In digging into VLF receivers and related info I found an interesting possible correlation to hum hearing, weather and earth changes. I did not thoroughly read each page and am not certain if this info is applicable to Glens work but I am throwing it on the table for all to read. Here's what I found:
Exerpt from the web pages listed above the blurb.http://www.auroralchorus.com/wr3gde.htm
POCKET-PORTABLE WR-3 NATURAL-VLF-RADIO PHENOMENA RECEIVER LISTENING GUIDE, By Stephen Paul McGreevy
This Listening Guide was first begun in mid-1991 and recently updated again May 2010)
Welcome to the realm of extreme and very-low-frequency (ELF/VLF) "Natural Radio!" The WR-3 is an electric-field ("E-field") type of "whistler receiver" specifically designed to monitor naturally-occurring VLF radio emissions of Earth that occur in the 300-11,000
cycles-per-second (0.3-11 kHz) audio-frequency ELF/VLF radio spectrum. It employs a telescoping whip antenna (BNC-mount) to receive VLF signals and requires stereo-mini headphones to be plugged into its output for listening.
Earth-along with several other planets in the Solar System including Venus, Jupiter, Saturn, Uranus and Neptune - produces a variety of naturally occurring radio emissions at the lowest end of the radio spectrum (< 10 kHz), primarily in the form of electromagnetic (radio) impulses generated by ongoing lightning storms and also from the Sun's solar wind interacting with the magnetic envelope surrounding Earth, called the "magnetosphere." A large variety of unusual and beautiful Natural Radio sounds can be heard at ELF/VLF frequencies. These naturally-occurring radio signals are the subjects of ongoing scientific research by both amateur and professional groups, and are being monitored both on the ground by users of the
WR-3, other ground-based VLF receiver systems, and by unmanned space probes and satellites.
It is at these lowest frequencies of the radio spectrum in which no man-made signals are assigned, that planet Earth's own mysterious radio emissions have been happening for eons. These fascinating "sounds" are "primal radio"-indifferent to the affairs of humankind-and insight into the causes of these ancient phenomena has only begun to be unraveled in the past 50 years, particularly commencing with the International Geophysical Year beginning in 1957.
WHEN TO LISTEN FOR NATURAL RADIO PHENOMENA AND WHERE IN THE WORLD THEY OCCUR:
(Much of the information following should be used concurrently with the above sources of geo-magnetic information for best listening results.)
Statistically, the time between local midnight and an hour after sunrise is when the greatest amounts of whistlers are heard, although dusk to midnight may reveal
substantial whistler activity, and even (though not very often) loud whistlers may be heard a couple of hours before sunset. Over the long term, the period from two hours before sunrise until an hour after sunrise is the optimum time to listen for natural VLF phenomena of all sorts, as the amount of sferics (lightning stroke pops and crackling) are less -- natural VLF radio phenomena are not as "buried" under the sferics as in the evening when lightning storms are more numerous. Also, magnetospheric conditions are optimum around morning twilight time and an hour before for best whistler listening.
Interestingly, between April 1996 and March 1997, I had been hearing good whistler events during the DAYTIME and particularly late afternoon before sunset! Many times, these whistler events die out after sunset and are not heard at sunrise. But, after that through December 1997, whistlers were once again more frequently heard between 2 - 6 a.m. local
I have no serious power line noise problem on VLF (0 to 22 KHz on the SM6LKM SAQ downloaded VLF receiver on http://web.telia.com/~u33233109/saqrx/saqrx.html
There is also no power line noise problem on the Kenwood TS480HX which receives between 20 kHz to 30 kHz. I use the 10 kHz clarifier to listen below 30 kHz. http://www.herostechnology.co.uk/pages/VLF_LF_Converter.htmlhttp://www.cliftonlaboratories.com/jackson_harbor_press_vlf_converter.htmhttp://www.radio-ware.com/products/pla1.htmhttp://www.stormwise.com/vlfaq.htm
Like shortwave radio,
VLF can be reflected
from the upper atmosphere. But what happens when the waves become too big to fit? Does the upper atmosphere expand to allow the waves room pass thru? No! There is a point in frequency where radio waves get too big to fit between the 35 to 60 miles space between the earth and the upper atmosphere. This point is 1600 Hz (click to listen). These radio waves are so low in frequency that you can actually hear them with your ears, when they are transformed into sound waves by a speaker. Radio waves below 1600 Hz can not travel too far beyond 60 miles.
