Radio Radiation Research Articles

Radio thermal emission from Pluto and Charon during the New Horizons encounter

One component of the REX instrument on NASA's New Horizons spacecraft was an investigation of the radio continuum radiation from Pluto and Charon during the flyby on 14 July 2015. The planetary thermal emission was recorded at a wavelength of 4.17 cm (7.18 GHz) during approach, departure, and specifically on the non-illuminated hemispheres of Pluto and Charon during the respective intervals between occultation ingress and egress. We derive the brightness temperatures for these disk-resolved and unresolved observations. The mean values and 1σ deviations of brightness temperature for the unresolved sunlit disk are 33.2 ± 1.4 K and 47.2 ± 5.3 K for Pluto and Charon, respectively, consistent with the global albedos of the two bodies as well as with previous ground-based estimates at smaller wavelengths. A slightly colder temperature of 29.0 ± 2.5 K was determined for the disk-integrated nightside of Pluto and a larger drop in temperature was observed for Charon (40.9 ± 0.9 K), implying a smaller thermal inertia for Charon than Pluto. The measured brightness temperature of Pluto across the nightside diametric scan reached a maximum of 29.0 ± 1.5 K in the center of the disk. The profile shape is attributed to an emissivity effect, which favors thermal emission toward higher elevation angles. As a first approximation, the effective emissivity for thermal emission is calculated for the case when Pluto and Charon are uniformly smooth homogenous spheres. Under this assumption, the effective emissivity for these observations is close to unity for all probable surface constituents, implying that the effective temperature of the Pluto subsurface is only a few percent higher than the observed brightness temperature. A considerably lower subsurface emissivity is implied, however, if the higher atmospheric temperatures near the surface determined from the REX occultation measurements are also valid for the subsurface.

Investigation of RF Originated ‘Cold’ Plasma Parameters in Capacitive Coupled Reactor

We describe a capacitive coupled plasma reactor, where the inert gas molecules are ionized by the radio frequency radiation. The control and measurement system of electrical and optical parameters of the plasma are considered. A qualitative assessment is given of the energy distribution of charge carriers.

Selective Excitation of the Microwave Sommerfeld—Zenneck Surface Wave on a Conductive Strip

Surface electromagnetic waves (SEWs) on imperfect conductors proposed by A. Sommerfeld and J. Zenneck in the early 20th century have remained unrecognized by academic science for almost a hundred years due to a regrettable misunderstanding of theorists and unsolved radio communication problems. Recognition could have come much earlier if radiophysicists had been able to apply excitation of SEWs in the centimeter range of microwaves, generation of which became possible in the first half of the 20th century with development of radar. Radiophysical experiments on excitation of surface electromagnetic waves on conductors in the centimeter range of radio waves are presented. A method for selective excitation of SEWs is described. Its essence is that the space radio wave radiation is suppressed by screening while the SEW on the conductive strip is excited by isolated currents launched through a slit in the screen.

Shock Wave Generated Megahertz Radiation of Atmosphere

Based on intuitive reasoning and a simple mathematical model, it is shown that the radio frequency electromagnetic radiation in 1-2-MHz range is generated during the propagation of a directed strong shock wave in air. It is due to the radiation from free electrons (which are produced by the shock wave) in the magnetic field of the earth. The possibility of detection of this radiation is discussed.

Distinguishing between statistical and systematic errors in quantum process tomography

It is generally assumed that every process in quantum physics can be described mathematically by a completely positive map. However, experimentally reconstructed processes are not necessarily completely positive due to statistical or systematic errors. In this paper, we introduce a test for discriminating statistical from systematic errors which is necessary to interpret experimentally reconstructed, non-completely positive maps. We demonstrate the significance of the test using several examples given by experiments and simulations. In particular, we demonstrate experimentally how an initial correlation between the system to be measured and its environment leads to an experimentally reconstructed map with negative eigenvalues. These experiments are carried out using atomic 171Yb+ ions confined in a linear Paul trap, addressed and coherently manipulated by radio frequency radiation.

