I’ve looked over the rules for AM band CC broadcasting. The inference from some here have made it look like CC broadcasting is only for education campuses, but, in fact, there are no such stipulations in the FCC regulations governing CC Broadcasting.
Therefore, I’m going to go ahead and start working towards the goal of establishing a CC broadcast station, which will hopefully help solve the problem of getting my programming into buildings in downtown Friday Harbor. It will be at the low end of the band of course, right around 610kHz, which is very far from the 1650kHz used for the stick antenna, and should pose no problems for interference with each other, and so they need not be sync’d.
I can use some help, other than the LPB manuals, which are great, but a long ways from describing what I’ll need to do in, say, a 4- or 5- block square area without o many cable runs. I’m … hoping RF Burns can continue the blog started back in March.
look in the library under
look in the library under lprc tech page. there is a wealth of info from rev. cunningham and earnest g. wilson on carrier current including some easy to make transmitters for 5, 10, 50 watts from tube to solid state and also carrier current couplers. i’ve never tried but its my understanding carrier current is more of a try it and see what works things then actual science.
CC
Actually CC broadcasting became quite an actual science back in the hey day of the early 40’s. Many hams might frown upon your comment there about it not being an actual science, as hams of that era, and in many others, drastically improved upon the technique after both the telco and power companies used CC for their communications across their own wires.
As history documents, over the air radio transmissions were banned during WWII in the US. It was the hams that took the technology and came up with the techniques to effectively couple the signal to the power lines, as well as done all the trials and errors….wow…pretty much like how real science works eh?!!!
Science works like this…..first there is a theory…then an experiment to support said theory….then the experiment…if successful..is repeated by others to attain the same success…if it is successful….the theory becomes accepted as a scientific fact.
Since CC broadcasting has been successful…otherwise companies like LPB and RadioSystems would not have made all those transmitters and couplers….there must be some solid ground to the technique.
Now what makes CC a bit unconventional is the fact that not everyone’s power grid is exactly the same. Slight differences in how the power distribution system is laid out on the power poles and under-ground hell holes. One method might work ok in location A, but in location B, that method does not.
If you want some tips on CC, feel free to contact me.
ô¿ô
A Little Help Here
Carrier current could cover a large area with the cooperation of your power company.
They would need to install RF bypass capacitors to feed the RF around the distribution transformers as the RF would be stopped at the transformer.
Without the bypass capacitors, your signal would reach radios on the same side of the transformer but not beyond.
There has been much discussion here about “neutral injection” where the RF is connected between the neutral and a separate earth ground.
Seems to be problematic though as the neutral is grounded at numerous points along its path.
An old reference source for carrier current suggests making the neutral connection where the service connects to the house, some distance from the distribution panel. The idea being the length of wire from that point to the panel would provide enough impedance to allow the RF signal to flow out the neutral rather than straight to ground.
Sounds more like an untuned long wire antenna than carrier current.
Welcome Home RFB!
Just this week I was on your website looking at your very active operation but wishing you found the time to visit back here at the old hang out.
Want to do a Carrier Current Part 2 show?
I’ll e-mail in a few days.
KDSX Is Carrier Current
My Station KDSX 88.7 FM Is Carrier Current Operated Transmission. the transmitter was only 20 bucks and 100% full deal Value to it and I’m still satisfied with it myself, going on 2 Years Strong.
More..
To an extent…depending on the coupling technique and coupler type…the neutral connection can be more or less a long wire. But lets not forget that the long wire is connected at various points along its path on the poles to ground…the copper wire run down the poles, or if the pole is metal, the pole itself serves as the earth ground connection.
This is why it is important to use a “real” coupler unit such as that of LPB or Radio Systems. These provide the proper tuning and coupling to the line.
Remember that CC broadcasting is basically creating a “loop” circuit for the RF signal. In the conventional mode of coupling to the “HOT” lines, your using the secondary winding in the pole transformers to form your loop. In the case of neutral coupling, the loop forms between that neutral line and whatever grounds are attached to it along the path AND the separate isolated earth ground!
It is a bit difficult to wrap the head around and understand how it would work since the neutral line has ground contacts at various points. Basically those ground connections server more as “stand-offs”. Yes they too will have some of your signal on them and taking it to ground through those connection points, but not so much that your signal ends up dumping completely at the first pole.
Also keep in mind that CC broadcasting is not the same as intentional radiator. The signal rides on the line and goes as far as the line runs. As long as the signal riding on that wire conforms to the 15uV/m @ 30m, which can be well over 250 feet at the lower MW band, your perfectly legal.
Now it is possible to go beyond that limit simply by increasing power, but what is the point of that? After all, a 15uV signal into the front end of a super-hetro receiver is considerably high…enough to a point of receiver front end saturation.
My advice is to use the techniques proven by LPB and Radio Systems. To connect a length of coax and its center conductor to the neutral line at the drop via some inductor and isolating capacitor is really not the proper way..although it can and does work. What the problem with that is the fact that even the neutral line changes inductance with the load variances. Remember it is carrying return currents and is just as prone to change inductance as the hot lines.
A proper coupler, such as the LPB TCU-30, TCU-8, and Radio Systems coupler, provides not only just the correct way to inject the RF signal onto the line, be it the hot line or neutral, the couplers also maintain proper transmitter impedance loading no matter what changes take place on the lines your coupling to. A simple capacitor/inductor scheme does not, and is why the early coupling units that did use bulk tuned components required constant peaking and tweaking to compensate for those inductance/load changes on the lines.
