Re: HUM_FORUM: HUM_FORUM: HUM_FORUM: Re: Arne, Wilderness Areas
- Are Schumann resonances a possible source? I am on a ULF-ELF group and watch the monitorings they post there. I haven't built my own Schumann receiver system yet but one of these days I'll get around to it.ZackOn Thu, Jun 4, 2009 at 12:27 PM, Joe Breskin <joe@...> wrote:
I am an antenna guy too
And we have done a lot of early stage experiments looking for heterodyned RF sources (cabletv/internet, powerlines, interactions between current carrying lines, etc) and also at ways this could be being broadcast around the neighborhood using the ground or water mains - especially via electrical groundloops.
We have productively involved both the powerline folks and the cable tv/internet folks and disconnected both power and cable in the neighborhood, including physically removing line-powered cable RF amplifiers on poles, to no conclusive benefit. The cable folks scan their system with an antenna like the FCC uses to look for pirate radio stations (I did that when i was a kid) but their antennas and pretty primitive and only look a the bands they are required to monitor
The problem at least around here, from my POV as a researcher. is disclosure laws: if people actually talk about it (i.e participate in a formalized experiment or study that looks for a LF modulated electrical potential between say the ground rods in a neighborhood or the water or sewer mains in the community) it potentially creates liability, and it seriously limits their options for selling their home and moving to someplace that they don't hear the hum - if such places actually exist.
Which means, I suppose, that to genuinely satisfy my curiosity (or at least to euthanize yet another hypothesis) I/we have to design a method that can capture precise information about ground potential (voltage, current & frequency) w/o actually connecting wires to people's grounding rods ...
So mostly I watch this list hoping somebody stumbles on something that attenuates their response to the hum
--- In firstname.lastname@example.org, Zack Widup <w9sz.zack@...> wrote:
> Hi Joe,
> I joined this group a few weeks ago but haven't posted anything yet. I was
> on Bill Beaty's TAOSHUM-L list many years ago. (Were you on that?)
> I do not hear the hum but I'm interested in the phenomenon. I'm an
> electrical engineer with experience in RF through the microwave and
> millimeter-wave region. I haven't built any equipment to try to record the
> hum yet.
> Back in the 90's no one had any idea what was causing the hum in most cases.
> I'm guessing some sources have been found since then but many cases exist
> where it's still a mystery. Most of the people who heard the hum back then
> said it was internal, i.e. they were not actually hearing it with their
> ears, if I recall correctly.
> On Thu, Jun 4, 2009 at 9:31 AM, Joe Breskin <joe@...> wrote:
> > --- In email@example.com, Chris Russell <corbomite@> wrote:
> > >
> > > Hello,
> > >
> > > > What you describe is the perfect place to conduct a few experiments. If
> > you
> > > > happen to go there again, consider taking a large battery powered
> > drill, a
> > > > small microphone and a good tape recorder. Trees are excellent
> > conductors of
> > > > electricity, radio waves, and most important, sound. You could drill a
> > large
> > > > hole in a tree, insert the microphone, seal it off inside the tree
> > against
> > > > outside noises, record. Playback. You could see if the hum is being
> > picked
> > > > up by the tree.
> > >
> > > I would advise caution when using this approach. A tall tree might
> > > experience winds at the top that are not easily discernible at ground
> > > level, and it's not outside the realm of possibility that some sort of
> > > resonance could be induced in the tree. That could result in bad data
> > > being collected.
> > >
> > > > There are other possible experiments that could be carried out? Any
> > > > suggestions from others in the group?
> > >
> > > A tree stump might provide a better result. I suppose if I were really
> > > looking for ground conducted sound, I would find a large, flat rock,
> > > lay a piezoelectric sensor on top, and then sandwich that under
> > > another reasonably heavy rock. I probably also wouldn't trust a tape
> > > recorder to the task; a laptop with a sound card that's been shown to
> > > be sensitive enough at low frequencies would be a better choice; a
> > > laptop with an external sound card designed for high quality sound
> > > would be even better. Huge bonus points if the recording is made
> > > available to the group so that signal analysis can be performed.
> > >
> > > If it were that easy to record the Hum, I suspect someone would have
> > > done it by now, but it would be interesting to have an open-source
> > > type of effort wherein all interested parties could look at the data
> > > themselves.
> > >
> > > -Chris
> > >
> > I am NOT a hum sufferer, but have been "in the loop" on hum discussions in
> > this community for at least 20 years.
> > I have made recordings using some pretty good recording tools: marantz
> > PDM671 digital field recorder and pretty high quality commercial hydrophone
> > (expensive, piezoelectric, self-powered, captures the sounds of scurrying
> > crabs, clicking clams, and other creatures in the bay).
> > Using this rig, I had some interesting though somewhat inconclusive luck a
> > few winters ago recording the sounds of a humming house by immersing the
> > hydrophone in the toilet tank on the second floor, powering the marantz from
> > an external battery pack, and recording MP3 or BWF formatted WAV files
> > directly to a large CF card.
> > This setup provides a data logger (with quieter mic preamps, no fan and
> > lower power consumption than the laptop + USB soundcard/preamp option) and
> > it can record long enough to get a continuous recording through the
> > relatively car-free period of the night (11 PM - 7:00 AM).
> > With no input filtering it records pretty flat all the way down to DC and
> > and is sensitive enough to "hear" the ticking of every battery powered wall
> > clock in the house, any appliance turning on or off, any footfalls on any
> > floor that's connected to the water system, and any speech taking place
> > anywhere in the house - even pillowtalk - and a plethora of activities
> > connected to the house via the water meter at the street, with the system's
> > noise-floor at around -60 dB.