An analytic description of the radio emission of air showers based on its emission mechanisms

The spatial signal distribution of the radio frequency radiation from extensive air showers on the ground contains information on crucial cosmic-ray properties, such as energy and mass. A long-standing challenge to access this information experimentally with a sparse grid of antennas is an analytic modeling of the radio signal distribution, which will be addressed in this contribution. We present an analytic model based on the two physical processes generating radio emission in air showers: the geomagnetic and the charge-excess emission. Our study is based on full Monte-Carlo simulations with the CoREAS code. Besides an improved theoretical understanding of radio emission, our model describes the radio signal distribution with unprecedented precision. Our model explicitly includes polarization information, which basically doubles the information that is used from a single radio station. The model depends only on the definition of the shower axis and on the parameters energy and distance to the emission region, where the distance to the emission region has a direct relation to the cosmic-ray mass. The model describes the true signal distribution precisely such that the model uncertainties are negligible compared to typical experimental uncertainties.

The Use of Luminos Bacteria Photobacterium phosphoreum as a Bioindicator of Geomagnetic Activity

Background. An actual problem is determination of features of different micro-organisms for the activity bioindication of environment geophysical parameter state.Objective. The aim of the paper is to determine correlation dependences between values of luminescence intensity of bacteria Photobacterium phosphoreum and factors determining geomagnetic activity.Methods. The optimum parameters of suspension were determined for research of bioluminescence intensity as a bioindicator of the geomagnetic field state. The monitoring of specific intensity of bacteria luminescence has been carried out for 2 months and it was compared to the daily values of activity of the geomagnetic field in the conditions of Kiev, during the research of bioluminescence. Vari­ation determination of the geomagnetic field was conducted from data of Space Environment Center, NOAA & U.S. Air Force. Description of sun activity was conducted with the use of the Wolf numbers and flux of sun radio radiation at a wavelength 10,7 сm.Results. The correlation coefficients of changes of bacteria bioluminescence intensity daily values were calculated and compared to the K-index and Ap-index values, Wolf numbers, and flux of sun radio radiation. The inverse proportional reliable average correlation was defined R = -0,41 between the values of specific bacterial luminescence and the K-indexes of the geomagnetical field, and with the values of flux of sun radio radiation – reliable directly proportional correlation. It is shown, that at the geomagnetic field variation intensity increase there is reduction of values of bacteria bioluminescence specific intensity.Conclusions. The presence of reliable inverse dependence between K-indexes of geomagnetic field is shown and specific intensity of the P. rhosphoreum luminescence, the correlation coefficient in months with increased geomagnetic activity was R = -0,51. The use of the automated system of the luminescent bacteria luminescence intensity monitoring allows better forecasting in time the manifestations of indignations of the Earth’s magnetic field.

Implementation of a wireless charging system for mobile devices

This work describes the implementation of an RF based wireless charging system using RF transmitting and receiving modules. The objective of this work is to implement a system that has the ability to interact and communicate wirelessly within short range. This mobile wireless charging switching system consists of two sections, the transmitting and the receiving section. Each section was interfaced to 433MHz transmitting and receiving modules. The transmitter section of the wireless mobile charging system sends bursts of 433MHz signal through push button switch which is used in the initiation of the charging process to the receiver; when this signal is received by the receiver, it activates a relay which in turn switches on the internal power that comprises the backup battery, DC-to DC converter via a Universal Serial Bus (USB) port to the mobile device to begin charging. This work was able to achieve a wireless transfer of power for distance of about one metre between the transmitter and the receiver.Keywords: wireless charging, radio frequency radiation, electromagnetic induction, inductive coupling, microcontroller,

Precision apiculture: Development of a wireless sensor network for honeybee hives

