Hello and my first post to the forum,

I live next to Amtrak who has converted to 25 KV overhead live wires to power their locomotives motors The change from Diesel to electric happened 15 years ago and at first, the lines were silent but now there is horrific arcing which obliterates signals coming in to my ham radio and is often so bad I can not operate at all.

I walked along the track with an AM radio and have found the interference to be apparently coming from multiple locations and is surely being re-radiated along the power line making it difficult to localize the place where the arcing itself is happening. What I need to do is make one of the "big ear" type portable audio amplifiers and utilize a parabolic dish for directivity and to amplify the sound of any arcing so I can identify exactly where the problem is. It would probably be best for me to use headphones with this amplifier and would use my Bose QC-15 noise cancelling set to keep outside sounds out of it & reduce feedback issues.

I read this link http://forum.allaboutcircuits.com/showthread.php?t=76929 which had a link to http://www.rainbowkits.com/kits/instructions/AA1.pdf which looks like it might be worthwhile to go with as all I am needing is the ability to hear arcing.

What I'd like to know is if this project kit would be effective for my needs and if there might be mods to this one to make it better, or perhaps there's a different kit that would be more functional for my needs & is inexpensive.

Happy New Year and thanks for any suggestions.

 

In my limited experience, the circuit below works better than the AA1 amplifier in the link, and it's easy to build.
U1 is an LM386.

What do you plan to do for a paraboloid?

 

What do you plan to do for a paraboloid?

I'm more interested in how he plans to correct the arcing.

 

I'm more interested in how he plans to correct the arcing.

In the "old days" when the FCC had teeth, hams could complain about such things and get action. Now, I don't know. Maybe a more direct approach?

 

In the "old days" when the FCC had teeth, hams could complain about such things and get action. Now, I don't know. Maybe a more direct approach?

That is what I was thinking. If the train is behaving like a giant spark gap transmitter hitting virtually all bands, the owners of the line are responsible for finding and correcting the fault. The FCC used to quite on top of things.

I wonder how many other people in the area are having issues with their wireless phones, bluetooth headsets, etc. intermittently quitting?

Unless he is directly under the line, the problem sounds like it should affect quite a few people and devices.

 

Thanks for the replies.

@ Tracecom: For the parabola I thought I'd try the simple first and use a plastic container that cookies come in at the local supermarket, it has a flat bottom but the sides are rounded. I also thought about trying something like the bottom of an old popcorn popper which has the correct shape & can be found in the thrift shops.

What is there about this circuit that you think is better for my needs?

@ Thatoneguy & Tracecom: That's a good question. I've asked around and found the actual "owner" of the electric lines where I live as different parts of the rail lines are supplied by different entities. There are several issues involved with this arcing problem which for me #1 is removing the interference but for the purposes of getting removal, it's a public safety issue in that with arcing, eventually there will be equipment failure and will that failure be catastrophic and cause damage to life or property, or will it interfere with normal operation of the train or just be a power vampire? If the arc causes significant erosion of metal and/or the arc creates a more conductive path and bypasses the affected insulator what happens then? If the company won't willingly fix it for interference reasons, I'm guessing the FCC would be interested and for safety reasons I expect the PUC will be interested and demand the issue be investigated as to its source.

There aren't many people near the track & their power lines, I am the only one this near for many miles. This house was chosen 40 years ago because it is on a dead end, surrounded by state parks and the train line was diesel. The reason that it's a dead end is because of the train line. The electric was brought in when Amtrak decided on high speed rail and they removed the cross ties and replaced them with concrete ties and welded rails for a smooth quiet ride. Now there is no more clickety clack, just a whoosh when the train goes by. My antennae are 100 feet from the rail line. This house was RFI silent for 35 years until recently when those Amtrak insulators began arcing or the ground connections became corroded. Bad luck for me but this is what I need to locate.