Since the transmitter needs to see a perfect match continuously to prevent “POOF” and maximize the RF injection efficiency, going the simple capacitor/inductor coax idea is well….not a good idea…not unless you can afford replacement finals all the time and don’t mind constant tuning and frustration.
Would it surprise any of you that even the Part 15 TH unit, when connected from its external antenna output jack to one of these real couplers..can send enough signal down the line to cover a 4 block area? Well it can…because I have tried it just for kicks and was quite shocked at how well the signal traveled down the line. But when connecting that same TH unit up to a simple capacitor/inductor coupling scheme, the signal died out less than 2 houses down the street, as well as the incredible amount of hum being fed back into the unit’s RF output. The real coupler units by design null out that annoying hum before it can enter the RF final. A simple cap/inductor scheme cannot. This is why in one of those documents of information, when using the simple coupling scheme, it requires even more RF power to inject the signal…and that is power wasted as the whole point in CC broadcasting is to provide coverage in a limited area..in this case within a certain distance away from that line.
And since all houses and businesses have utility running right into them, why shove a ton of RF power on the line when all it takes is just enough to overcome the noise floor and provide a clean signal directly to everyone’s power outlet..where radios will be plugged in for power.
It is an effective method for broadcasting and works quite well. Perhaps not as glorifying as sending out a flea signal on a 10 foot stick being picked up a mile out, but what better way to get your signal to your audience than to have it being fed directly into their radio via the power outlet!
For more info just ask…and a friendly howdy to everyone.
RFB
Starting Up
This renewed interest in CC got me tonight analyzing the entire AM dial from 530 up to 1350, looking for usable channels that have at least two empty channels on each side, and I have made a list of 13 frequencies!
660 and 720 are the two lowest, but 660 is right next to WSM 650 from Nashville, an amazingly strong 50kW signal. So maybe 660 is too close to the home of The Grand Ole Opry. Come to think of it, I think 720 is WGN Chicago, so maybe we’ll need to default up to 950.
Next will be choosing a transmitter, or building one from one of the diagrams available here in the library (at part15.us).
Probably the Radio Systems coupler because hand making one might be too ambitious and LPB is missing in action.
CC Couplers
Quite often you can find a coupler over on ebay and other auction sites. I recently grabbed a LPB-5 and TCU-30 coupler off ebay and since I already have 3 couplers, one in use, I am going to build one based on the LPB TCU 30 coupler. I also was given a Radio Systems transmitter and coupler from a local church, which the RS coupler has an extra set of inductors which just basically extends the induction selection range a bit from the LPB’s.
Any one of the transmitters within the library (2 watt and above) will work. The key is the coupling and configuration onto the power lines or neutral. As I pointed out, even the neutral line changes inductance throughout the day and night due to load changes. Therefore what is needed is a coupler that isolates the transmitter output from that inductance variance while at the same time injecting the signal at maximum efficiency.
100mW through a proper coupler will surprise you. I have a TH 5.0 unit and I got board one night and decided to hook it up to my main TCU-30 coupler from the TH units external antenna port.
How did Gomer Pyle put it….”SURPRISE SURPRISE SURPRISE!!”
I was surprised at how well that flea signal traveled down the line. Then I wanted to see how well it would work through a basic coupling scheme such as that noted in Ernie Wilson’s document….well that technique was less than surprising…more like a huge disappointment. But I have a project underway on the bench right now working with a basic coupling system to improve it..perhaps even create this thing specifically for 100mW transmitters such as the TH. Maybe build one to put on the market so Part 15 AM stations have an inexpensive way to extend their coverage by the use of TH units and a coupler you simply plug into a wall socket.
So far with the project I have found the following. Sure enough, what the problem was with the simple coupling scheme is the fact that it cannot provide proper load matching for starters, nor can it inject the RF onto the line at maximum efficiency…not to mention the serious lack of AC hum neutralization. Much of the RF energy was being absorbed by the inductor and radiating from that instead of being injected onto the line. Even my LPB transmitters did not like that simple coupler scheme. It took 10 watts through a simple coupler to equal the coupling effectiveness of a real coupler like that of the TCU-30 with 1 watt. So my project at hand is a daunting task to say the least..but nonetheless a real challenge..and I LOVE a challenge!
So the main element in a CC system is not RF power, it is not what kind of transmitter, it is the coupling technique and coupling unit itself that becomes the heart of the entire system.
Think of that coupler unit like that of a loading coil and ground system for a 3m stick. If that loading coil and ground system is not built properly to maximize efficiency of the 3m stick..well we all know how short of a distance that rock gets thrown with that.
Indeed Carl…get in touch and we will see what is what.
(edited to add..)
Most CC stations do use the lower portion of the MW band for two reasons. One being that there are more open channels at the low end of the MW band than anywhere else. Second is that the field strength measurement distance increases a lot when operating on the low end. The formula for figuring distance from the line is very easy…
157,000 divided by frequency equals distance in feet from the line for 15uV/m. So lets say you want to operate on 630Khz…
157,000/630=249.2 feet. That means that at 249 feet distance from a wire, hot or neutral or leaky coax, the signal must not exceed 15uV beyond that 249 feet. In most urban areas and even in tiny tot towns, it is quite difficult to find power lines separated by more than 200 feet…and in some cases..much much closer…such as that found in my area where the residential blocks are quite small and clustered together including the power grids. Lucky me eh! 😉
249 feet might sound discouraging to those who are more familiar with intentional radiator systems. Always remember that in CC, it is not distance off the wire we want, it is distance DOWN the line that we want because that line runs into everyone’s home and business. So it really does not matter if we hit 15uV at 249 feet. If our signal is getting down the line and right into the listener’s radio via the power socket…goal is achieved. The 249 feet part will be useful for those taking an evening stroll around the block listening to a pocket radio.
