I was telling Carl that there has been a real
lot going on here, and that I wouldn't be on
the board too much right now. But here is
some CC stuff that happened.
I have all of the pieces together. The LPB
RC-6A is putting out 5 watts on 1020 now.
I changed some coil settings, and replaced
a questionable piece of coax that was going
to the watt meter. There still may be another
intermittent somewhere. I'm not completely
convinced yet that everything is right. But
it is good enough to proceed with the experiment.
The attenuator parts are on the circuit board. They
have to be soldered and connectors have to be
put on. I have the big wopping RC, and it does
tune to 1020.
I need a bunch of hours to solder, build, and
connect. But all of the pieces are there.
It's just a matter of time.
One question for Carl - hey Carl - did you say
on a sensitive car radio you can hear WSM in
Nashville during the day? How cool is that?
Best Wishes,
Bruce, DOGGRADIOSTUDIO 2
Yes Mr. Doggradio 2:
On many days and nights I can hear WSM from Nashville, and I treat that station with reverence because it is still doing what it classically always has done, broadcasting great country music.
There are times when it does not appear on my radio, but more often I can hear it.
As long as I am on here I will add a strange story titled "How Could That Happen?"
Yesterday I was broadcasting as I have been recently at 670kHz, and everything has been fine.
But this morning when I turned everything on, 670 had no audio. I was very confused at first, and began signal tracing.
I found that the + wire on the audio input to the LPB transmitter had come loose and was sticking up in the air.
Now, why did it stay connected during the previous days, yet come loose overnight?
We may have to consult with Tha Dood and his house ghost (as heard on the Low Power Hour).
In the 21 years we have lived in our house,
I have heard strange noises in our kitchen,
which could not be explained at night.
But in all of that time, it has only happened
2 or 3 times. Just a "clunk." For no reason.
But I don't believe in ghosts, so it was probably
really the pipes, or something like that.
Here is a slight continuation of
my message, because I had to
turn off the computer, and catch
a cab home from my job.
That last (above) comment was made when I
was waiting for the cab.
Now I am home, so I can end the
message.
Best Wishes,
Bruce, DOGGRADIO STUDIO 2
"It's ALIVE IT'S ALIVE IT'S ALIVE
IT'S ALIVE IT'S ALIVE HEE HEE HEE HEE"
Frankenstein - 1931
I put the my homemade CC coupler
together and hooked it up.
Power On.
6 watts forward power.
0 watts reflected power.
(With LC tuned for best
SWR.)
Perfect SWR (Probably because of
the 10 dB attenuator.)
IT'S BLASTING!
All over the house and up the street
about 500 feet!
I'M SCARED. I TURNED IT OFF!
Bruce, DRS2
I turned it back on for a few
minutes.
All the resistors in the
10 dB attenuator network were hot,
so the network is working, I
guess.
Actually, i think my initial
walk out was in the near field
(maybe) I'm not sure. I had
a really really good radio.
So it may have seemed stronger
than it really was.
All the radios in the house
are overloaded. Even the terrible
clock radio up in the bedroom
that doesn't get anything.
If you get farther down the
street it seems to fade out
in a linear fashion.
I'm not sure what is going on,
but I will call this a success
because it's getting SOMEWHERE.
And as far as I know, nobody
has tried anything quite like
this before.
Now I'll have to figure out how
well it's really FUNCTIONING. In that -
is my homemade coupler functioning
in the same sort of manner as a
commercial one.
That's going to be a difficult
assessment.
RFB. Let me know what you think
when you get a chance. There are
a tremendous amount of unknowns here.
But it sure is a lot of fun!
Bruce, DRS2
The 6-Watt LPB seems to be distributing its excess power evenly among the loading resistors, since you mentioned they are all warm, and because of all the overloaded radios in the near-field it sounds like your coupling is too efficient and needs to be "down-coupled" in some way.
You did not mention hum in the carrier on the radio and that is a very good sign that you are able to get on the power lines without 60Hz hum getting involved with your carrier.