Wireless in-hive sensor networks show promise in apiary management and research. However, radio frequency electromagnetic radiation (RF-EMR) emitted by wireless technologies could affect honeybees at the individual and the colony level. Prior research has noted that different operation frequencies and power of transferred signals affect insect and larger animal behavior. An on-line wireless sensor network was developed that continuously monitored in-hive temperature, relative humidity, and acoustics. While testing the network performance, a wired version of the developed sensor network was used to substantiate whether or not RF-EMR from Wi-Fi affects the measured parameters through a 30-day study in 2015. Two groups of three beehives were monitored: the first group was subjected to 2.4 GHz Wi-Fi signal while the second group was located outside of radio communication range. During RF-EMR exposure, in-hive temperature increased by an average of 0.09C and relative humidity increased by 1.53%, sound increased in amplitude by 0.03 dB but decreased in frequency by 2.57 Hz. All measured parameters had a higher standard deviation (SD) during the exposure treatment as compared to these changes during RF-EMR exposure, thus differences were not significant at the p < 0.05 level However, Control hive 1 swarmed 2 months before the start of the experiment and was on average 14.4% less humid and 1.57 dB quieter than the other monitored. Based on this research, no evidence of beehive environment change in response to RM-EMR was found. At the same time, the observation of abnormally measured parameters could be linked with a stressed colony (due to a swarming event), which might help apiculturists reduce production losses by rapidly reacting to the observed indicators of potential stress. Given the complexity of beehive dynamics, research on other potential effects of RF-EMR is needed before adopting wireless technologies in beehive sensors.

Contributions of dark matter annihilation to the global 21 cm spectrum observed by the EDGES experiment

The EDGES experiment has observed an absorption feature in the global 21 cm spectrum with a surprisingly large amplitude. These results can be explained by decreasing the kinetic temperature of baryons, which could be achieved through the scattering between the baryons and cold dark matter particles. It seems that the most researched dark matter annihilation model is not able to explain such a large amplitude, since the interactions between the particles produced by the dark matter annihilation and the particles that have been present in the Universe could increase the baryonic temperature. Recently, C. Feng and G. Holder have suggested that the large amplitude in the global 21 cm spectrum could be produced by considering the possible excess of the early radio radiation. In this paper, we propose that the dark matter annihilation still works to explain the large amplitude observed by the EDGES experiment. Even including the dark matter annihilation, the large absorption amplitude in the global 21 cm spectrum can be produced by considering the possible excess of the early radio radiation.

Toxicology and carcinogenesis studies in Sprague Dawley (Hsd:Sprague Dawley SD) rats exposed to whole-body radio frequency radiation at a frequency (900 MHz) and modulations (GSM and CDMA) used by cell phones.

The predominant source of human exposure to radio frequency radiation (RFR) occurs through usage of cellular phone handsets. The Food and Drug Administration nominated cell phone RFR emission for toxicology and carcinogenicity testing in 1999. At that time, animal experiments were deemed crucial because meaningful human exposure health data from epidemiological studies were not available. Male and female Sprague Dawley (Hsd:Sprague Dawley SD) rats were exposed to time-averaged whole-body specific absorption rates of Global System for Mobile Communications (GSM)- or Code Division Multiple Access (CDMA)-modulated cell phone RFR at 900 MHz in utero, during lactation, and after weaning for 28 days or 2 years. Genetic toxicology studies were conducted in rat peripheral blood erythrocytes and leukocytes, brain cells, and liver cells. (Abstract Abridged).

Toxicology and carcinogenesis studies in B6C3F1/N mice exposed to whole-body radio frequency radiation at a frequency (1,900 MHz) and modulations (GSM and CDMA) used by cell phones.

