[TangerineSDR] [hamsci-grape] Re: [HamSCI] Power Outage Detected by VLF System

Thu Dec 7 17:19:22 EST 2023

Phil,

I very much appreciate these resources you provided! I especially love the
first paper. It also explains why I have seen what appear to be ionospheric
propagation effects of powerline radiation in some of my plots,
specifically at dawn when D layer absorption begins to kick in and
regional/local load is low enough so those emissions don't dominate the
ones that undergo waveguide propagation. I can't access the system now, but
I will pull a plot when I can and post it here.

Thanks again.

Jonathan
KC3EEY

On Wed, Dec 6, 2023 at 7:38 AM Phil Erickson <phil.erickson at gmail.com>
wrote:

> Hi all,
>
>   We should also emphasize that power line radiation is not just local.
> In case you hadn’t seen it, power line harmonics have also been detected in
> near-Earth space right out to the edge of the ‘VLF bubble’ and beyond
> (bubble extent = the plasmasphere boundary layer, 14000 - 20000+ km
> altitude) essentially out to the extent of VLF transmissions and those
> latitudes where humans live.  This was discovered long ago by the Stanford
> group (Don Carpenter, Chung Park, etc.) using ground based VLF whistler
> observations in the Antarctic and Arctic (e.g. Roberval in Canada).
>
> https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JA080i031p04249
>
> https://link.springer.com/article/10.1007/BF00173690
>
>   DEMETER satellite data, at 600 km altitude, has also clearly detected
> power line harmonics in the topside ionosphere in its data.  See this
> article and related ones:
>
> https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2006JA012134
>
>   So it is truly everywhere.
>
> 73
> Phil W1PJE
>
> On Wed, Dec 6, 2023 at 06:29 Jonathan <emuman100 at gmail.com> wrote:
>
>> Mike,
>>
>> At ELF, ULF, and VLF, powerline hum (including harmonics) is omnipresent
>> and comes from many different sources, meaning the VLF receiver detects
>> power line emissions from the house, surrounding houses, surrounding power
>> lines, both access, distribution, and transmission lines, and anything else
>> supplied by mains within hundreds of miles. There is never any “one source”
>> of powerline hum and it will always be present on a VLF receiver. In many
>> VLF applications, power line hum is filtered so as long as it’s not at high
>> enough levels that it causes clipping at the data acquisition input. I
>> filter in my signal processing chain, but before I do, I continually
>> monitor levels of 60Hz and 180 Hz
>>
>> Steve,
>>
>> I’ve heard of many cases where solar panel inverters create lots of noise
>> at HF, but few have been characterized at VLF. I would imagine making these
>> inverters VLF quiet will take much more legwork, as it always does with
>> VLF.
>>
>> With vlfrx-tools and Spectrum Lab, an adaptive mains filter is included
>> and is very effective. Here <http://www.abelian.org/vlfrx-tools/hum.mp3> is
>> a sample containing 50 Hz hum and harmonics with the adaptive mains filter
>> in vlfrx-tools. After a few seconds, it locates the fundamental and
>> odd/even harmonics and adaptively notches them out. It tracks them as the
>> line frequency changes throughout the day. Once it kicks in, you can hear
>> sferics and the VLF spectrum quite easily. It notches harmonics up to 6 kHz
>> by default, but can notch up to 8 or 10 kHz in mains-heavy environments.
>> Using it, you can easily hear natural radio events and amateur radio
>> transmissions in the VLF band.
>>
>> Dana,
>>
>> Mains harmonics usually extend up to ~6 kHz but could extend much higher
>> in heavy harmonic environments. Those noises you hear are not usually
>> related to power line emission, but could be synchronous to 60 Hz because
>> they originate from power converters synchronous to power line frequencies.
>>
>> Jonathan
>> KC3EEY
>>
>>
>>
>> On Tue, Dec 5, 2023 at 1:01 PM Eric Nichols <kl7aj72 at gmail.com> wrote:
>>
>>> Golden Valley Electric association up here has always been very
>>> competent and eager to solve noise problems.   Probably because the head of
>>> engineering for many decades was a ham.  I believe he also trained his
>>> underlings well...the systems seems to be incredibly clean.   This may not
>>> be the case elsewhere, but I'm very grateful for our power folks up here.
>>>
>>> 73!
>>>
>>> Eric
>>> On 12/5/23 06:45, Dana Whitlow wrote:
>>>
>>> David,
>>>
>>> As I've tried to emphasize above, all i've looked at so far is the
>>> "raspy buzz"
>>> impulsive form of noise, which I've normally tended to regard as the most
>>> objectionable.  However, I do recognize that the "fuzzy hum" form would
