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And so the Noise Saga begins: post mortum




 
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Author Topic: And so the Noise Saga begins: post mortum  (Read 4971 times)
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w1vtp
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« on: June 01, 2012, 10:10:24 PM »

Well, finally got around to doing my test that I mentioned in the previous thread.  Meanwhile, a while back I had done w little snooping up and down the band and discovered that the "noise" ran out in the high end of the AM band.  The spectrum analyzer revealed some coherency.  Another clue was that 40 meters was pretty much free of the "noise."

My last conversation with the engineering dept (or whatever, at least it was not the "front desk) was that I was going to turn off everything in the house and see if my new problem went away and that I would get back to him on the results. That's where we left it.

Fast forward to today.  I grabbed my portable radio, turned it on an sure enough at the top of the AM band that "noise" was there.   I started with the shack breaker - no change.  Went down to the main breaker and flipped the breaker and the "noise" went away.  Breaker back on and I proceeded to flip the breakers in turn of and on again until the "noise" went away.  Turns out that a recent addition of a cable TV converter had one of the newer style power supplies a wall wart - that was the culprit.

Lesson learned for me?  This isn't the first time I have been burned by the junk of today's electronics and I should have been prepared to at least suspect this new piece of electronics.  From now on, I think I will be more proactive with checking new equipment I bring into the house.  Another point (and one that had been made here) was not to burn any bridges. I will be more comfortable calling my contact at the power company because I didn't burn any bridges while discussing the problem with him.  I'll be calling him up this coming week.  Meanwhile, I'm becoming more and more interested in some of the tools that will be needed for future detective work in the "noise" front.

Al
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Patrick J. / KD5OEI
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« Reply #1 on: June 01, 2012, 11:04:31 PM »

How about that! It just shows the FCC label is a cop out. these things are free to make noise, not prohibited from it, because the noise has to be annoying enough to warrant an annoying and painstaking investigation - like the one you did.


I have one brick that only makes RFI when it has no load, when the laptop is 'off'. My burglar alarm makes RF noise at CPU frequencies but it's weak, only in the house.

A nasty source of buzzing noise covering 80 through 40 meters here turned out to be the mercury vapor lights. There is a little sensor on top. Apparently these things run hot and one was arcing or buzzing constantly. I didn't realize they got warm in the day time. There is a photoresistor in there that passes current to a bimetallic strip that is heated keeping the contacts open, so these things use power all the time.
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WD5JKO
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« Reply #2 on: June 02, 2012, 08:23:23 AM »

Good detective work Al..

The conversion of transformer based wall-worts to offline switching wall-worts is complete. Now the new stuff will proliferate in our households as we update our stuff. Could be that charger for the new Norelco Lithium Ion battery based shaver, or the battery charger for the kiddies go-kart.

So what can we do? Well if there is no smarts in the wall-wort, then maybe using an older transformer based unit will do. But what if the wall-wort has smarts such as a charger for rechargeable batteries that has a fast charge followed by a trickle charge? Were screwed unless we filter the thing right at the power plug, and put a bead or two on the power cord. Depends if they radiate from the output wire, or if these things conduct the EMI into the power grid. They probably do both.

Its bad enough if we have one in our house. What if the neighbor has one, and then 2...3, up to a dozen?  Huh

Jim
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WD8KDG
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« Reply #3 on: June 02, 2012, 10:06:06 AM »

Good detective work Al..

The conversion of transformer based wall-worts to offline switching wall-worts is complete. Now the new stuff will proliferate in our households as we update our stuff. Could be that charger for the new Norelco Lithium Ion battery based shaver, or the battery charger for the kiddies go-kart.

So what can we do? Well if there is no smarts in the wall-wort, then maybe using an older transformer based unit will do. But what if the wall-wort has smarts such as a charger for rechargeable batteries that has a fast charge followed by a trickle charge? Were screwed unless we filter the thing right at the power plug, and put a bead or two on the power cord. Depends if they radiate from the output wire, or if these things conduct the EMI into the power grid. They probably do both.