The biggest advantage of CC is that it does not rely on through the air radiated signals to be picked up unlike how the 15.209 does. Through the air radiated signal at 100mW tends to have a hard time getting through the walls of homes and surrounding environment such as trees and such. CC systems do not have this issue at all. That is what makes it a very viable alternative to intentional radiator. I believe it to be not just a great alternative, but also an excellent way to extend a station’s coverage without having to mount 3m sticks every 4 blocks and the expense of such a setup. TH units are cheap and can be found all the time on auction sites…makes a perfect way to expand your station’s coverage..all that is needed is a good coupler and audio to the TH. Imagine how far you can extend your station’s coverage with 5 TH units and the cost of those versus the price tag of 5 700 dollar transmitters designed to radiate off a CB whip!
RFB
Hi RFB!
Great stuff you have there!
My LPB 6 watt CC transmitter (RC-6A? I think
that’s the model number.)
is being repaired by a friend in
another state, My plan is to put it on 550 Khz
because that is clear here. But my friend is very
busy and I might not get it back for a while.
In the meantime, I will be glad to see any info that
you have. However, because of my poor vision,
I probably could never go to the incredible lengths
that you have gone to, as shown on Carl’s website.
Still, I like reading your CC information a lot.
Best Wishes,
Bruce, Dog Radio Studio 2 (Ex. MICRO1690/1700)
Track Switching
There will be a lot more about Carrier Current on The Low Power Hour Programs No. 13 and 14, right now in production.
And now back to this forum.
Hot Off the Press
Low Power Hour No. 13 is ready and is all about carrier current.
Download at
http://www.kdxradio.com/lph.html
Listen on KDX5 at
http://www.kdxradio.com/demand.html
I Just Remembered An “Almost Carrier Current” Setup
I loaded my Panaxis AM-100 (long ago) into
an AM BCB DX loop by cutting a loop wire
and connecting the transmitter to it. It was
basically an LC across the transmitter output.
Then I took a long extension cord and wrapped
it around the loop many times. (I don’t remember
how many.) Then I plugged the extension cord
into the wall and plugged the Panaxis AC cord
into the extension cord. I tuned for max on 750 kHz,
which was my chosen frequency.
The signal sure got around the house well. Real well.
There was no direct connection to the AC line. I’m
sure it didn’t go down the outside power line very far.
Best Wishes, Bruce, Dog Radio Studio 2
Inductance coupling
Makes me very happy some are finding the information useful and helpful in planning a CC system. There is a good portion of information on the web, but what that information does not focus on is the fact that every installation will have its own quirks and special “fixes” to overcome those quirks, though some of the information mentions the differences.
Your experiment with the Panaxis AM-100 unit and a loop load wrapped with an extension cord is basically the same thing that is found inside an LPB or Radio Systems coupler units….except they are using ferrite core torroid transformers for the inductive coupling rather than a large loop wrapped with a wire..but it is the exact same concept and does work well. Your signal probably got down the line a little bit, perhaps a few houses or more because not only were you inductively coupling to the power grid hots and neutral within that extension cord, the signal on the hots would end at the nearest drop down transformer on the pole, but could have continued on down the line via the neutral line.
At 100mW, through a proper coupler, the signal could cover a couple blocks or more..as I have tested this with a TH 5.0 unit and an LPB TCU-30 coupler.
Your home made extension cord/loop coupler provided you with a good inductive coupling for the signal as well as provided you with isolation from the voltages on that extension cord. Efficiency of the transfer of the RF energy was probably not at its best, but well enough to put the signal where you wanted it…which is the whole idea of CC to begin with…putting the signal right at the listener’s radio as if our transmitter were sitting next to that radio.
The LPB RC-6 series were excellent transmitters. I have seen a few good ones recently over on ebay. One in particular looked like the thing just came out of the factory! It was very clean, inside and out.
They are a real treat to work on and a fun restoration project if you find one that needs some TLC.
Any more CC experimenting stories out there?
RFB
Hi RFB
Thanks for the feedback on my extension
cord coupler.
I was desperate to get the Panaxis transmitter
to be heard around the house. I did not
have the knowledge at that time to make
a working Part 15 3 meter stick with tuning
coil and did not want to string wires all over
the house just to get a 750 kHz signal into
a few rooms. I wish I still had that transmitter and could repeat the experiment.
The nice thing about it was I knew it was
completely safe.
As for my 6 watt LPB transmitter, my friend
in New Jersey will get to it when he can.
I don’t really care how long it takes,
because he is a great guy, a real RF expert,
and he doesn’t want any money from me to
do the job.
I suppose when the LPB rig comes back, I
could make a 10 dB RF attenuator, so the
output would be about 600 mW. Then I could
repeat the experiment. If I did it correctly,
the transmitter would be seeing mostly a
resistive load, so the final RF stage
would be happy.
HMMMMM.
Well, someday.
Best Wishes,
Bruce, Dog Radio Studio 2
Power Cord CC
Indeed…let us know how the experiment goes with the LPB unit. They were designed specifically for CC and perhaps you could set up a CC system with an extension cord/variable load attenuator for the coupling system full time. Then go around and ask neighbors if they are able to pick it up.
Chances are quite good that the father away neighbors will pick it up quite clear vs the 3m setup. That way you can use both..the 3m setup for OTA reception, and the CC system for the fringe reception areas to receive the station indoors where the 3m setup can’t quite do the job.
