Now you hear me, now you don’t; Dielectric resonance enhanced thermo-acoustic microwave hearing

Dr C. Barnes, Bangor Scientific Consultants. doctor.barnes@yahoo.co.uk

Abstract

The paper looks at the hypothesis that microwave hearing could occur at levels of SAR some thousand times less than commonly observed by laboratory experiment at specific frequencies wherein the skull and hearing apparatus dielectric resonance occurs. The commonly held hypothesis that the skull and cochlea are sites for thermo-elastic detection are confirmed as is the hypothesis of the paper. The most pervasive frequencies are shown to be 220 MHz, 600 MHz, 930 MHz, 1800 MHz and 2400 MHz. The least pervasive are shown to be 380 MHz and 2100 MHz. From personal experience the author reports his personal Hum has weakened significantly since the closure of analogue television and accounts theoretically and experimentally for why this is so. Released in Beta form to benefit the scientific community references to be added in due course. Internet self -publication date 16^th July 2011.

Introduction

Over the last four decades or so several authors have reported on the experimental observation of so called microwave hearing (refs). This is a phenomenon wherein pulsed or amplitude modulated microwaves in the approximate frequency range 200 MHz to 3 GHz are reported as producing human auditory responses in the form of clicks or buzzing sounds ( ). It has been postulated that the microwaves are directly detected by the human cochlea ( ). Animal studies have shown that this is a real phenomenon in that pulsed microwaves elicit signals from the acoustic nerve of anaesthetised animals ( ).

Anecdotal reports

There are anecdotal reports of people hearing very invasive and pervasive pulsating buzzing noises mainly during the quiet of the night, the so called ‘Hum’. The present author has postulated on the Hum for several years (refs). Some cases of the Hum can be adequately explained by oversensitive hearing (ref), particularly at low and infrasonic frequencies (ref). Indeed the present author has shown that Hum like effects can be synthesised in the laboratory using combined infrasound and low frequency acoustic sound. Perhaps a more radical theory of the present author but one which has not been readily disproved is that in their experience of the Hum some humans could actually be acting as Radio Acoustic Sounders where there is Bragg matching of radio and acoustic or radio and infrasonic wavelengths ( ). People who are plagued by the Hum are usually refereed to as Hummers ( ).

Recently the author received an anecdotal report by email from a distraught individual plagued by such Hum. However for the particular individual the Hum was only perceived when hen was proximal or in line of sight with VHF, UHF and microwave radio transmitting masts or cellular base stations. The question has to be asked then; can some cases of the Hum be entirely due to electromagnetic radiation and without external acoustic component?

Theoretical considerations

Notions of the thermo-elastic conversion of microwave energy to sound have recently been proven for water and some polymers (refs). Calculations on the required power levels or specific absorption rate (SAR) required to elicit response and human sensitivity are based on plane waves impinging on a surface and does not take into account possible resonance effects. As such the power level reckoned to promote thermo-acoustic microwave hearing is of the order of one thousands times the NRPB safe limit for cellular telephone signals. Yet clearly the individual referred to in anecdotal reports above is experiencing some sort of electromagnetic hearing within the so called safe limit. Of course we have all heard of electrical hypersensitivity syndrome (REF) or have we? Perhaps we can elucidate a more scientific solution.

Most of the present theories suggest that signal detection takes place at the cochlea (ref) while some speak of bone conduction to the cochlea (ref).

The cochlea is a tiny organ the size of a pea (ref). Even the largest peas only approach about 1 cm in diameter most are about half this size. The cochlea comprises bone on the inside and bio-fluid inside. Unwound the cochlea is about 3 cm long (ref). The size of an adult human skull approximated to a box structure is approximately 22cm x 15cm x 18cm.

Given the range of frequencies quoted for microwave hearing i.e. 200 MHz – 3 GHz it is highly pertinent to calculate the properties of the skull and cochlea as a dielectric antenna, i.e. can resonant dielectric heating play a part in the detection process. Furthermore could the ear canal and external ear flap essential made of skin and cartilage also play a part? The hypothesis here is that electromagnetically sensitive hummers could be so because of perfect or near perfect resonance matching of two or more parts of their electromagnetic ‘ear’ i.e. their skull resonance might be matched perfectly with their cochlea resonance and/or with their outer ear resonance.