Waves below 1600 Hz can travel by conduction through the earth itself. The earth's surface and underground area is very large and the waves below 1600 Hz have plenty of room to travel underground. Frequencies below 1000 Hz are used for earthquake research and other scientific studies. Lightning static drops out very quickly below 1600 Hz.
Voice and musical sounds of 20 Hz through 20 KHz, can be
transformed into VLF radio waves when detected by a microphone. A tape recorder works by recording the VLF waves onto a magnetic cassette tape. During playback, a sensor detects the VLF radio waves from the tape as it is pulled past the sensor. An amplifier boosts the VLF radio waves and sends them to the speaker. The speaker vibrates and produces the sounds that you hear!
AM and FM radio broadcasts are actually carrying voice and music frequencies - 20 Hz to 20 KHz, this is VLF being carried through the air on much higher-frequency radio wave, but it is not VLF until it flows as electrical current to your radio's speakers. http://www.w6ze.org/Heathkit/Heathkit_016_HD1420.pdfhttp://martykaiser.com/vlf59-10~1.htmhttp://k1el.tripod.com/VLF.htmlhttp://www.vlf.it/trond2/10-15khz.htmlhttp://www.vlf.it/trond2/below10.htmlhttp://home.pon.net/785/equipment/build_your_own.htm
There are two ways to intercept a VLF signal: electromagnetically (B-Field) or electrostatically (E-Field). Electrostatic pertains to the charge voltage or current wave of the signal. Electromagnetic relates to the magnetic influence of a signal.http://www.stormwise.com/page28.htmhttp://www.stormwise.com/project10.htmhttp://www.dxzone.com/dx27449/vlf-broadcast-stations-10-150-khz-.htmlhttp://www.omen.com/vlf.html
WA7KGX VLF Monitoring
Signals in the 10 to 30 KHz range are used to send information and commands to submerged submarines worldwide. Most of these VLF stations transmit nearly continuously at constant power. Sudden changes in signal propagation may indicate interesting solar events, or even a strong gamma ray burst.http://udini.proquest.com/view/elf-or-vlf-phased-array-generation-pqid:1957930361/
ELF/VLF phased array generation via frequency-matched
steering of a
continuous HF ionospheric heating beam
ProQuest Dissertations and Theses, 2009
Author: Morris Bernard Cohen
The radio spectrum between 300 Hz and 10 kHz (ELF/VLF) has broad applications to global communication, remote sensing of the ionosphere and magnetosphere, and subterranean prospecting. While lightning is a dominant source of these radio waves, artificial generation of these waves has posed an enduring challenge to scientists and engineers, due to the extremely long wavelengths (30-1000 km) and the lossiness of the Earth's surface at these frequencies. Recently, ELF/VLF waves have been successfully generated by high frequency (HF, 3-10 MHz) heating of the lower ionosphere (60-100 km altitude), which changes the atmospheric plasma conductivity. In the presence of natural currents such as the auroral electrojet, ON-OFF modulation of this HF energy can impose an ELF/VLF alternating current onto those
natural currents. This technique turns the lower atmosphere into a large antenna, which radiates energy downward into the Earth-ionosphere waveguide and upward into the magnetosphere. While this technique remains one of the few means of reliable ELF/VLF wave generation, HF to ELF/VLF conversion efficiencies remain quite low. Utilizing the 3.6 MW HAARP HF heating facility in Alaska, we show that proper utilization of motion of the HF beam can boost the generated ELF/VLF wave power by as much as tenfold. Furthermore, as a result of having effectively created the world's first controllable large-element ELF/VLF phased array, directional launching of this energy becomes possible. We utilize theoretical models of the HF heating and cooling process, and of ELF/VLF wave propagation, to illuminate the observations and identify the physical mechanisms underlying the wave generation, particularly as it relates to motion of the HF beam.