Or do what I do. The CC system is the primary medium for my AM station and the 3m setup is the emergency backup or maintenance fall back system so the station is still on the air.
Wish I still had my old RC-6A unit. But it was victim to an unfortunate accident when my brother…not sure if he was a bit tipsy or what, but when parking his car in the driveway…he accelerated instead of using the brake and SMASH…right into the wall of the house which just so happened to be where my room was and the table which sat the RC-6A unit and a few other pieces of gear. The impact was just enough to bump the table and knock everything over. The cabinet was bent out of whack and the oscillator PC board was cracked and a few pieces broken away, all the tubes were busted, and the thing was just a complete loss. 🙁
But the neat thing is that my brother helped me purchase a brand new LPB 2-20!! I still have that unit today and is the primary CC transmitter on the air now..sporting the C-CUFF C-QUAM for the exciter.
Look forward to hearing how your CC extension cord experiment goes with the RC-6A!
RFB
Hi RFB
I wrote you and the other guys a
gigantic reply this Monday afternoon.
Somehow it just vanished.
It was probably my error.
I’ll have it back in here as
soon as I can.
Best Wishes,
Bruce, Dog Radio Studio 2
In the Meantime
While we’re waiting for Bruce MICRO 1690/1700 Dog Radio Studio 2 to re-say his message, I will report having attempted to find out how to order the Radio Systems CP-15 Coupler so I would be closer to Carrier Current Operation, BUT….
The radio systems website is poorly designed. It took all day just to locate the CP-15, and then there was no whatsoever mention of cost. Holy trial and error, they make it super hard to order their products.
But I will try again, once I go through therapy.
Missing Post
I look forward to reading it Bruce!
RFB
Pieces of Missing Post
First of all, the mention of the
price of that coupler you guys just
mentioned, Carl and RFB, had me choking
too, and I haven’t even had breakfast
yet. My cooking could make anybody choke!
I was really on a roll with that post
yesterday. Here are some of the things
that I said.
I bought my LPB RC6A sometime in the early
eighties. Shortly after that, my great
friend who lived nearby bought an LPB that
ran 25 watts (maybe it was 20, I’m not sure.)
Both of the transmitters were old vacuum tube types.
Both units had crystals for 640 kHz. At that time
640 was clear at night and during the day, for
that matter. The only station in the U.S. on
640 was KFI in L.A., CA. There was also a Cuban
on 640 at night.
We didn’t know how to use these transmitters. We
didn’t know how to build matching/attenuating
circuits for over the air operation. We did not
know anything about CC line couplers.
Sometime shortly after that
my friend sold his LPB to a broadcast station. I
believe it might have been for low power presunrise
authorization. We had a station in town that was
on 1550, 1000 watts day, but from 6:AM until sunrise
in the winter (or whatever) – it ran 2 1/2 watts. I
have not heard of any other AM BC station having
such a low wattage for that, but I think there mush
be a few others around. I’m not sure if he sold it
to that particular station, but I think the low
power PSA on that 1550 daytimer is a fun piece of
trivia.
As for the RC6-A operation,
I did try rigging up wires in my apartment, such as
a big loop, with a 50 ohm load on the end. I thought
that would get the signal around the apartment, but
it didn’t work very well. I will say, the transmitter
sounded great! The audio was wonderful!
It seems like about a year later, the FCC started breaking
up a lot of the clear channels. Suddenly 640 had lots
of stations on at night, but even worse, a 50,000 watt
station appeared on 640 from Westfield, MA, about 30 miles to
the north of me. So my 640 kHz crystal was now useless.
In all of these years, in spite of the fact that I
have not been able to use the transmitter, I consider
it to be a wonderful piece of broadcast history, and
now I may have a chance to actually use it in the
future. My friend in New Jersey is a brilliant RF
man, especially with vacuum tubes. So he said he
would fix up the RC6-A for me and put it on 550 kHz.
550 is clear here in West Hartford. Those crystals
below 1 MHz are really expensive. But my friend said
that he could get a cheap 1650 rock and build a divide
circuit to get it to 550. 620 kHz is even better, but
beggars can’t be choosers. I am giving him all of the
time he needs to get this thing going. Hopefully, I’ll
have it in less than 6 months. There is so much going on
here in my family and I have so many radio projects on
the table, that time is not really a big deal. I just
hope he really does get to it! If he doesn’t get to it,
I won’t be upset with him, because he’s a great guy.
I’ll just take it back and try to do the work on it my self.
If he can just recap it, I can get new tubes and put it
on 1020 kHz. That channel is clear during the day and
the crystal for it is not that expensive. I think
AF4K’s website has rocks for that channel. I know 1020
isn’t as good as the lower channels, but at least it would
be on the air.
So, we’ll see. I had one funny story about AM DXing,
and that was our quest to receive KFI in Los Angeles, CA
(SP?). In the late seventies, four of us in town, all
serious AM DXers, were trying to hear KFI on 640 here
in Connecticut. All of the experienced AM DXers said that
KFI was the best shot to hear the west coast in
Connecticut. There was only one snag. There was a
pesky Cuban station that ran all night long and was
in the way. So the trick was to listen around
sunrise. When the path to the Cuban station started
to break down, then KFI would start to fade up. You
would be able to hear it for a few minutes until
the sun was higher in the local sky. My three friends
were all able to do it. But I never got KFI. I
tried and tried. I don’t know how many times but it
was a lot. I had a Hammarlund HQ-140X, a receiver
that was very much up to the job. I tried wire antennas and
loops but to no avail. Oh well. I eventually heard
2 California stations on 1640 and 1650 when the expanded
“X band” started up. But it wasn’t the same.
