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Tracking down power line noise
On Jul 13, 5:44*am, Bill wrote:
... I used to swim in it and in 1954 I could watch the steam engines hauling the daytime commuters to Chicago on the far side of the lake. Times change. Bill Baka Hmmm. Wonder where that rail line could have been. None near Wonder lake now. Perhaps it was McCullom Lake you mentioned - there *is* a rail line near it. 73, Steve, K9DCI |
#2
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Tracking down power line noise
Noskosteve wrote:
On Jul 13, 5:44 am, Bill wrote: ... I used to swim in it and in 1954 I could watch the steam engines hauling the daytime commuters to Chicago on the far side of the lake. Times change. Bill Baka Hmmm. Wonder where that rail line could have been. None near Wonder lake now. Perhaps it was McCullom Lake you mentioned - there *is* a rail line near it. 73, Steve, K9DCI It was McCullom lake, about 8 houses to the right of mine down the road. My grandparents lived about 6 houses to the left, so it was ideal for me as a young child. I once hiked through the corn fields (now condo fields) to downtown McHenry and was about 100 feet from a steamer spinning those huge wheels on startup. That was something I will never forget, just the raw power and mechanical stuff up close. That, to me, was American life. I also got into early morning television DX'ing at about 5:00 A.M. turning the rabbit ears and seeing what I could get. I got Grand Rapids, Mich once and Racine's test pattern once and a few more buried in the snow. At any rate I was hooked on radio and television stuff. Bill Baka |
#3
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Tracking down power line noise
I once had them track down noise when I lived in North Texas, and the source
was insulators with loose hardware about 2 miles away, destroying 40 and 80 for me. Yup, it is all hooked to a huge antenna... -GeorgeC W2DB "Rick" wrote in message ... I have been wrestling with power line noise here for almost a year. Power company hasn't been very successful in locating it so I started a coordinated search on my own. Thinking if I can tell them for certain which poles have the problem they can confirm and maybe fix. The noise is a deafening 20 over 9 on 80 meters which makes DXing on 80 and 160 impossible. The noise can be heard at my QTH as high as 10 and 6 meters but it isn't troublesome on those bands because it can only be heard at about an S7 level when the yagi is pointed at 210 degrees. I thought maybe my means of analysis might be interesting to discuss and maybe others would have other suggestions. There are 7000 volt lines running on a highway past my house. Tracking the source on 80m seems impossible. I made a 2 ft square loop antenna, which has some directivity but the noise level using it seems to not change much as I travel the highway. On 10 meters, using a 4 ft whip on the car, the noise is also hard to localize but seems to increase in the vicinity of 1 mile from home. 6 meters using a whip is similar. I found that if I'm close enough that the 6 meter signal is around S7 I can switch to 2 meters and again peak the noise by driving slowly up and down the road. So using this technique and driving 2 miles in each direction I have managed to find 2 spots, one on the highway and one on a cross road, each about 1.2 miles from the QTH. I then built a 432 MHz 8 element quagi beam which enabled me to pinpoint the offending pole at these two locations. (I have put a LOT of effort into this project !) At this time I am waiting (hoping) for a return call from the power company to verify my dicovery. So my question for the group - Can either of these locations 1.2 miles distant cause such horrendous noise levels on 80 meters? Is it possible that a weaker noise source much closer to me is the culprit or are all of the power line malfunctions detectable on 440 MHz? Rick K2XT |
#4
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Tracking down power line noise
In article , "George Csahanin"
wrote: I once had them track down noise when I lived in North Texas, and the source was insulators with loose hardware about 2 miles away, destroying 40 and 80 for me. Yup, it is all hooked to a huge antenna... -GeorgeC W2DB Hello, and years ago I needed to do some electrically-small antenna tests at one of our NRL field sites. These tests involved the entire 2-30 MHz band so it was always a challenge to find a quiet spot (We were using rack-mounted R-390 receivers in the testbed). In addition to the usual atmospheric noise and radio station interference there was always what appeared to be some local electrical noise that came and went and was worse on some days than others. A.C power to the site was brought in via utility poles to pad-mounted step-down transformers. One of my cowarkers suggested a technique for locating interference that he claimed to have success with in the past: A hand-held sledge hammer is used to whack the utility pole while listening for an associated change in noise on a cheap MW band transistor radio tuned off-station. My cowarker claimed that if a cracked insulator(s) was the perpetrator this technique would confirm it. We tried this technique at the site but with no success. We also drove down the site access road about 1/4 mile with a car AM radio tuned off-station and also got the interference in the vicinity of the utility poles. As a result we never did locate the source. My conclusion was that while the interference was being coupled to the antenna-under-test it may have been generated at a considerable distance from the test site and conducted via the overhead power lines. Sincerely, and 73s from N4GGO, John Wood (Code 5550) e-mail: Naval Research Laboratory 4555 Overlook Avenue, SW Washington, DC 20375-5337 |
#5
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Tracking down power line noise
Hello, and years ago I needed to do some electrically-small antenna tests at one of our NRL field sites. These tests involved the entire 2-30 MHz band so it was always a challenge to find a quiet spot (We were using rack-mounted R-390 receivers in the testbed). In addition to the usual atmospheric noise and radio station interference there was always what appeared to be some local electrical noise that came and went and was worse on some days than others. A.C power to the site was brought in via utility poles to pad-mounted step-down transformers. One of my cowarkers suggested a technique for locating interference that he claimed to have success with in the past: A hand-held sledge hammer is used to whack the utility pole while listening for an associated change in noise on a cheap MW band transistor radio tuned off-station. My cowarker claimed that if a cracked insulator(s) was the perpetrator this technique would confirm it. We tried this technique at the site but with no success. We also drove down the site access road about 1/4 mile with a car AM radio tuned off-station and also got the interference in the vicinity of the utility poles. As a result we never did locate the source. My conclusion was that while the interference was being coupled to the antenna-under-test it may have been generated at a considerable distance from the test site and conducted via the overhead power lines. Sincerely, and 73s from N4GGO, Just in the past few months or more there was a nice article and product written in either CQ or QST magazine. I have just gone through the Index for every issue for the past 4 or 5 months of both magazines and can not find that article.... very frustrating. The article outlined a product ( kit?) for an untrasound receiver and illustrated how the author configured it in order to find power line interference from just the sources you are looking for. It is a much more elegant solution than trying to use radio and usually pinpoints the problem right down to the proper cross-arm on a pole. Wish I could provide more info but I've spent the last half hour looking for this and am apparently over-looking it. ... sigh good luck Ed K7AAT .. |
#6
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Tracking down power line noise
While not the article I was just referring to in my just previously posted comment, there is a good how-to build project in the April 2006 QST on this. Ed K7AAT .. |
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