One further test you should make is to visit the one or two neighbors so you can judge how well the signal is getting into their homes.
"All the resistors in the 10 dB attenuator network were hot, so the network is working, I guess."
You may need to put a small fan on that to keep those resistors from thermally running away and changing value.
"Actually, i think my initial walk out was in the near field (maybe) I'm not sure. I had a really really good radio. So it may have seemed stronger than it really was."
Near field indeed! However is your homemade coupler contained within a shielded enclosure and grounded at the TX's ground potential?
"All the radios in the house are overloaded. Even the terrible clock radio up in the bedroom that doesn't get anything."
I think what is happening, since you have the load/attenuator inline taking 6 watts down to 600mW, your experiencing some RF leakage out of the coupler through the air. Again this depends on if the homemade coupler is shielded and enclosed.
"If you get farther down the street it seems to fade out in a linear fashion.'
Consistent with a far field effect, and normal for a CC's near field effect if the signal is going down the length of the power line. The near field does not dissipate as quickly as a 219 setup does because our near field is being carried along the length of the power line, taking that near field down range along with the power line, whereas the 219 setup has a near field at the antenna and for a short distance, certainly not 500 feet. At 500 feet your in the far field on a 219 setup.
Make sure that coupler is enclosed and shielded at the TX ground potential. Have the coupler as close to the injection point as possible (wall socket) so that the cord being used as the secondary of the coupler transformer is as short as possible. Also select an outlet as closet to the main breaker pannel as possible to avoid excess field emissions.
I would not alter the coupler to "down-grade" it at all. You want maximum coupling efficiency and sounds like you hit the bulls eye right off. I would focus on the potential of emitted signal coming off the coupler device itself, chances are there is more signal being emitted directly from it than going into the power lines, and that would be solved with a well shielded enclosure and at the TX ground potential.
"Now I'll have to figure out how well it's really FUNCTIONING. In that - is my homemade coupler functioning in the same sort of manner as a commercial one."
To see what the secondary side is doing, you will need to build and install an SWR bridge on the output side of the coupler so you can see exactly what kind of VSWR there may be going into the power grid. This can also cause the overloading issue if the VSWR is considerably high. You may see a low VSWR on the coupler input side (primary) but on the secondary, without a way to bridge it and measure it, there is really no way of telling how that side of the coupler is working.
RFB
The coupler is on the test bench.
It is not shielded - but it will
be (somehow!)
The set-up is on the first floor
of the house and not the cellar.
The set-up is grounded to the
radiator in the room.
This is not the way it want it
to be, but I wanted to see if
it worked at all, and it seems
to.
So the changes will be made as soon
as I can.
Thank you so much for your note!
I'll be getting back to you.
Bruce, DOGGRADIO STUDIO 2
my trip to rhoadescar factory in Tennessee stopping at 650 am wsm nashville
The pictures from WSM are really good to see. What an impressive looking tower they have.
On a comment made by RFB on the "Scored Again" thread I got a whole new idea.
My house is the last house on the power transformer which feeds the lines being used for my CC operation, and all the houses eastward are on the same line.
But the house right next door on the west is on a different transformer. I know this because when I have a power failure they don't, and when they have a power failure I don't.
So, if I could get a drop from that other nearby transformer, I'd end up with two electric meters, and I'd be able to feed CC to a whole additional row of homes.
But of course it would be necessary to use a different frequency to avoid cross-talk interference, right?
in my opinion wsm 650 is the last of real radio on a licensed station in this country. and one of the very few am's who take care of their am facilities and i believe the only one with a blaw knox fed by a ladder line feeder
"So, if I could get a drop from that other nearby transformer, I'd end up with two electric meters, and I'd be able to feed CC to a whole additional row of homes."
Usually the utility won't do that for various reasons. Each grid or blocks of grids will have their own neutral off those step down transformers. A high probability of voltage potential may exist between those two or more neutrals in reference to Earth ground.