> > When dawn comes, it does not "hear" the birds start to sing, but it does
> > "hear" individual car engines starting and cars driving away, some of them
> > many blocks away, conducted through the ground, through the City's water
> > system.
> > Analyzing these recordings (in a neighborhood where several other houses
> > are plagued by hum) I have found some low frequency components, most
> > centered around 12Hz that appear to be composed of several asynchronous
> > sources modulated at around 2-5Hz at around -56 dB but this system has not
> > conclusively captured the "hum"
> > The nearest suspect mechanical sources are a microwave installation about 4
> > blocks north and a sewer lift station 4 blocks blocks west. I have tried, so
> > far unsuccessfully, to get access to power-on/power-off data for the sewer
> > pumps. This is not impossible, just on/off time is not logged by the
> > wastewater people.
> > The owner of one of the houses in this neighborhood has created a test well
> > for me, casting a 4" diameter concrete hole for me to fill with water and
> > drop the hydrophone down, to measure the sound captured by a large concrete
> > patio-like slab that might give us a much better low frequency
> > "antenna/resonator" than the water pipes since the wavelengths in the 5 - 12
> > Hz range are very long, and I can excite the slab to measure it's resonance
> > peaks and how impulses decay.
> > Who else is currently actively trying to record the Hum and how are you
> > doing it?
> > ------------------------------------
> > Posting Guidelines:
> > 1. The orientation of this forum is scientific, with everything that
> > implies. Reasoned and articulate criticism of ideas and theories is
> > welcome.
> > 2. The following are not allowed: personal attacks, gratuitous profanity,
> > "kook" posts, and supernatural explanations.
> > 3. Limit posts to those that are necessary and have substantive content.
> > In general, no more than three per person per day.
> > 4. If you hear the Hum, please post your location at:
> > www.frappr.com/humhearersYahoo! Groups Links
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3. Limit posts to those that are necessary and have substantive content. In general, no more than three per person per day.
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> -----Original Message-----You certainly haven't. The Hum is generally described between 30 and 80 Hz.
> From: firstname.lastname@example.org [mailto:email@example.com] On
> Behalf Of Joe Breskin
> Analyzing these recordings (in a neighborhood where several other
> houses are plagued by hum) I have found some low frequency components,
> most centered around 12Hz that appear to be composed of several
> asynchronous sources modulated at around 2-5Hz at around -56 dB but
> this system has not conclusively captured the "hum"
You will record LF rumble such as you describe everywhere from many
(including natural) sources, even out in the wilderness due.
FWIW the PMD671 has rather noisy mic preamps (I repair these in my day job).
But the level that people hear Hum is not subtle, so that shouldn't be a
>Search the archives for "Earthworks" and you will get the details of my
> Who else is currently actively trying to record the Hum and how are you
> doing it?
- Also search the message archive here for "aggregate rumble" and you'll
find links to my floor slab recording via a levitated piezo, and stereo
comparisons to two other recordings (the original of one - Surrey -
seems to have evaporated) and one of Moir's Auckland recordings.
I've spoken to our water utility engineering group about the well pumps
here in Cape Coral and visited two of them, one with an induction motor
drive and one with VFD. I listened to the downpipe on each with a
contact microphone (an electret) and found nothing that sounded like
what we seek. The induction drive spins up quickly to 180Hz and 540Hz
principal components while the VFD slowly spins up and settles at
~400Hz. All of the well pumps here (several dozen of them over a few
square miles) are set at about 750 feet depth and run irregularly as
dictated by demand and the control system's load distribution criteria.
These pumps were ruled out as my source, although they surely contribute
to the earth rumble I've repeatedly captured. The closest is about a
mile north of my location.
I've also investigated the sewage system here. There are lift stations
all over the city which are all induction drives. Each cycles as
required and typically runs for a minute per cycle. I can see harmonics
from one of them on a VLF loop (and also could on an E-Field whip before
switching to the loop) that I operate and stream continuously
(http://22.214.171.124/vlf9.m3u). These, also, sound nothing like The Hum.
- Hi Tom,
Looked extensively at your drawings, very interesting. Go for it, some
substantive progress needs to be made on the issue. Your idea seems to
be well thought out.
My idea with the strain gauge and large metal disk would be to increase
the surface area of the device significantly more than a microphone
could offer, with the hope that the additional area would move the disk
sufficiently to produce a reasonable and replicable output from the
strain gauge. Also, the idea of examining the effect that the HUM may
have on the disk by using an oscilloscope may allow an interpretation
not simply based on audibility.
It's just a thought. I am going to contact my aspiring inventor friend
and try to pique his interest.
Oddly enough, the HUM seems to have disappeared from my area, my wife
heard it a little in the country last weekend, but in the city, silence.
--- In firstname.lastname@example.org, Tom Becker <gtbecker@...> wrote:
> > ... the use of a fairly large metal diaphragm with a strain gauge
> centered on the plate may show the effects of the HUM, rather than
> conventional microphone technologies...
> Perhaps, but that sounds like a large conventional microphone, I
> Jim. Most mics have a diaphragm with a magnetic (a dynamic mic) or
> electric (capacitive or piezo) motion sensor, usually centered on the
> The thing I'm tinkering with is a microphone variant, a pair of
> piezo-coated copper disks that are magnetically levitated - in an
> attempt to measure gravity modulation or noise. It makes a great
> seismometer when the disks are summed in phase; out of phase, they
> cancel except for the different motions imparted on two differing
> that they support. This is a small device, but very sensitive.
> http://rightime.com/Hum/Gravity/Floater3.bmp A simple one looks like
> this: http://rightime.com/Hum/Gravity/DSCN5317a.JPG