It sure was fun, though.
Best Wishes,
Bruce, Dog Radio Studio 2
Pieces of Missing Post
First of all, the mention of the
price of that coupler you guys just
mentioned, Carl and RFB, had me choking
too, and I haven’t even had breakfast
yet. My cooking could make anybody choke!
I was really on a roll with that post
yesterday. Here are some of the things
that I said.
I bought my LPB RC6A sometime in the early
eighties. Shortly after that, my great
friend who lived nearby bought an LPB that
ran 25 watts (maybe it was 20, I’m not sure.)
Both of the transmitters were old vacuum tube types.
Both units had crystals for 640 kHz. At that time
640 was clear at night and during the day, for
that matter. The only station in the U.S. on
640 was KFI in L.A., CA. There was also a Cuban
on 640 at night.
We didn’t know how to use these transmitters. We
didn’t know how to build matching/attenuating
circuits for over the air operation. We did not
know anything about CC line couplers.
Sometime shortly after that
my friend sold his LPB to a broadcast station. I
believe it might have been for low power presunrise
authorization. We had a station in town that was
on 1550, 1000 watts day, but from 6:AM until sunrise
in the winter (or whatever) – it ran 2 1/2 watts. I
have not heard of any other AM BC station having
such a low wattage for that, but I think there mush
be a few others around. I’m not sure if he sold it
to that particular station, but I think the low
power PSA on that 1550 daytimer is a fun piece of
trivia.
As for the RC6-A operation,
I did try rigging up wires in my apartment, such as
a big loop, with a 50 ohm load on the end. I thought
that would get the signal around the apartment, but
it didn’t work very well. I will say, the transmitter
sounded great! The audio was wonderful!
It seems like about a year later, the FCC started breaking
up a lot of the clear channels. Suddenly 640 had lots
of stations on at night, but even worse, a 50,000 watt
station appeared on 640 from Westfield, MA, about 30 miles to
the north of me. So my 640 kHz crystal was now useless.
In all of these years, in spite of the fact that I
have not been able to use the transmitter, I consider
it to be a wonderful piece of broadcast history, and
now I may have a chance to actually use it in the
future. My friend in New Jersey is a brilliant RF
man, especially with vacuum tubes. So he said he
would fix up the RC6-A for me and put it on 550 kHz.
550 is clear here in West Hartford. Those crystals
below 1 MHz are really expensive. But my friend said
that he could get a cheap 1650 rock and build a divide
circuit to get it to 550. 620 kHz is even better, but
beggars can’t be choosers. I am giving him all of the
time he needs to get this thing going. Hopefully, I’ll
have it in less than 6 months. There is so much going on
here in my family and I have so many radio projects on
the table, that time is not really a big deal. I just
hope he really does get to it! If he doesn’t get to it,
I won’t be upset with him, because he’s a great guy.
I’ll just take it back and try to do the work on it my self.
If he can just recap it, I can get new tubes and put it
on 1020 kHz. That channel is clear during the day and
the crystal for it is not that expensive. I think
AF4K’s website has rocks for that channel. I know 1020
isn’t as good as the lower channels, but at least it would
be on the air.
So, we’ll see. I had one funny story about AM DXing,
and that was our quest to receive KFI in Los Angeles, CA
(SP?). In the late seventies, four of us in town, all
serious AM DXers, were trying to hear KFI on 640 here
in Connecticut. All of the experienced AM DXers said that
KFI was the best shot to hear the west coast in
Connecticut. There was only one snag. There was a
pesky Cuban station that ran all night long and was
in the way. So the trick was to listen around
sunrise. When the path to the Cuban station started
to break down, then KFI would start to fade up. You
would be able to hear it for a few minutes until
the sun was higher in the local sky. My three friends
were all able to do it. But I never got KFI. I
tried and tried. I don’t know how many times but it
was a lot. I had a Hammarlund HQ-140X, a receiver
that was very much up to the job. I tried wire antennas and
loops but to no avail. Oh well. I eventually heard
2 California stations on 1640 and 1650 when the expanded
“X band” started up. But it wasn’t the same.
It sure was fun, though.
Best Wishes,
Bruce, Dog Radio Studio 2
OOOPS
Looks like my last post came up twice.
Sorry about that.
Bruce, Dog Radio Studio 2
I just remembered something else.
RFB,, I’m sorry about how you
lost your RC-6A. Not to mention
the wall in your room.
My grandfather smashed into his
garage door once, but that’s minor
compared to your experience.
I think it’s really great that your
brother helped get you a 20 watt unit,
though.
If I can think of anything else from that
other post I will add it.
Best Wishes,
Bruce, Dog Radio Studio 2
Two Small Notes
The mention of 640kHz reminds me again that WSM is at 650kHz, and I would like to run carrier-current on 660kHz, so I think I’ll do as someone suggested, and use it during the daytime, then switch up to either 950 or 960kHz for nighttime.
The price of the CP-15 coupler is not good news, but it is something I wanted to know, so here is the plan I have for dealing with the situation: for the next week I am going to spend time grumbling and being short-tempered, then I will order one and be very excited about it.
A carrier-current coupler is the kind of thing the survivors in a family would have no idea what to do with. They wouldn’t know if it was junk or whether they should put it on e-bay, and I’m not going to tell them. It will be fun to sit in heaven and watch them figure out what to do.
New or Used?