The predominant source of human exposure to radio frequency radiation (RFR) occurs through usage of cellular phone handsets. The Food and Drug Administration nominated cell phone RFR emission for toxicology and carcinogenicity testing in 1999. At that time, animal experiments were deemed crucial because meaningful human exposure health data from epidemiological studies were not available. Male and female B6C3F1/N mice were exposed to time-averaged whole-body specific absorption rates of 0 (sham control), 5, 10, or 15 W/kg Global System for Mobile Communications (GSM)- or Code Division Multiple Access (CDMA)-modulated cell phone RFR at 1,900 MHz for 28 days or 0, 2.5, 5, or 10 W/kg GSM- or CDMA-modulated cell phone RFR for up to 2 years. Genetic toxicology studies were conducted in mouse peripheral blood erythrocytes and leukocytes, brain cells, and liver cells. (Abstract Abridged).

S–PASS view of polarized Galactic synchrotron at 2.3 GHz as a contaminant to CMB observations

We have analyzed the southern sky emission in linear polarization at 2.3 GHz as observed by the S -band Polarization All Sky Survey (S-PASS). Our purpose is to study the properties of the diffuse Galactic polarized synchrotron as a contaminant to B-mode observations of the cosmic microwave background (CMB) polarization. We studied the angular distribution of the S-PASS signal at intermediate and high Galactic latitudes by means of the polarization angular power spectra. The power spectra, computed in the multipole interval 20 ≤ ℓ ≤ 1000, show a decay of the spectral amplitude as a function of multipole for ℓ ≲ 200, typical of the diffuse emission. At smaller angular scales, power spectra are dominated by the radio point source radiation. We find that, at low multipoles, spectra can be approximated by a power law CℓEE,BB ∝ ℓα, with α ≃ −3, and characterized by a B-to-E ratio of about 0.5. We measured the polarized synchrotron spectral energy distribution (SED) in harmonic space, by combining S-PASS power spectra with low frequency WMAP and Planck ones, and by fitting their frequency dependence in six multipole bins, in the range 20 ≤ ℓ ≤ 140. Results show that the recovered SED, in the frequency range 2.3–33 GHz, is compatible with a power law with βs = −3.22 ± 0.08, which appears to be constant over the considered multipole range and in the different Galactic cuts. Combining the S-PASS total polarized intensity maps with those coming from WMAP and Planck we derived a map of the synchrotron spectral index βs at angular resolution of 2° on about 30% of the sky. The recovered βs distribution peaks at the value around −3.2. It exibits an angular power spectrum which can be approximated with a power law Cℓ ∝ ℓγ with γ ≃ −2.6. We also measured a significant spatial correlation between synchrotron and thermal dust signals, as traced by the Planck 353 GHz channel. This correlation reaches about 40% on the larger angular scales, decaying considerably at the degree scales. Finally, we used the S-PASS maps to assess the polarized synchrotron contamination to CMB observations of the B-modes at higher frequencies. We divided the sky in small patches (with fsky ≃ 1%) and find that, at 90 GHz, the minimal contamination, in the cleanest regions of the sky, is at the level of an equivalent tensor-to-scalar ratio rsynch ≃ 10−3. Moreover, by combining S-PASS data with Planck 353 GHz observations, we recover a map of the minimum level of total polarized foreground contamination to B-modes, finding that there is no region of the sky, at any frequency, where this contamination lies below equivalent tenor-to-scalar ratio rFG ≃ 10−3. This result confirms the importance of observing both high and low frequency foregrounds in CMB B-mode measurements.

ALMA Observations of Supernova Remnant N49 in the LMC. I. Discovery of CO Clumps Associated with X-Ray and Radio Continuum Shells