Its bad enough if we have one in our house. What if the neighbor has one, and then 2...3, up to a dozen?  Huh

Jim
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Mass complaints to the FCC & Congress should have started years ago, by the amateur radio ranks. Sad

Craig,
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Ham radio is now like the surprise in a box of "Cracker-Jacks". There is a new source of RFI every day.
wd9ive
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« Reply #4 on: June 02, 2012, 11:09:00 AM »

I had a similar issue a couple of years ago, drove me nuts for a week or so. I finally opened every breaker in the main panel and closed them in one at a time while monitoring a battery powered xcvr. Turned out to be a cheap trickle charger type battery tender I had recently purchased. I had it on the lawn tractor out in the barn.
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Sam KS2AM
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« Reply #5 on: June 02, 2012, 11:22:08 AM »

:-)
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« Reply #6 on: June 02, 2012, 11:35:43 AM »

As far as tools go,  a 4-5 element 2 meter yagi with handle is my #1.  Here is #2:

http://www.arrl.org/files/file/Technology/PLN/Ultrasonic_Pinpointer.pdf

If you have these two, you should be able to pinpoint 90% of powerpole noise.

Chris
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K3ZS
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« Reply #7 on: June 02, 2012, 11:43:38 AM »

FYI W1TRC is an SK, the above author.
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WD8KDG
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« Reply #8 on: June 02, 2012, 11:53:36 AM »

May be taking this tread into another direction:

But I have to ask for those leading the green movement; these wall-warts use power all the time while plugged in an electrical outlet even if the device it is powering is off. How "Green" is that?

For those worried about greenhouse gasses, CO2 and the like; add up all these power wasting devices now in use world wide and the human species is stupid for using fossil fuels needlessly.

Craig,
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Ham radio is now like the surprise in a box of "Cracker-Jacks". There is a new source of RFI every day.
K5UJ
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« Reply #9 on: June 02, 2012, 02:33:15 PM »

I'll bet there is no medium wave or HF AM broadcasting in China or wherever these products are manufactured.
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« Reply #10 on: June 02, 2012, 03:18:30 PM »

Al,
I had a similar problem with a plastic encased SMPS wall wart for the DSL modem/router.  I enclosed it in a 4x4 metal electrical box with a receptacle. It fit just nicely inside. I used a grounded plug to ground the box, wall wart and problem went away.  That's the problem with a lot of these SMPS wall warts, the casing is not shielded so their free to emit away.
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Bob
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W1AEX
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« Reply #11 on: June 02, 2012, 05:37:10 PM »

Glad you found the offending device Al. I've noticed a definite proliferation of HF noise generators over the past 5 years. Even with decent separation between homes, a lot of consumer appliance stuff gets coupled to the grid, cable coax shielding, phone lines, and common grounds that run from pole-to-pole in every neighborhood. Samsung and Panasonic still insist on producing plasma televisions in spite of the superior picture quality of far more efficient LCD/LED models, and the videophools have the world convinced that nothing compares to a plasma. I cringe every time I see an ad for "Plasma TV Clearout!" at the local Best Buy/Walmart/Target/Sears knowing full well that it only takes one or two of those within 1000 feet of your house to make life miserable. Add to that the fact that nearly every home has an assortment of battery operated tools (Ryobi, Black and Decker, DeWalt and so on) that have switching chargers that spray RF throughout the HF spectrum. Then of course, there are the uncountable wall warts in every room of your neighbors' homes with little switching supplies that seem to love to generate 3 MHz oscillations with rich harmonic content that wanders up and down the 75 meter band. The latest HF spectrum spewers are the electronic-processor controlled stoves, washing machines, driers, treadmills, ellipticals and other such nonsense that make broadband crud. Then add in all the noise from hardware distributed by your local content providers such as ATT UVerse, Satellite systems, or your local cable company. Of course, there's always the new HF crud generating HVAC systems that are being installed in a home near yours. Add in a few electric dog fences and a couple of Ooma phones and the picture is bleak.

The hard truth is that the F.C.C. doesn't care, and neither does anyone else in a position to make a difference. Nobody but a few geeky hams and shortwave listeners are even aware of this growing crud. When my area lost power for an extended period of time following the freak October storm of 2011 it was surprising to me that none of my neighbors owned a portable AM radio. They were completely cut off since there was no cell phone coverage out here due to lack of power for the towers. I loaned out 5 portable AM radios to neighbors so they could hear the local news and get updates. Other than myself, there's really no one listening to the BCB or SW bands in my area.

