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Post by Deleted on Jun 30, 2016 19:32:19 GMT
Carrier current is a tremendous form of low power part 15 radio, but the equipment is a different beast from ordinary 100 mW transmitters.
A few strokes of luck on Ebay and I have two LPB transmitters and three couplers, one the Radio Systems type.
The LPB 2-20 was on the air and running for a year or two, then blew a diode in the 15 Volt supply, presumably because of a bad capacitor.
This isn't going to be a rush job, so I have been looking at it in very slow motion.
First thing I spotted was that I removed the two fuses and have no idea where they are.
To purchase the exact fuses I have been spending hours with the Mouser Catalog reviewing how many types and shapes of fuses there are. It took awhile but I now have the proper part numbers for ordering fuses.
Next I made a list of all the electrolytic capacitors in the 15 Volt circuit which is eight.
But then I realized the Bias Circuit, part of the 15 Volt section, does not match the manual, as there must have been a major revision either before or after my transmitter was made, which means the parts are different.
Coming up soon is the other LPB Transmitter, a 5-Watt unit that I have never turned on and don't know its condition. It's built for 1510 kHz, so I will fire it up to see if it's good to go. Anyway, it will eventually be re-tuned for 970 kHz which is my carrier current home.
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Post by Deleted on Jun 30, 2016 22:04:44 GMT
Digging Deeper
This Mouser Catalog is thick like an old fashioned telephone book, and now I'm in the electrolytic section... wow, there are many sizes and designs and electrical values for electrolytics, so I'll be in these pages for at least another day picking part numbers.
If running a radio station wasn't such an intelligent and interesting thing to be doing it would probably be a huge waste of time.
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Post by Deleted on Jul 1, 2016 0:49:15 GMT
Bold Experiment Being Planned
There is a chance the blown diode, marked by its darkened color and scorched pattern on the circuit board, failed because of heat in the transmitter, a well known weakness of this unit when operated in the wrong position, which is what took place.
If I have one of these diodes in the spare parts box I'll install it and see if the transmitter wants to run.
If another diode blows, it will be time to replace the electrolytics and whatever else might be compromised.
There aren't too many carrier current projects going on this summer, this might be the only one.
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Post by thelegacy on Jul 1, 2016 22:37:00 GMT
Are you wiring it to the breaker box or is there a way to use a standard 110 volt outlet socket and do carrier current? Either way this stuff is exciting as we find out how far this could go.
I understand that the Ramsey AM25 can be beefed up to 25 Watts plus and can be made to use carrier current. The audio sounds great with that unit too.
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Post by Deleted on Jul 1, 2016 22:57:09 GMT
Use an LPB Coupler
Luckily KDX has an LPB TCU-30 Coupler to go between the transmitter and powerline.
Using the neutral-loading method has worked best in my original tests... for some reason my system would not match into the more usual 240 VAC circuit.
It is possible to feed a 110 VAC wall plug, but that only transmits on 1/2 of the two branches that distribute from the 240 VAC, which means that some outlets will have no RF signal from the transmitter.
My first hunt for a IN4007 diode has turned up other diodes, but not the one I'm searching for. The search is not over, I have tons of spare parts hidden everywhere.
Having searched through the electrolytic sections and the diode section of the Mouser Electronics catalog it is astounding how many varieties of these parts exist.
At least two guys have said they plan to design their own couplers, but so far this has not happened.
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Post by Deleted on Jul 2, 2016 15:03:19 GMT
Holiday Transmitter Plans
The LPB 2-20 Transmitter is set aside for now pending ordering of parts.
Good time to give the LPB AM-5 a test drive to see if she is sea worthy. See, she, sea... accidental poetry.
The AM-5 is adjustable from 0 - 5 Watts, was manufactured in March 1985, and looks clean and well taken care of.
Since buying it from Ebay I have never turned it on.
It is now connected to the TCU-30 Coupler, but instead of feeding the powerline it has a 3-meter antenna attached.
FACT: This is the same equipment that was also sold as TIS (Traffic Information System) systems, and can be matched into an antenna.
Had to stop the project long enough to set up the programming for KDX... starting with newscasts, leading into the weekly opera broadcast.
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Post by Deleted on Jul 4, 2016 23:20:54 GMT
Moving On
The AM-5 LPB Transmitter is in working order! That is really great news.
Since testing it on Friday I've spent many hours sorting through all the LPB documents I have, all those posted by Jeff Station 8 on the ALPB website, a few sundry websites that have LPB remnants, and the infamous watermarked LPB documents at hobbyshoe-polish(dot)net.
Yes, it's true. A giant HOBBYSHOE-POLISH watermark is printed at an angle right across the vital information of several LPB documents, making them nearly illegible. It's hard to understand, because the web keeper at Hobbyshoe claims he was given permission to post the documents, yet a watermark implies ownership. Would-be-gods act in mysterious ways.
And you know, having been thinking about carrier current for over a week, I now think we should banish all talk of it for reasons of public safety! I mean it. Forget the fact that FCC rules allow it, somebody could get killed messing with AC electricity, and part 15 people are getting to be rare enough as it is... we don't want them having industrial hobby accidents.
Another thing is that a lot of websites talk about carrier current as "ancient history", imparting the notion that it no longer exists.
It's the 4th of July, a carrier current electrical explosion would fit right in.
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Post by bluebucketradio on Nov 15, 2016 0:56:49 GMT
Quote from Carl:
"Another thing is that a lot of websites talk about carrier current as "ancient history", imparting the notion that it no longer exists."
Hardly, carrier current is still in use in many different forms, Broadband over power lines, power line control, wireless wifi links over household power lines.. I think those folks that bash Carrier Current just can't make it work.
My two cents.
Barry of BBR 1620
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Post by Admin on Nov 15, 2016 22:16:41 GMT
I will soon put my CC AM station back on air. I was easily heard 2 miles when in the car.
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Post by thelegacy on Nov 19, 2016 17:21:30 GMT
Damn I wish I had good eyesight or could get someone to wire up one for me. That is the exact range I'm looking for. How good was the signal? That would get me to the Deltaville Market on AM and between here and their there is a strip mall and a Chinese restaurant. So if people knew they'd hear a clear signal they may listen and then I'd not have to worry about those temperature inversions.
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Post by Deleted on Nov 19, 2016 18:39:48 GMT
Written for TheLegacy
Hi Troy.
I learned quite a bit about carrier current during the time when mine was working.
My first idea for you is to contact radio engineers at licensed stations in your area and after that try amateur HAM operators... explain your situation and tell them what you'd like to do and maybe you'll find a guy who will help you wire up a carrier current station.
A lot of my help came from an engineer who maintains full power stations.
But pay attention to this... you may not get the same range as someone else gets.
Carrier current is very much affected by the electric lines it gets fed into, and circumstances vary so much that some people get a lot of distance and some people get very little.
My result was no better whatsoever than I already got with my SSTran AMT5000 with good ground radials, which was about 1,000-feet.
The only way you will know how yours will work is to try it.
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