Might want to hang on for a bit before placing that 495 dollar order. These LPB couplers pop up on ebay often, usually with a transmitter to boot. The most recent was an LPB AM-5 and TCU-30 coupler, which I got both for 144 bucks.
And the units look as if they just come from the factory. The previous owner used them for experimental broadcasting indoors. I gather perhaps using them in a flea market setting or just around the house to get audio from one end of the house to the other. In any case..as I pointed out on the show..always take a good look at the photographs of the unit/s and the seller’s rating. Ask questions, and pay close attention to the answers and how they are worded. It can save you a ton of frustration..as well as risk.
RFB
Loss of RC-6A
Great story Bruce! I hope your friend gets that RC-6A up and running soon! Fixing it up so you can select what frequency to operate on is excellent, and can be done with either the tube units or solid state units.
When my brother rammed his 72 camaro into the wall, I was not at home at the time and the station was off the air for that day. The funny part is when I did get home, he was sitting on the couch with this long sad look on his face..as if he just lost his girlfriend or something, which I thought that was the reason for the sad look. But then he explained what happened and held up a piece of the RC-6A’s oscillator board..I knew right away that the unit was a total loss. I was not angry at him, just relieved that he was not hurt…but boy was his camaro injured extensively! Not to mention the wall in my room! We had fun though, rebuilding the damaged wall and working on his smashed front end of his car. In the end I think it brought us closer as brothers than we had ever been before. That was the most delightful thing to come out of it all.
RFB
Taking Advice
RFB is an influential person, as now he’s got me heading over to e-bay for the first time ever to see what it’s like over there. I’ll come back with a report on my “first impression.”
Impressions
Trust me when I say that e-bay was somewhat intimidating to me at first. Was not sure I could play along and get the hang of the bidding processes. But after a couple of successful bids, it became easy to work with and easy to recognize the honest sellers and not so honest.
Take your time with the new approach of CC for your station. While awaiting a listing for a coupler, you can become familiar with the system and have a head start on the game when you do get a coupler or combination coupler and transmitter and add that system to your station.
And of course..I am around to assist in any way I can for those who need it. I don’t mind passing on information to others wanting to learn about CC. Knowledge shared is knowledge gained for all.
RFB
Hi, I’m Back
The only daunting moment was trying to find the category… but it turns out to be “Commercial Broadcast.”
Wow there are a lot of items to scroll, and some of them look very unique, like a McMartin Vintage Audio Console for only $199. Somebody would love to add that to their station.
All right. We’ll hang around over there every few days and watch what happens.
Many thanks, RF and all the generous contributors who share their knowledge and experience. It’s the best of social.
Technical Roadblock
The “technical roadblock” I am asking about is the envisioned carrier current operation on 660kHz daytime and 960kHz nights. How much equipment will it take to do that and how are the two systems merged?
660 day, 960 night
Very simple. One transmitter capable of selective frequency of operation…and one coupler.
At the appropriate time, simply advise the audience the station is switching over the other frequency….sign off….change frequency…fire up again, re-tune coupler, switch to operate and your done!
RFB
Radio System CP-15 coupler
Last time I checked, which was aprox 1 year ago, the going price for one was $495.00.
Might want to consider some considerable therapy once grasping the price of that thing!! I about choked on it too!
RFB
Short Report On My RC6-A
It turns out my friend in New Jersey HAS
been working on the RC6-A carrier current
transmitter.
I can’t stay on too long, but I’ll relay a
few things.
He got new (probably N.O.S.) 6AL11 tubes.
He got a schematic for the 25 watt LPB,
which he said is very close to the 6 watt
version. He is going to recap it, and
he talked about changing resistors that
have gone out of tolerance because they
are old. He marveled at the beautiful
modulation transformer.
So it’s in the works. I told him if he
didn’t have time to build a freq divider to get
it on 550 or 620 kHz, that I could get an
AF4K crystal for 1020 kHz for $14.00. He
said he wanted to figure out how to get it
on the two lower channels, and that he wants
to do it.
I am fortunate to have such a good friend, and
such an RF expert. He is SO GOOD, that in
1975, he built a tube 10 watt FM exciter from
scratch! It was the kind that had crystals
way down in the 1 MHz range, which were eventually
multiplied up to the FM band. He only had a
partial schematic, so he had to calculate a real
lot of the parts values himself! It worked
perfectly, and it was the first time he had done
any VHF construction of any kind! He was mainly
an MF/HF guy. For some reason, I can’t remember
if the real exciter schematic that he copied was
RCA, or G.E, or what, but we found out later that
there was a real 10 watt exciter of the exact same
kind in a high school FM station in Hartford.
I have more comments for you guys, but I have to go.
Be back soon.
Best Wishes,
Bruce, Dog Radio Studio 2
To RFB and Carl:
First of all, RFB, I think I said it before, but
the story of how you got the LPB 20 watt
transmitter after the 6 watt rig got hit
by the 72 Camaro is an amazing story.
The other question is, I know you transmit
C-Quam stereo. I wondered what you use
to receive stereo.
And to Carl, I think you will have fun with this
CC thing. I would get it going on the daytime
channel first, and then when you are happy
with that you can add the night service.
AM Stereo Receiver
“The other question is, I know you transmit
C-Quam stereo. I wondered what you use
to receive stereo.”
I have 4 units that are capable of AM Stereo reception.
The first, which is the main studio monitor receiver is a Sony ST-JX220A. The second receiver, which I mostly use for scanning the AM band since it has manual tuning is a Radio Shack “Realistic” TM-152.
The third unit, which is my prized possession is a Sony SRF-42 “walkman” FM Stereo/AM Stereo.