Abstract N49 (LHA 120-N49) is a bright X-ray supernova remnant (SNR) in the Large Magellanic Cloud. We present new 12CO (J = 1–0, 3–2), H i, and 1.4 GHz radio continuum observations of the SNR N49 using Mopra, ASTE, ALMA, and ATCA. We have newly identified three H i clouds using ATCA with an angular resolution of ∼20″: one associated with the SNR and the others located in front of the SNR. Both the CO and H i clouds in the velocity range from 281 to 291 km s−1 are spatially correlated with both the soft X-rays (0.2–1.2 keV) and the hard X-rays (2.0–7.0 keV) of N49 on a ∼10 pc scale. CO 3–2/1–0 intensity ratios indicate higher values of the CO cloud toward the SNR shell with an angular resolution of ∼45″, and thus a strong interaction was suggested. Using the ALMA, we have spatially resolved CO clumps embedded within or along the southeastern rim of N49 with an angular resolution of ∼3″. Three of the CO clumps are rim brightened on a 0.7–2 pc scale in both hard X-rays and the radio continuum: this provides further evidence for dynamical interactions between the CO clumps and the SNR shock wave. The enhancement of the radio synchrotron radiation can be understood in terms of magnetic field amplification around the CO clumps via a shock–cloud interaction. We also present a possible scenario in which the recombining plasma that dominates the hard X-rays from N49 was formed via thermal conduction between the SNR shock waves and the cold/dense molecular clumps.

The TAIGA Experiment: From Cosmic Ray Physics to Gamma Astronomy in the Tunka Valley

The article presents the relevance and advantages of the new gamma observatory TAIGA (Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy), which is being constructed in the Tunka Valley 50 km from Lake Baikal. Various detectors of the six TAIGA gamma observatory arrays register the Cherenkov and radio radiation, as well as the electron and muon components of EAS. The primary objective of the TAIGA gamma observatory is to study the high-energy part of the gamma-ray spectrum, in particular, in order to search for Galactic PeVatrons. The energy, direction, and position of the EAS axis are reconstructed in the observatory based on the data of the wide-angle Cherenkov detectors of the TAIGA-HiSCORE experiment. Taking into account this information, the gamma quanta are distinguished from the hadron background using the data obtained by the muon detectors and telescopes that register the EAS image in the Cherenkov light. In this hybrid mode of operation, the atmospheric Cherenkov telescopes can operate in the mono-mode, and the distance between them can be increased to 800–1000 m, which makes it possible to construct an array with an area of 5 km2 and more at relatively low cost and in a short time. By 2019, the first stage of the gamma observatory with an area of 1 km2 will be constructed; its expected integral sensitivity for detecting the gamma radiation with an energy of 100 TeV at observation of the source for 300 hours will be approximately $$2 \times 5$$ 10–13 TeV cm–2s–1.

THE ANALYSIS OF EXPERT SYSTEM FOR ADAPTING DECISIONS FOR DETERMINING THE TYPE OF RADIO RESPONSE SOURCES

In this article, the authors of research described the sources of radio radiation and explained the complexity of identifying sources of radioelectronic radiation under a priori uncertainty. Authors of the article state, that the source of radio-electron radiation can be identified by a set of parameters of its signal. It is established that the informational nature of the signal source of radio emission for the devices of radio monitoring depends on how reliable this signal is detected and how accurately (precisely) its parameters are determined, which are useful days of radio monitoring of the message or value. Because signal tracking always takes place against a background of different kinds of interference, the fact of detecting a signal, as well as errors in measuring signal parameters and selecting messages are always random. The problem of determining the type of signal, and therefore the source, which it emits, is partially solved by the preliminary analysis of the ether on the hearing conducted by the operators of radiomonitoring. This makes it possible not to distract from non-informative signals belonging to sources of radio-electronic radiation that are not showing interest to radio monitoring, to shorten the search time for sources of radio-electronic radiation and to minimize the cost of depreciation of equipment. The disadvantage of this method is the necessity to have a sufficient number of trained operators and to constantly increase their training. Was given that the preparation of one operator to a professional level can last 6-12 months, it is very difficult to provide data requirements. Therefore, in the given article it is suggested to analyze the parameters of sources of radio-electronic radiation on a set of parameters of sources signals of radio-electron radiation with the help of expert decision support system concerning determination of sources parameters of radio-electronic radiation. In the article, the authors proposed an expert system for determining the parameters of sources of radio-electronic radiation using a database management system. Unlike machine programs that use procedural analysis, expert systems solve problems in a narrow subject area (specific field of expertise) based on deductive considerations. Such systems are often able to find solutions that are unstructured and poorly defined. They cope with the lack of structuring by involving heuristics, that is, the rules described in accordance with the experience of using the equipment, which may be useful in those situations where the lack of necessary knowledge or time eliminates the possibility of complete analysis.

