doubt radiating from something more than just the utility lines.
He is still in the discovery/experiment mode.
"Hope this post is not considered to be "anti Part 15."
I don't think it is. I think it's a good refresher for those already well aware of the limits for 15.221, or any other Part 15 rule. I don't know if the newbies would find it useful though. :p
RFB
Thank you so much you guys.
And Rich, it's all good. Nope,
your statement is not anti Part 15.
Yeah, this is an evolving coupler.
As long as it doesn't turn into
a tyrannosaurus rex, I think I'm OK.
(Have you ever tried to clean up
after one of those things.)
I must have been sheer luck that the
coil I made loaded up the AC line
in what seems to be - close to what
I am looking for.
After the near field, there is some
radiation from the power lines, and
then it completely goes away.
I believe I'm compliant. Still:
With me, it's "test test test."
Drives my wife crazy.
Bruce, W 60 HZ
I want this to be a really
good coupler.
We will be moving and I want
it to work wherever we end up.
So I plan for it to be very
much like a commercial one
when it's done.
This will take a while. I want
to learn about this stuff, mainly.
If I can build one, I can build
several. How's about if a logic
circuit switches between couplers
to the best one for the situation
that comes about when the line
impedance changes.
Or just throws relays into some
different parts in the cabinet.
My RC-6A has a bright neon light
that indicates when the system is in
resonance. Right now, that light
is shining brighter than I have ever
seen it. Put a photo cell next to
it... Feed that to a logic circuit...
You've got a control system to
follow line Z changes.
Will it work? Who knows? I will
probably never get that far.
Bruce, W 60 HZ
Last night, I was going
to measure a section of
sidewalk, and then use
that as a reference to
figure out distance.
This would be to check for
compliance and other things.
But there were too many people
around. I was going to go out
today, but we are getting a storm
with snow and sleet and rain, and
other small particulate water things.
It will have to wait.
This is getting more and more
interesting.
Bruce, W 60 HZ
That weather you are getting on your side walk must be the Nor Easter.
I think I know what that means....
Carl celebrates neither christmas nor easter.
Then it snows and the wind blows.
Would you people mind stepping off of this particular side-walk square so I can measure it? I'm with the sidewalk inspection office.