The 4th unit is also a “walkman” variant and Sony’s first model series of the “walkman” type portable radios capable of AM Stereo reception. It is the Sony SRF-A1.
RFB
To Carl and RFB.
Carl, I was very excited when I tried carrier
current with a real commercial coupler and
the LPB RC-6A. This was a different experience
from the Panaxis AM-100 and that homemade
improvised coupler.
The LPB and the commercial coupler experiment
didn’t work because the LPB transmitter was
broken. When I realized that, I set it aside. Sometime
after that, I had to give the coupler back to the
RF engineer who had lent it to me. So now the
LPB is being worked on, as I mentioned, and
we’ll see what eventually happens. I had wired
the system for neutral injection, and because it
was a new experience, I was very excited about it.
Carl, I think that you won’t really get a feel for
what frequency to use until you try it. As RFB has
said, there are tons of variables. You could make
a coupler like I did just for fun if you wanted to.
RFB and I have theorized that it probably won’t
travel much distance, but it’s safe, inexpensive
and fun. You could drive it with a 100 mW transmitter
– again, there are lots of variables. It’s just a fun
thing that’s all. It probably wouldn’t go very far,
but it would be an interesting experiment.
I can give you the exact details if you want while
you are waiting to build a REAL carrier current
system. But like I said before, it’s just a big homemade
AM BCB loop. I cut a wire on the outside and put
one wire end on the transmitter ground and one
wire end on RF out. Then I wrapped an extension
cord around the outside of the loop five or six times
and tuned the whole thing for max RF. The transmitter
was plugged into the extension cord, and the extension
cord was plugged into the wall. No direct connection to
the AC line. It worked with the Panaxis rig. But, I guess there is
no guarantee that it would work with some other transmitter.
Boy am I long winded.
Now to you, RFB. I am very impressed with your collection
of AM stereo receiving equipment for C-Quam. I remember
the Radio Shack stereo tuner and the Sony SRF-A1.
I was given a damaged but working Sony SRF-A100. I’m
sure you know what I am talking about.
The radio works great, but the whole front was dented and
scratched up beyond disbelief. I took the whole front grill off.
The tuning guide in the middle is mostly intact. I am actually
cutting up a speaker grill from another junk radio to glue onto
the front of the A100. It is critical that it fits just right and
looks good or the project will be pointless. The radio works
great, and even though it may not look exactly like the
original, it should look pretty good. The tuning guide number
section in the middle is scratched up, but it is not too obvious.
I know some people who have SRF-A100s that don’t work anymore.
It’s great that this one still works.
There are 3 AM stations in Connecticut that are still transmitting
C-Quam stereo. One of them is close enough for me to hear
the stereo, and boy, does it sound good. It’s about 30 miles
away, and is a 1 kW daytimer on 1220 kHz. All 3 stations are
owned by the same group. Maybe someone in that broadcast
company (small, independently owned) just sees the beauty in
the system, and wants to keep C-Quam on the air.
I remember listening to AM stereo in the 1980s, and it sounded
great. it’s a real shame that it didn’t work out. The station could
be 500 miles away, and the stereo would still sound fine.
You must get tremendous satisfaction from transmitting and
receiving it. That must be really great! There are AM stereo
web pages out there from people who love it just as much
as we do, and I guess Sony still makes a little AM Stereo
receiver, known as the SRF-A300. I don’t know how good
it is, though. And you have to buy it direct from Japan.
Well, that’s enough for now.
Best Wishes,
Bruce, Dog Radio Studio 2
Lack of AM Stereo interest in the 80’s
It is sad that AM Stereo did not get a good foothold within the US back in the 80’s. While the US and the FCC were piddling around wasting time, other countries were driving full speed ahead with AM Stereo.
Now we have this IBOC, which I call “IBLAH”. It is worthless, generates a heck of a lot of band splatter above and below the station channel, and in my opinion, does not even come close to the sound quality of C-QUAM, even though IBOC is digital.
In fact I have listened to stations running IBOC and I hear more audio drop outs and skips like that of a skipping CD or internet congestion when listening or viewing media across the web.
C-QUAM produces a very clean, very warm “milky” sound. And it can fool even the most critique audio buff. I had demonstrated AM Stereo with the SRF-42 tuned to my station for an audio buff recently. They could not believe that it was AM radio they were hearing in full rich stereo sound.
99 percent of the time my studio monitor is monitoring the AM station instead of the FM station. It just sounds better, more “punch” and more loudness than FM IMO.
You know what is so ironic about the lack of AM Stereo interest in the US? It is the fact that during the FCC’s position of “Let the markets decide” for the standard, there was very little to NO advertising or public education campaign for AM Stereo. Well duh….how can the market be the determining factor for selecting the AM Stereo encoding standard when both the radio receiver manufacturing end and the broadcasting stations sat back and did nothing to really promote it or even introduce it?!!
Even though there were a few stations running AM stereo during that time…a few is not enough to properly introduce the system to the radio listening audience. It was like they put a seed into the ground and never watered it, expecting it to grow on its own and produce big results. PFFT!
Other countries were actively promoting it through the radio receiver manufacturers with billboard campaigns, advertising, mailers and even one particular maker…Sony….made a run of their SRF-A1 units with Coca-Cola decorated cases and were giving them away! There was one such SRF-A1 with the Coca-Cola case on ebay a few months ago. The final winning bid was over 300 bucks!!
Now that HD radios are out there, most of those have the C-QUAM decoding capability.
RFB
Yikes – I missed your last sentence!!!
This is an edit rewrite. I can’t
believe I missed your last sentence!