Математична модель функціонування органів радіолокаційної розвідки РВіА

The experience of modern wars and military exercises testifies that 70-75% of the total volume of enemy fire destruction tasks in the operation is assigned to missile forces and artillery (MFA), and in the conditions of conducting an antiterrorist operation in the territories of Donetsk and Lugansk regions (ATO) this the indicator reached 90-95%. The fulfillment of such a large volume of fire missions depends on the effectiveness of combat support for the combat operations of the MFA.Intelligence information is obtained by performing reconnaissance missions, for which reconnaissance units are created from the artillery reconnaissance (AR) units and additional forces and assets.The experience of the use of reconnaissance units in the ATO testifies that the greatest losses were incurred by the means of radar reconnaissance (RR), which were detected by radio electronic radiation with the means of electronic reconnaissance of the enemy. This led to constant bombardment of the positions of the radar with enemy artillery and to the cases of their defeat.One way to increase the survivability of the means of RR is to reduce the time of radio electronic radiation while conducting reconnaissance and maneuvering between positions.Thus, in the practice of using the means of RR, a contradiction arose between the requirement to improve the quality of reconnaissance information about enemy facilities in the interests of their fire damage to the MFA and the requirement to ensure the required level of survivability of the means of RR. Time of electronic radiation, on the one hand, should be increased to ensure the quality of information, and, on the other hand, it should be reduced to ensure survivability.The purpose of the article is to improve the model of the operation of RR tools, which will enable to determine the values of their operation indicators for further substantiation of recommendations on the order of conducting reconnaissance with ensuring the required survivability index.The existing model has been further developed by including in the graph of functional states of the means of RR: the most probable conditions for the stay of the means of RR in obtaining reconnaissance information about enemy targets; transition from the state “under the fire influence of the enemy” to the “change position” state. This transition describes the process of implementing the release of the means of RR from under the enemy's fire to ensure vitality and create more favorable conditions for further reconnaissance.The model of the operation of the RR facilities makes it possible to determine the indices of the process of their functioning in the conditions of combat operations and in the future to justify recommendations on the order of conducting reconnaissance in order to increase their survivability.

SRY gene mutation in Rattus norvegicus induced by various time exposure of mobile phone

Amir A, Darwin E, Juniarto AZ. 2018. Effects of mobile phone exposure to SRY gene in Rattus norvegicus. Biodiversitas 19: 802-808. Mobile phones are low power radio devices, which transmit and receive radio frequency radiation in the microwave spectrum ranging from 900-1,800 MHz through an antenna used closely to the user’s head. Radiation destructs living tissue by altering structure of cell and damaging the DNA, damaging of genetic material in reproductive cells causes mutations and affecting to the next generation. The genetic database of mutation in human SRY gene has been collected and had the correlation between mutation and the occurrence of sex development disorder (translocation). However, the study focussing on SRY gene mutation to the exposure of mobile phone has not been studied, yet. This study was aimed to investigate the effect of various time exposure of mobile phone toward the characteristic of SRY gene fragments in Rattus norvegicus. Experimental research with randomized post test only control design was conducted on 20 Wistar aged 2-3 months with 200-250 grams of weight. Samples were divided into four groups, with three treatment groups based on radiation exposure time (30, 60, and 90 minutes), and one group as control group (without treatment) for 60 days. Following exposure, DNA was isolated from blood of rat, and amplified with a pair of SRY primer set. Positive DNA of SRY gene was assessed by sequencing the genes and determining the mutations. There were three single nucleotide polymorphism (SNP) of SRY gene in histidine 38 glutamine, (CAT&gt; CAG), proline 76 threonine (CCT &gt;ACT) and leucine 102 leucine (CTG &gt;TTG). Long duration of radiation exposure for 90 minutes increased the risk of SRY gene mutation.