>>> likely turn out to be more of a problem for very narrowband analyses,
>>> which
>>> is my usual case, if a harmonic should land too close to the signal band
>>> of
>>> interest.
>>>
>>> Many of my experiments have involved a final measurement bandwidth of
>>> less than 1 Hz, so I should be alert to this possibility.
>>>
>>> Dana
>>>
>>>
>>> On Tue, Dec 5, 2023 at 9:38 AM David G. McGaw <
>>> david.g.mcgaw at dartmouth.edu> wrote:
>>>
>>>> Generally, transformers do not make noise.  All the electronic loads in
>>>> the neighborhood on the line will create a certain amount of harmonics,
>>>> though the larger loads are required to include power factor control to
>>>> minimize this.  Defective insulators or branches and such across the wires
>>>> do create pulse noise.
>>>>
>>>> You are correct, if you can localize the source of the interference,
>>>> the power company will fix it.  They do not have the capability of finding
>>>> it themselves so rely on us to find and report it.  In New England, we have
>>>> created a task force under ARRL to help, see
>>>> <https://nediv.arrl.org/spectrum-protection-utilization/>
>>>> <https://nediv.arrl.org/spectrum-protection-utilization/>, "Noise
>>>> Identification".
>>>>
>>>> 73,
>>>>
>>>> David N1HAC
>>>>
>>>> On 12/5/23 10:34 AM, Dana Whitlow wrote:
>>>>
>>>> Michael,
>>>>
>>>> Since there is no electrical connection to the top end of the pipe,
>>>> basic EM theory says that the pipe is actually irrelevant to common-
>>>> mode current flows.  Whether or not the pipe provides any shielding
>>>> for E-fields is another matter, of course.  I have not looked at the
>>>> E-field issue, because even if the pipe is *not* grounded, the 40 ft of
>>>> unshielded wiring from the pole to the top of the pipe would by far
>>>> be the dominant radiator, and there is nothing I could do about it.
>>>>
>>>> Your mention of the transformer itself being noisy is scary, because
>>>> the ultrasonic test would almost certainly fail to detect such a
>>>> problem, probably making it rather difficult to persuade the power
>>>> company to change out the transformer "on speculation".
>>>>
>>>> As far as power outages are concerned, I'd love to see a county-wide
>>>> outage at night in clear WX, just so I could enjoy a dark sky for a
>>>> change.  But preferably in the summer, you understand.
>>>>
>>>> Dana
>>>>
>>>>
>>>>
>>>> On Tue, Dec 5, 2023 at 9:01 AM 'Black Michael' via HamSCI <
>>>> hamsci at googlegroups.com> wrote:
>>>>
>>>>> Make sure your metal pipe is grounded to the ground rod at your
>>>>> breaker panel.
>>>>> You should see almost 0 Ohms between the pipe and ground connection.
>>>>>
>>>>> It may be more likely coming in the wiring.  Do you have an oscope you
>>>>> can use to see what's on the wires/pipes?
>>>>>
>>>>> The power outage is a good clue and you may be able to get the power
>>>>> company to come out based on that observation.
>>>>> Noisy transformers are common and they are required to replace them.
>>>>>
>>>>> Mike W9MDB
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Tuesday, December 5, 2023 at 08:55:58 AM CST, Dana Whitlow <
>>>>> k8yumdoober at gmail.com> wrote:
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Michael,
>>>>>
>>>>> I've only tried that once, during an episode of the raspy buzz form
>>>>> of the problem.  I used a battery-powered AM radio in the AM BC
>>>>> band so that I could use the ferrite bar antenna.
>>>>>
>>>>> The breaker panel is located on the outside of the house, and the
>>>>> incoming power comes down through a metal pipe which extends
>>>>> up through the eave, with the wiring from the pole entering said
>>>>> pipe through the usual arrangement used to keep rain out.
>>>>>
>>>>> Anyway, before I turned off any breakers I moved the radio around
>>>>> and concluded that the noise was manifested (at least primarily) as
>>>>> a common-mode current through the metal pipe.
>>>>>
>>>>> Next I began turning off individual breakers to see if the problem
>>>>> was confined to a single circuit, but apparently it was not.
>>>>>
>>>>> Then, with all the individual breakers back on, I opened the master
>>>>> breaker, with the same result.  The noise remained in all its glory.
>>>>>
>>>>> I suspect a problem with the pole about 40 ft from the house, but
>>>>> did not have an ultrasonic snooper at the time.  I acquired one of
>>>>> those only very recently, but have not yet put it to the acid test.
>>>>>
>>>>> I have not yet found anybody selling giant clamp-on ferrite chokes
>>>>> for  "cables" about 4 inches in diameter  :-)
>>>>>
>>>>> Also, I have not yet investigated the fuzzy hum form of interference.
>>>>>
>>>>> Dana