My assumption is the train line does not have the equipment or trained personnel in this area like the electric company has to locate RFI issues with their equipment. When I contact the local utility about interference they come out with a trained tech who finds and fixes it within a couple of days. If I can localize the issue to the offending failure, I think I'd have more leverage to get something done.

it's not when the train goes by that is the problem; as when the "wipers" touch the cable above as the train passes there is a definite arcing as the train goes by but that lasts for maybe 10 seconds and is not as loud as what the arcing causes. This arcing is usually there but not always. At this exact moment it is not there but it comes intermittently and lasts for hours. One time when I was walking next to the line with an AM radio a train went by, the arcing from the wipers lasted for maybe 2 minutes after the train went past. The sound I was hearing was not from the trains wiper, it was from a local arcing that happened when the train passed and persisted till it it stopped. That was an unusual occurrence, usually it's a constant arc or one that arcs 2/3 times/second for hours at a time. The mention of spark gap transmitter is a good one, that's what it sounds like.

That's why I need a good directive listening device so I can hear the arc itself. If you know what it means to have a S2 noise level when the band is open on those days when there are moments of silence, this arcing will easily register S9+20 and then drop back to S2 when it stops.

Ugly...

 

Maybe make a directional antenna for the radio, instead of a directional microphone?

Also, it sounds like it's quite variable, and also intermittent. I wonder what basic causes there could be, for that. Maybe too many and too variable to be helpful in narrowing the search.

 

25Kv, I wonder if it is corona? you can sometimes see it at night as a blue propane like flame. We see it occasionally on a sharp edged fitting in our switchyard.

 

What is there about this circuit that you think is better for my needs?

I built the AA1 circuit on a solderless breadboard and could not get it to work. I asked for help here, and two knowledgeable forum members declared it a poor design. (You can read the thread if you want the details.) However, I still think that I made some assembly error in the AA1, but I couldn't find it.

Having built several circuits with the LM386, I decided to follow the guidelines in the LM386 datasheet and try a circuit with no preamp, but a gain of 200. I built that circuit on a perfboard and it works, but I got interested in some other projects and have not actually used it with the paraboloid (that I built out of paper and duct tape.) So, I can't say definitively that my circuit works as well or better than the AA1. The AA1 kit is fairly cheap, and based on the fact that it has been in the market for quite some time, probably will meet your needs.

FYI, I also ordered a deluxe amplifier kit from N&V magazine, but have not yet assembled it.

With regard to the S9 +20 noise, I know exactly what that means and how frustrating it must be; I have been a licensed amateur for over 40 years.

Good luck. 73.

 

Thanks for the replies.

@ Tracecom: For the parabola I thought I'd try the simple first and use a plastic container that cookies come in at the local supermarket, it has a flat bottom but the sides are rounded. I also thought about trying something like the bottom of an old popcorn popper which has the correct shape & can be found in the thrift shops.\

<snipped>

I don't believe that those will be sufficient. You might need a pretty close approximation to a mathematically-parabolic surface, with a mic at its focal point. Anything else might not be directional-enough. You also need a large-enough sound-gathering surface. I would guess that something in the two-foot diameter range might be sufficient.

There used to be a product called "Big Ear" that was exactly what you want. Now there is one called Big Ears that is way too expensive. But I am confident that most diyers here could make their own, quite easily.

Before making a parabolic dish from scratch, i would try to find an existing one that I could use. How about a small satellite dish that is no longer being used? (I have two of those.) Anyway, here is a link to a google search for "big ear parabolic":

http://www.google.com/#sclient=psy-...375594d9025691&bpcl=40096503&biw=1262&bih=829

And here are a bunch of links to "DIY parabolic microphone":

http://www.google.com/#sclient=psy-...375594d9025691&bpcl=40096503&biw=1262&bih=829

Cheers,

Tom

 

You are not trying to collect sound with your parabolic so I hope its inner surface (the one exposed to the source) is covered with a metallic material. Is it?

 

You are not trying to collect sound with your parabolic so I hope its inner surface (the one exposed to the source) is covered with a metallic material. Is it?

I think the OP is trying to locate the arcing by listening for the sound that it makes when it arcs. He has no trouble receiving the RF signal, but it is too strong to precisely locate the source.

 

I think the OP is trying to locate the arcing by listening for the sound that it makes when it arcs. He has no trouble receiving the RF signal, but it is too strong to precisely locate the source.

I stand corrected. THe OP is trying to hear sound.

I did not read carefully his OP.