Analysis of Accuracy of Direct Digital Method of Correlative-Interferometric Direction Finding with Two-Dimensional Correlative Processing of Spatial Signal

The paper investigates the accuracy of the direct digital method of correlative-interferometric direction finding with reconstruction of spatial analytical signal in the aperture of linear antenna array. The main requirements for modern means of radio direction finding are to ensure their accuracy and noise immunity and ability to work in real time with minimum hardware expenditure. The typical operating condition of the direction finding means of random source of radio radiation as a part of modern systems of radiomonitoring is the presence of a complex electromagnetic environment, which dynamically changes. The perspective trend of the realization of radio direction finding in these conditions is the use of digital correlative-interferometric direction finders. The analytical expressions for the error variance of the estimation of signal delay and direction have been received. It has been shown that in addition to the basic classic control parameters such as the number of the direction-finding channels and the time of the radiation analysis, the error variance of the direction finding is also affected by the magnitude of the spatial shift of the correlation processing, by the view of the weighting function of the spatial digital radiation pattern and by the value of the normalized autocorrelative function. During the simulation the dependence family of the middle square deviation of estimation of the direction from the signal/noise ratio for the different values of the spatial shift is obtained. The results of the simulation have coincided with the assessment of the accuracy of the direction finding, obtained analytically.

Radio frequency radiation-related cancer: assessing causation in the occupational/military setting

Background and aimWe reexamine whether radio frequency radiation (RFR) in the occupational and military settings is a human carcinogen. MethodsWe extended an analysis of an already-reported case series of patients with cancer previously exposed to whole-body prolonged RFR, mainly from communication equipment and radar. We focused on hematolymphatic (HL) cancers. We used analysis by percentage frequency (PF) of a cancer type, which is the proportion of a specific cancer type relative to the total number of cancer cases. We also examined and analyzed the published data on three other cohort studies from similar military settings from different countries. ResultsThe PF of HL cancers in the case series was very high, at 40% with only 23% expected for the series age and gender profile, confidence interval CI95%: 26–56%, p<0.01, 19 out of 47 patients had HL cancers. We also found high PF for multiple primaries. As for the three other cohort studies: In the Polish military sector, the PF of HL cancers was 36% in the exposed population as compared to 12% in the unexposed population, p<0.001. In a small group of employees exposed to RFR in Israeli defense industry, the PF of HL cancers was 60% versus 17% expected for the group age and gender profile, p<0.05. In Belgian radar battalions the HL PF was 8.3% versus 1.4% in the control battalions as shown in a causes of deaths study and HL cancer mortality rate ratio was 7.2 and statistically significant. Similar findings were reported on radio amateurs and Korean war technicians. Elevated risk ratios were previously reported in most of the above studies. ConclusionsThe consistent association of RFR and highly elevated HL cancer risk in the four groups spread over three countries, operating different RFR equipment types and analyzed by different research protocols, suggests a cause-effect relationship between RFR and HL cancers in military/occupational settings. While complete measurements of RFR exposures were not available and rough exposure assessments from patients interviews and from partial exposure data were used instead, we have demonstrated increased HL cancers in occupational groups with relatively high RFR exposures. Our findings, combined with other studies, indicate that exposures incurred in the military settings evaluated here significantly increased the risk of HL cancers. Accordingly, the RFR military exposures in these occupations should be substantially reduced and further efforts should be undertaken to monitor and measure those exposures and to follow cohorts exposed to RFR for cancers and other health effects. Overall, the epidemiological studies on excess risk for HL and other cancers together with brain tumors in cellphone users and experimental studies on RFR and carcinogenicity make a coherent case for a cause-effect relationship and classifying RFR exposure as a human carcinogen (IARC group 1).