Thankfully, very comprehensive data on the dielectric properties of tissue types is available on line, courtesy of the Italian National Research Council, Institute for Applied Physics. At this site there is also a calculator for electromagnetic wavelength in given types of tissue as a function of its dielectric properties and a calculator of the penetration depth of electromagnetic waves into tissue.

WAVELENGTH AT	200 MHz	380 MHz	600 MHZ	930 MHz	1800 MHz	2100 MHz	2400 MHz
SKULL BONE	44cm	24cm	18.5cm	10cm	5.3cm	4.7cm	4.1cm
No.wavelengths accom.	L/2	~L	~L	3L/2	~3L+~4L	nL	nL
COCHLEA unwound 3cm
( Bone)	>	>	>	>	~L/2	N/A	3L/4
(Body fluid)	14cm	8.5cm	5.7cm	3.8cm	2cm	1.7cm	1.5cm
	>	>	~L/2	~3L/4	3L/2	N/A	2L
COCHLEA wound 1cm max	>	>	>	>	>	>
(Bone)							L/4
(Body fluid)	>	>	>	>
					L/2	N/A	3L/4
Ear canal 2.5cm cartilage	18cm	11.2cm	7.3cm	4.9cm	2.5cm	2.2cm	2cm
	>	>	>	~L/2	L	~L	N/A
Ear flap skin	17cm	11cm	7.3cm	4.9cm	2.6cm	2.3cm	2cm
	>	>	~L+L/2	N/A	~L	N/A	N/A
Ear flap cartilage circumference 11cm	N/A	L	N/A	~2L	~4L	~5L	N/A
Ear flap cartilage 6.5x3cm	>	>	~L+L/2	N/A	~L	N/A	N/A

TABLE 1

The results of calculations for the most likely component parts of an ‘electromagnetic’ ear are shown in table 1 above, where L represents the wavelength in the tissue concerned.

Discussion

The results show that both the common theories of thermo-acoustic detection are possible, i.e. that at takes place at the skin or bone of the skull or in the cochlea. Which is most relevant appears dependent on precise frequency. Furthermore the hypothesis that the structures concerned exhibit dielectric resonance i.e. can act like antennas at various frequencies across the range is also confirmed. The best length for any resonant antenna is half a wavelength or odd multiples thereof because this is the shortest length which can accommodate voltage and current components in quadrature. However, under some circumstances such as in the presence of a suitable reflector or ground-plane a quarter wavelengths or odd multiples thereof can do the same. Other lengths can be made to work with appropriate complex impedance matching. At lower VHF frequencies around 220 MHz the likely mechanism is by thermo-acoustic expansion of the skin and bones of the skull and is half wave resonance assisted. This frequency coincides approximately with VHF DAB broadcasting. It is worth mentioning that the skull would make an ideal quarter wave resonator at frequencies of about 100 MHz i.e. the VHF FM broadcast band. The present author has made a past observation that a considerable number of anecdotal Hum reports seems to arise in locations close to powerful VHF FM transmitters (ref). At low UHF frequencies 380 MHz, the frequency of the controversial emergency services TETRA transmission no half wave resonance absorption mechanism exists so unless some other form of matching is present one would not assume TETRA transmissions to be a cause of the Hum and indeed for many the Hum pre-dates this form of emission. Ignoring the fact the cochlea is coiled and in act treating it as uncoiled, at 600 MHz (a typical UHF TV frequency) a half wave resonance absorption mechanism involving the fluid in the cochlea and the skin and cartilage of the ear flap seems most probable. It is interesting to note that the present author in a previous search for infrastructure relating to the Hum has cited the 1970’s advent of the Hum in Britain as coincident with the arrival of UHF TV Broadcasting (ref) and has also explained that although UHF TV broadcasting was invented in the USA long before this they did not have it commonplace until the early 1990’s the era when the famous Taos Hum sprung up! On the basis of the above calculations, 930 MHz i.e. second generation mobile phone frequencies would appear to have a significant potential to be dielectrically resonance absorbed by the most parts of the electromagnetic hearing apparatus! One can see that at this frequency, the skull could act as a three half wave antenna, the body fluid of the cochlea as a ¾ wave antenna and the cartilage walls of the ear canal as a ½ wave antenna. Thus for some at least the ever expanding mobile phone industry might possibly account for the ever expanding numbers of Hum reports. At 1800 MHz i.e. one of the frequencies associated with 3G mobile technology it would seem to be the cochlea alone that is capable of resonance absorption, it does not even matter if it behaves dielectrically as though it were wound or unwound, there is still the condition for half wave or odd multiple half wave resonance to occur. At 2100 MHz there is probably insufficient wave penetration depth to achieve any sort of whole skull resonance and no other resonance conditions in any parts of the ear are seen. At 2400 MHz, associated with WIFI and 4G mobile technology the bone of the cochlea could act as a dielectric resonator under appropriate conditions.