Solution here is to run a power splitter (RF) and feed two couplers. If the next door neighbor is willing, install the second coupler on their breaker panel including installing an isolated Earth ground rod and there you go. The coupler itself provides the isolation because no where within the coupler does the input have direct connection to the output.
"But of course it would be necessary to use a different frequency to avoid cross-talk interference, right?"
No.
RFB
It is valuable to learn about the hazard involved with having two different electric feeds from different transformers, because of yet another reason why I've thought about that other feed located just next door...
When those power failures occur I have often looked next door and there they sit with lights and heat and refrigerators humming....
On the other hand when I'm the lucky guy I have thought of handing an extension cord over the fence as a neighborly gesture, but now I know better. Not such a good idea.
As far as putting a coupler at their panel, that is an interesting thought. What we need is something to barter so they get some benefit out of it. I'll be busy thinking about that.
Carl! Somehow I missed your comments. Thank
you for letting me know what you thought.
And Carl, I may have a similar situation
as yours. I believe my house is not on
the same circuit as some of the other
nearby houses. I'm not completely sure
about this, but during that big storm
in the fall, a lot of houses lost power,
and so did we. But a lot of houses got
power back before we did. We are on a
main street, and might be at the end of
one grid and the beginning of another.
No matter. I am very happy with the
experiment so far. There is very little
hum on the radios in the house, also.
Before I say more, I want to put in a
plug for the wonderful pictures of WSM
from Robert, KC8GPD. I too, think a lot
of WSM. It is a very very special radio
station.
Back to my CC experiment. There is some
RF coming off of the LC network. But
my cruddy little CB/ham field strength
meter has given me a few clues. There is
not nearly as much radiation coming off
the LC as there was from my Part 15.219
three meter stick. In fact, there seems
to be quite a bit less, although there
is right now no way to convert that to
meaningful data.
The uniqueness in this approach is the RF
attenuator and the fact that the extension
cord is just wrapped around the LC. (This
is the extension cord that is feeding the
CC transmitter.) And for those of you who
haven't seen too much writing on this
experiment, (I'm going to say this loud.)
THERE IS NO DIRECT ELECTRICAL CONNECTION
FROM THE TRANSMITTER/RF ATTENUATOR/LC CIRCUIT
TO THE A.C. LINE! That's important to remember.
Again, the AC cord feeding the transmitter is
just wrapped around the big LC.
I just realized I can take the AC cord feeding
the transmitter out of the line and feed power
to the transmitter from another extension cord,
with everything else remaining the same. This
MIGHT provide some clues as to how much RF is
coming out of the coil and how much is going
into the AC line. I might be able to get some
clues by making this change.
Shielding the RF attenuator network is no
problem. I have metal enclosures for that.
That LC is another matter, though. That
will be a lot harder. It may come down
to a box wrapped in aluminum foil and grounded
to TX ground.
By the way, I was just barely able to construct
this thing. My eyesight was not good today.
However, the experiment came out pretty good and
I was able to check everything appropriately
before I powered the thing up.
When I put this in the cellar near the breaker
box, there will be no way I can put a metal
pole into the ground. It is my figuring that
connecting the TX ground to a water pipe is
OK. The reason I say this is because the
TX is FLOATING ABOVE GROUND. I hope this
makes sense.
IF ANYBODY ELSE TRIES THIS, REMEMBER THERE
IS NO DIRECT CONNECTION FROM THE TRANSMITTER
RF OUT TO THE AC LINE! IT IS ALL JUST COUPLING!
I DON'T WANT TO SOUND LIKE A LOUD MOUTH, BUT
I WANT THIS TO BE CLEARLY UNDERSTOOD!
OK. I'm done yelling now. By the way, I am
an almost legally blind dude with very little
engineering experience. And although I have
done a small amount of radio engineering work
it was just a little years ago.
So if I walk into the other room and this thing
starts smoking and blows up, you will know that
I messed up somewhere.
Thanks for reading this!
Best Wishes,
Bruce, DOGGRADIO STUDIO 2