Transistor Radio as an aid to the Hum type detection by Dr Chris Barnes, Bangor Scientific Consultants
Abstract
The characteristics of the
Hum are briefly described. Instances of the Hum are heard by hearers in stationary
cars and houses hypotheses for this are given. A theoretical explanation as to
how an off-tuned transistor radio might form a Hum detector is advanced. A control experiment is performed where in
the personal experience of the author the Hum pulse repletion rate experienced
in a car with a dimming interior light is shown to coincide exactly with the rate
heard on the radio. Explanations for this are advanced. A series of experiments was performed with
the radio Hum detector in the authors’ house. Although the Hum could be heard all over the
house THE RADIO Hum detector was only able to detect the Hum quasi-periodic repletion
sequence at one specific place in the house near water piping. This fits with the notion of the Hum as being
a magneto-acoustic effect with acoustic and infrasonic components conducted by
the fabric of the house but the related electromagnetic components only conducted
by parts of the fabric of the house which can act as appropriate antennas. Whereas the transistor radio makes a sort of
Hum detector it is perhaps not as universally sensitive to Hums as afflicted individuals.
Introduction
It has long been known that a transistor radio tuned
off-station is a valuable aid to tracing electronic interference.
It has recently been proposed that one type of Hum ‘audition’,
so called Hum type 3 involves infrasound plus higher frequency magnetic
components which may have a coherent relationship ( Barnes refs). The Hum is a geo-sporadic psycho-acoustic
effect wherein afflicted individuals, mainly but not exclusively aged 50+ hear
or perceive, mainly at night, a
distracting, often distressing,
pulsating idling engine or trapped bee like noise which cannot be
readily audio recorded.
A source of the Hum wherein this hypothesis has been
positively confirmed is that due to the electrical systems of a car
particularly in the PWM signal which dims the car’s interior light upon closing
a door with the engine switched off. Hum
like effects have been perceived by both the personal experience of the author
and his wife in two different motor vehicles namely a Vauxhall Vectra CDTI 1.9 and a Renault Megane
1.5 DCI. Such Hum-like effects also
appear to maximise when this action is performed in a stationary car underneath
high voltage AC conductors or at certain key distances from either Tetra Radio
Transmitters or High Power Analogue TV transmitters (refs). In a car under
these conditions a strong electromagnetic comb spectrum can be detected
together with weak acoustic sound and infrasound. It is also understood, personal
communication, that a lady who hears the Hum in the Wye Valley of South Wales
recently reported experiencing this ‘car phenomenon’ under power lines in
Humberside, Northern England.
Another suspected source of the Hum type 3 which
individuals usually experience in their homes worldwide is thought to be due to
a combination of 2 Hz and higher infrasound
and acoustic sound and 50 Hz and 60 Hz and higher pulsating harmonics
all arising from power systems and all initially synchronously related. The precise nature of propagation of these
signals involving the Physics of the Solid Earth and the Physics and Magnetism
of the ionosphere and space beyond is truly fascinating and has resulted in
many internet publications of the present author (refs). Challenged with this one can begin to see how
very subtle structural changes in anything from an individual house to the
neighbourhood beyond can influence this propagation and cause new cases of the
Hum or bring to a close existing ones!
Most signals these days from power systems are
expected to contain some element of non –linearity and hence higher and higher
harmonics. The effect will be three fold. There will be more radiation of
harmonics to space and more chance of scattering to earth. There will hence be
more outbreaks of the Hum. Finally, advantageously, such signals, and hence the
likelihood of Hum sites, will be easier to trace using radio frequency
detection techniques. One of the
simplest and most effective of these is the off-tuned transistor radio! Indeed if one theorises that detection of
the Hum in humans involves direct hearing of its low frequency and/or
infrasonic component and (electro) magnetic detection of its higher order
components, then just perhaps the off- tuned transistor radio is the only real
tool that can give non-Hum hearers any remote semblance of perception of what
we hearers have to contend. Why is this
likely to be? Quite simply that any low
frequency components of the Hum such as acoustic and infrasonic frequencies
with associated electromagnetic fields will induce directly into the audio
amplifier circuits of the radio, whereas higher frequency components or
harmonics will induce into the radio frequency amplifier circuits of the radio
to then eventually be heterodyne down converted, and demodulated. Clearly if
these signals are of constant frequency and amplitude they will not contribute
to the audio output of the radio.