To summarise then it has been shown that under appropriate frequency conditions and for various parts of the skull and ears so called microwave hearing by thermo-acoustic means could be enhanced by antenna-like dielectric resonance in these structures. This may account for some anecdotal reports of the Hum. All common VHF and UHF broadcast frequencies have the potential to contribute to these effects to a greater or lesser extent as indeed do frequencies associated with mobile phone technology with the exception of 2100 MHz. Strangely, TETRA the most controversial communication system of all seems at least theoretically from above to have the least ability to be associated with dielectric resonance enhanced microwave hearing.

Personal experience of the author

As reported elsewhere both the author and his wife a Hummers i.e. often but no always plagued by the Hum (refs). The author has noticed that his own personal Hum changed significantly when analogue UHF TV broadcasting in his home area switched off. Prior to switch off analogue broadcasting would have used vestigial sideband a form of amplitude modulation. The author would describe his Hum as quasi –periodic almost musical or Morse code- like in nature and feels the main contributing factor being demodulated was the 25 Hz frame frequency. Now it is just a more distant yet still pulsing and the pulses appear to have a very fast rise time. Another thing has also changed. Previously when the Hum was really intense, the author could only screen it out by using a smooth sheet of metallised plastic pressed as to seal the external ear flap to the scalp. Ear plugs of any kind were relatively ineffective. Now it can be screened out using a wax earplug not rolled into a taper in the traditional sense so as to plug the entire depth of the ear canal but more configured as a stub taking particular care to seal onto the skin at the outer opening of the ear canal. The author has previously shown the Hum at his address to depend on the presence of very weak acoustic sound and infrasound (ref), either from mains harmonics and sub harmonics or in the form of air and ground borne vibrations from the Dinorwig Pumped Storage Hydro-plant (ref). Yet the author has also considered the Hum to be a complex and truly Electro-acoustic effect (ref). In the light of the above perhaps we have to favour the latter consideration. TV frame frequencies are mains synchronized and this would explain the very coherent and pervasive nature of the Hum if the aforesaid were being demodulated and beating with particularly infrasonic sub-harmonics. The other alternative is that the author’s Hum was arising as a combination of the 600 MHz UHF TV frequency and 930 MHz mobile phone frequency. This would account for the need to screen the outer ear completely at 600 MHz but not at 930 MHz where it suffices simply to change impedance of the ear canal. Perhaps we also have to consider if all the sound and infrasound observed is of external origin or alternatively if thermo-acoustic demodulation can actually cause the head and/or hearing apparatus to radiate sound and infrasound into a room (ref). It is known for instance that subjects with severe tinnitus sometimes radiate acoustic energy (ref).

Conclusions

It has been shown that under appropriate frequency conditions and for various parts of the skull and ears so called microwave hearing by thermo-acoustic means could be enhanced by antenna-like dielectric resonance in these structures. This may account for some anecdotal reports of the Hum at power levels or SAR values equal to or lower than those classed as hazardous by the NRPB. In persons very badly affected by a Hum of obviously electromagnetic origin it could be merely a sad genetic disposition that they posses a skull and ear shape wherein absolutely all components of the electromagnetic hearing apparatus as defined above are at optimal dielectric resonance for one of the commonly used frequencies described. The Hum remains an enigmatic phenomenon and it needs to be properly understood that it is worthy of investigation by other great scientists in addition than by myself and should not be confided to the realms of Internet Forums where sadly serious research often gets denigrated by charlatans and crack pots.

Acknowledgments

I would like to gratefully acknowledge my wife Gwyneth for valuable discussions in this work and my old friend Professor Cyril Smith for further valuable discussions. I also acknowledge my son Dwain for assisting in experiments and anatomical measurements.