We are pretty much on our own with this problem. The upside is that in the evening, when 160 and 75 meters come to life, the noise gets buried by the signals. The downside is that day time operation on those 2 bands can be problematic at my location at this point. I've resorted to defensive measures when the transmit antenna picks up too much trash and have a couple of "quiet" antennas (85 foot loops fed with RG-6) positioned as far from noise sources as possible. I'm looking at the broadband Pixel RF Pro1B preamplified-rotatable receive loop as another interesting toy to play with as well. Ah well, it's only a hobby...
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n1ps
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« Reply #12 on: June 02, 2012, 08:29:01 PM »

yup...stock up on some large #31 or 43 donuts.  Wrap abt 10 turns of the power cord thru the core.  Use an extension cord if you need to.  TV deflection cores work OK too.  I snubbed out a half dozen consumer electronics noise generators around the house. 

The following emitted birdies or hash on 75 meters: DVD player, satellite receivers, printers, cable modem, CD player and others I cannot recall.

If you see a ferrite bead as an integral part of the electronic device power cord....expect trouble.  Expect trouble anyway with any CE device.  That nice low price DVD player comes without a power transformer probably. 

I can hear it when I drive around mobile while listening to 75 (and also on 2 meters). Many houses radiate like a sick beacon.  And the numbers are growing.  Glad my car isn't fly by wire.... Cool

Peter
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« Reply #13 on: June 04, 2012, 09:20:34 AM »

Plasma vs. LCD = additive light vs. subtractive light

LED is additive light.

They are not quite the same visually. I don't know if it makes any difference to me in terms of watching a TV show, but if ur interested in color rendition for some strange reason, all of it matters. To some people it seems to matter. Fwiw, fyi, and all of that find business stuff.

                       _-_-bear
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W8IXY
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« Reply #14 on: June 04, 2012, 10:58:47 AM »

At the Dayton Hamvention in 2011, at the FCC forum, I raised my hand, was recognized, and asked Bill Cross if the FCC was doing anything about the proliferation of devices that spew RFI.  He referred the question to one of the engineers at the Chicago office, who happened to be sitting almost right next to me.  The Chicago FCC engineer said that there was not much that the FCC has done, or could do, to "police" the RFI from cheap (and not so cheap) devices primarily because they did not have the personnel or dollars to spend on RFI issues.

So, this year at the 2012 Hamvention FCC forum, before the forum got under way, Bill was seated in the back of the room, and I walked up to him and asked the same question about RFI.  Bill said, someone from the last year asked the same question.  (He remembered!)  I told him that was me.  His answer was that nothing about RFI issues was any different this year compared to last year.

So, I conclude that we are on our own most of the time to solve our individual issues ourselves.  We need to be sure whatever devices we choose to use are RFI clean.  Hope our neighbors are understanding about devices they have that cause interference to us, and accept our assistance in replacing (even if we have to pay for them) the RFI polluters.  And, hopefully get assistance and cooperation from our power companies, etc.

In the past 3 or 4 years, at my smallish suburban location, I am amazed at the RFI coming from a whole bunch of disparate sources.  One or two small RFI generators were bad enough, but often there is a cumulative effect that creates the havoc.

Makes one wish that we could tune up on a certain frequency, and the offending device would "move" or shut down, like the "woodpecker" did several decades ago.

73
Ted  W8IXY
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KM1H
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« Reply #15 on: June 04, 2012, 04:08:43 PM »

Ive used the breaker panel and portable radio to nip noise in the bud for decades, even before all this new fangled electronics. Being a hard core 160/80 CW DXer I wont tolerate being QRMed by my own house.

As far as ferrites a 43 mix is about useless at those low frequencies. Ive used 75 and 77 mix in the past but now use only FT240-31 large toroids for line cords, wall wart cables, and RG6 on the cable modem and TV's.

The large 43 mix beads work fine as sleeve baluns over RG-11 and 213 size cables and the smaller ones over RG-58 thru 6 and 8X. That keeps a lot of the neighbors noise from being picked up.

Another thing Ive done is build brute force AC line filters with a 3dB cutoff of 100KHz which has stripped a lot of the crud coming in on the lines. Those are used with all the PC's and at the ham benches. A true isolation transformer with a copper Farrady shield will also remove a lot of crud.

Carl
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W1RKW
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« Reply #16 on: June 04, 2012, 04:31:14 PM »

So, is it safe to say that these emitters of RFI are not Part 15 compliant, the FCC is not enforcing Part15 compliance let alone determining if they meet Part15 compliance.  Then abolish the FCC.
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Bob
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His fear was when I turned it on for the first time life on earth would come to a stand still.
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