I have erased most of what I just
wrote.
Because I heard from another source that
my Radiosophy AM/FM “HD” radio, which was
given to me by my brother, could get AM C-Quam.
I didn’t believe it. But since you say
it’s true, I’m going to haul the thing
up from the cellar tomorrow and try it.
Yup. I was really upset about the demise
of AM C-Quam stereo in the 1980s.
It could have been great!
Best Wishes,
Bruce, Dog Radio Studio 2
P.S. I looked on YouTube a
while back, and some people have
posted recordings of C-Quam AM stereo broadcasts
that they audio taped decades ago.
Some of the recordings sound quite good.
Some HD radios
Here are a few good HD radios.
http://www.amazon.com/HD-Radios-recommended-by-WXXI/lm/R3DQOQXB74LHXX
I recommend the Sangean HDT-1 unit. It is a component tuner and has the C-QUAM decoding capability on AM. I have one in our living room connected to our home theater system so I can monitor the AM station in between watching DVD movies.
RFB
3rd dud
Another duplicate post gone dud.
RFB
Already Having Fun Before Doing It
This new incentive to plan a carrier current station is already major fun and yet so far it’s been nothing but talk and planning.
To capture the feeling I grabbed a JPEG showing the CP-15 coupler and posted it on the Low Power Hour Program 13 slot as part of the RFBurns visit, since he (you) did mention it. That way anyone who daydreams about it can go there and see the real thing. Come to think of it I should add a link to the specs page. Will do.
Today I visually inspected my power line which looks the same as it did yesterday, except that today I am viewing it in a new way. There it is, waiting for input.
Last night I cursed at cable television while hitting the OFF command, and went straight to an AM radio where I tested nighttime frequencies for carrier current. I had previously checked out those frequencies, in the 900kHz range, when first searching a Part 15 channel. I found my old paperwork, and here are some details:
A local 500Watt station sends gospel songs at 920kHz, so we skip the next three channels and find that 960kHz has me surrounded by three stations that have come in on rare occasion, KMA, Shenandoah, Iowa, 5kW; KZIM, Cape Girardeau, Missouri, 5kW; and WSBT, South Bend, Indiana, 5kW. But 970kHz would also be good.
At 970kHz we have WMAY, Springfield, Illinois, 1kW day & 500W nite; KNEA, Jonesboro, Arkansas, 1kW day & 41W nite; and KJLT, North Platte, Nebraska, 5kW day & 55W nite, so maybe 970 is the better channel.
Skip the next three, and the other station near here is 1010kHz day, 50kW, but their nighttime is very weak, I can’t usually hear it.
REVIEW QUESTION….. maybe 970kHz should be the full time CC channel… I was planning on 660kHz so we could get as low as possible, but maybe….
And I would love to grab 570kHz because it is very clear, but there is only one guard channel on either side. Tell me again. Is that the wrong way to think?
Am I going mad or is this what it’s like to have fun.
Fun in the Sun
“Am I going mad or is this what it’s like to have fun.”
Na…you’re not going mad. Your experiencing the fun that quite often gets set aside in this field because of straight jacket attitudes about radio and electronics in general.
It is supposed to be fun! 🙂
RFB
AM Stereo kicks HD in the rear!
AM Stereo kicks HD in the rear! i agree with rfb. AM Stereo is much better then IBOC which creates hashing 3 channels below the frequency. AM Stereo creates better sound and no hashing.
May Not Withstand Ebay
It was well meaning advice that suggested money could be saved by finding a carrier current coupler on ebay. So I visited ebay and had trouble finding the right category, but it turned out to be “Commercial Broadcast.”
But today when I searched “Commercial Broadcast” I saw some beautiful seed-spreaders that are known as “broadcasters” for seeding.
But I hung in there and found “AM Transmitter,” which gave page after page after page of crystals. Now it’s nighttime.
I have patience, but time goes by and after several days patience no longer counts.
That’s why I might abruptly dig for pocket lint and try to buy a full-priced coupler.
Carrier current is an experience that might make life really cool.
Patience Luke…
I waited quite a while but did finally get one from Ebay. The LPB TCU-30.
The price was $99, not a bad deal.
Played with it a bit using my Radio Systems Phase II 20 watt transmitter.
I could cover everyone on the same utility transformer feeding the signal into the hot side of the line and ground. Unfortunately that was only about 8 houses.
Lucky Hot Side Results
“I could cover everyone on the same utility transformer feeding the signal into the hot side of the line and ground. Unfortunately that was only about 8 houses.”
That’s not bad at all for coupling to the hot side! Most cases with a CC system coupled to the hot sides in a typical neighborhood are lucky to even hit 3 houses…maybe 4 before hitting that road block transformer.
Have you tried neutral coupling? With results like that on the hot side, you might be surprised at how good it may work on the neutral side! Worth a try at least.
RFB
Looking For Way To Go
At 10 PM I sat listening to 970 kHz, and it was wonderfully clear with no stations coming in. It will be the carrier current channel for KDX and I think there’s already a path into the hot side of the 220 VAC which is set up and ready to go.
Down where the drier was is a like-new 220 VAC 3-angled-prong outlet. I will plug the CP-15 coupler right in there and avoid messing with the electrical breaker box.
Also plan to test neutral-loading for comparison.
There is a 5-Watt transmitter design in one of the Carrier Current publications in the library on this website, and I think I’ll build that.
RFB, is anything new with the coupler you are designing?
EDITOR BACK FOR MORE: Do you know about the Long Wave Club of America?
http://www.lwca.org/