However, as previous publications of the present author have repeatedly
shown (ref) the higher harmonics of the mains frequency for example thought to
be involved in many cases of the Hum are often seen to be pulsating in
amplitude and with some with additional frequency deviation. It is these frequency and amplitude
deviations which will pass through the detector of the radio to be effectively
mixed with the aforesaid lower frequencies which in some types of Hum may
themselves be sub-harmonic sets of the aforesaid modulated higher frequencies.
It is hypothesised that somehow this or similar type of process occurs
internally in the ear and/or brain of people afflicted by the Hum
Apparatus
The apparatus used in the present study comprises a Dynasty
Electronics Ltd ‘MEGABASS’
miniature AM /FM radio type 900AF and a set of high
quality headphones, type Realistic PRO20.
A ‘Cornet’ ED75 field meter was also used for milli-guass
magnetic field measurement.
Experimental
The classic control
experiment for the Hum by personal experience of the author is the scenario of
the car vanity light PWM controller. The
author can always perceive the Hum in the two aforesaid cars under these
circumstances. The control experiment
was conducted in the author’s Vauxhall motor car and involved the author
wearing the headphones of the apparatus described above. A number of different
tones could be heard in the headphones but as the vanity light started dimming
a set of tones with EXACTLY
the same regular pulse repetition rate as that perceived without the aid of the
apparatus could be heard.
The signal maximised near to the bottom of the radio
and control console. It is presumed this
was where the ECU or a prime wiring loom is located. The magnetic field on the Cornet meter also
maximised here at about 3mG a figure which was 2.4mG greater than the
background field.
A number of subsequent experiments were conducted in
the author’s house at times when the Hum could and could not be perceived.
Results and Discussion
Ideally experiments in the house should be performed
when the mains electricity is isolated at the main consumer unit switch to
reduce extraneous sources of interference. This was only possible on one
occasion when the Hum was still audible at approximately 10am on May 13th
2012.
Use of the off-tuned radio detector was highly
instructive for reasons other than just the Hum. It proved to be an incredibly
sensitive detector of electromagnetic leakage from just about every household
and office source. Also an effect was
noticed at between 11pm and 1 am wherein very specific metallic parts of the
house seemed to have incredibly sharp resonance like amplification of powerful
short wave signals which broke through on the radio. So sharp was the
resonances that positioning the radio at one corner of the kitchen sink as
opposed to the other made an estimated 40dB difference in signal strength! Of course it is known that the ionosphere D
layer causes a broad gain effect at night but it is though this was something
additional? There is also powerful
sporadic E propagation in May, it is not known if this was involved.
One can begin to perceive that if a similar effect
happens for radiated harmonics from power systems then one can begin to see how
the Hum might tune itself to certain locations at certain times.
The author has always noted that the Bangor Hum is
perceived loudest in his downstairs toilet which a small cubicle sized room
with a several meter high sloping roof.
The experiment on 13th May was, indeed, particularly
revealing. The Hum pseudo random pulsation
frequency was heard on the 900AF but only in one very specific location in that
toilet. The radio had to be located about 35cm above ground level and
immediately adjacent to the hot and cold water pipes feeding the cloakroom
sink.
Effectively this was the breakthrough the author has
been looking for, that is to create a system which is a ‘Hum Detector’.
Differences between Car Hum
and House Hum
In the car the Hum is confined to small local
space. The mechanism for perception
might be acousto- magnetic or purely magnetic. There is so much background noise where the
author lives it was impossible to record a quiet acoustic spectrum in the car.
It is possible to theorise that extremely weak coherent acoustic and infrasonic
noise would be generated by magneto-striction and electromotive induction in the cabling and by
electrostriction and thermo acoustic relaxation in the interior lamp bulb in
response to the PWM pulses.
In the house the Hum is everywhere so the odds of it
definitely being part acoustic are much higher. The author has previously shown
how the very fabric and walls of houses generate acoustic singles. In the car all the electromagnetic components
are available locally but in the house they will need to propagate in. The very lowest frequency components will
need good antennas and indeed very low frequency signals will be received by
ground antennas. Thus the hypothesis is
that the water pipes were producing an effect for all frequencies of the Hum
rather like the resonance effect described above.
Further work
The above experiments need repeating on many more
instances of the Hum. The Hum detector needs to be applied in other locations
where Hums are present to once and for all prove that this curse is indeed the
complex magneto-acoustic effect so strongly supported by all the other work of
the present author. Furthermore only
when other afflicted individuals hear their Hum pulse and characteristic
repetition rate will they too be assured.