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Tue, Dec 5, 2023 at 8:25 AM 'Black Michael' via HamSCI <
>>>>> hamsci at googlegroups.com> wrote:
>>>>> > Can we assume you've tested cutting power to your house so you can
>>>>> determine if it's YOUR house causing any of the hum?
>>>>> >
>>>>> > Mike W9MDB
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> > On Tuesday, December 5, 2023 at 05:34:33 AM CST, Jonathan <
>>>>> emuman100 at gmail.com> wrote:
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> >
>>>>> > A benefit to powerline hum (radio emissions of 60Hz and harmonics
>>>>> radiated by power lines) being omnipresent even in the most RF quiet
>>>>> locations is that you can monitor local and regional power outages very
>>>>> closely with a VLF receiver. A local power outage occurred around the
>>>>> vicinity of the VLF receiver at Spring Brook Township, PA. Here is a plot
>>>>> of the amplitude level of 180 Hz, a harmonic of 60 Hz, showing some power
>>>>> loss at ~2030UT and completely at ~2100UT:
>>>>> >
>>>>> >
>>>>> > Here you can see the hum level in greater temporal detail. What is
>>>>> so impressive about this power outage is how low the hum levels got. I will
>>>>> be pulling the audio file and listening to this period. Unfortunately,
>>>>> there were no whistlers or dawn chorus, but hum levels this low are quite a
>>>>> treat:
>>>>> >
>>>>> >
>>>>> > After the power outage ended, there were some interesting spikes,
>>>>> possibly due to inductive inrush, then hum levels returned to normal:
>>>>> >
>>>>> > The VLF system was on a UPS during the power outage, so
>>>>> there definitely is benefit to keep the system up and running during local
>>>>> power outages, especially if the magnetosphere decides to be generous.
>>>>> Power grid studies are often done using VLF receivers and the benefit is
>>>>> that no attachment to the power lines are required.
>>>>> >
>>>>> > Jonathan
>>>>> > KC3EEY
>>>>> >
>>>>> >
>>>>> >
>>>>> > --
>>>>> > Please follow the HamSCI Community Participation Guidelines at
>>>>> http://hamsci.org/hamsci-community-participation-guidelines.
>>>>> > ---
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>>>>> > To view this discussion on the web visit
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>>>>> .
>>>>> >
>>>>> > --
>>>>> > Please follow the HamSCI Community Participation Guidelines at
>>>>> http://hamsci.org/hamsci-community-participation-guidelines.
>>>>> > ---
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>>>>> .
>>>>> >
>>>>>
>>>>>
>>>>> --
>>>>> Please follow the HamSCI Community Participation Guidelines at
>>>>> http://hamsci.org/hamsci-community-participation-guidelines.
>>>>> ---
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>>>>> .
>>>>>
>>>>> --
>>>>> Please follow the HamSCI Community Participation Guidelines at
>>>>> http://hamsci.org/hamsci-community-participation-guidelines.
>>>>> ---
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>>>>> .
>>>>>
>>>> --
>>>> Please follow the HamSCI Community Participation Guidelines at
>>>> http://hamsci.org/hamsci-community-participation-guidelines.
>>>> ---
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>>>> <https://groups.google.com/d/msgid/hamsci/CADHrwpeHA9SDaKf_hUY1rKt-aDeJJrh-P-ZOhcEZuLgRNr1h%2Bg%40mail.gmail.com?utm_medium=email&utm_source=footer>
>>>> .
>>>>
>>>>
>>>> --
>>>> Please follow the HamSCI Community Participation Guidelines at
>>>> http://hamsci.org/hamsci-community-participation-guidelines.
>>>> ---
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>>>> To view this discussion on the web visit
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>>>> <https://groups.google.com/d/msgid/hamsci/7fba57a4-23ad-48c3-b245-34e874f1c86e%40dartmouth.edu?utm_medium=email&utm_source=footer>
>>>> .
>>>>
>>> --
>>> Please follow the HamSCI Community Participation Guidelines at
>>> http://hamsci.org/hamsci-community-participation-guidelines.
>>> ---
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>>> <https://groups.google.com/d/msgid/hamsci/CADHrwpeP7tZvK8Q1zjP_8JA_wtPwBCr5g4m%2BiKfR9UtjyLrYdg%40mail.gmail.com?utm_medium=email&utm_source=footer>
>>> .
>>>
>>> --
>>> Eric P. Nichols, KL7AJ
>>> AlasKit Educational and Scientific Resources138 Shenandoah Drive
>>> Fairbanks, AK 99712 <https://www.google.com/maps/search/138+Shenandoah+Drive%0D%0AFairbanks,+AK+99712?entry=gmail&source=g>
>>> (907)371-7120www.alaskit.netkl7aj72 at gmail.com
>>>
>>> --
>>> Please follow the HamSCI Community Participation Guidelines at
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>>> .
>>>
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>
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