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Question #: 270

Question: WHAT EFFECTS OF CELL PHONES WILL THERE BE ON YOUNGER PEOPLE OPPOSED TO OLDER PEOPLE? THE AGE OR STATE DEVELOPMENT EFFECT DANGERS A PHONE?

Current Solution

Physical size of the subject affects the fraction of the total radiofrequency energy that is absorbed in the body. To account for this known effect, the maximum permissible exposure standards for radiofrequency energy were set for the worst-case condition, that is assuming the body size for maximal absorption at a given frequency. Thus the maximum permissible exposure standards are fully protective for bodies of different sizes. For more detailed information, see the answers and the cited references to questions 79, 109, 694, and 893 under the Nonionizing Radiation section of the Health Physics Society Ask The Expert Web page. Gary H. Zeman, ScD, CHP

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Other Possible Solutions to this Question

  • I WOULD LIKE TO INQUIRE ABOUT THE PHYSICS PRINCIPLES REGARDING USE OF MOBILE PHONES AND DEVELOPMENT BRAIN TUMORS. I'VE BEEN THROUGH MANY SITES BUT THEY CAN NEVER GIVE AN EXACT ANSWER. REALLY SOMEONE TUMORS OR DOES IT HAVE DO WITH INTENSITY RADIATION DISTANCE BETWEEN PHONE INDIVIDUAL?

    It is not clear that mobile phones do produce brain tumors, or any serious health effects for that matter. A number of epidemiology studies have been almost completely negative on the issue.

    See the article I wrote with John Moulder in IEEE Spectrum magazine and also Moulder's FAQ on mobile phones and health.

    There has been a lot of discussion over the years about the possible mechanisms by which microwave energy such as emitted by cell phones might produce biological effects. The one unequivocal mechanism is the heating of tissue, but mobile phones operate at power levels that are too low to cause noticeable heating in the user. Scientists have speculated about other mechanisms, but these theories remain unproven and many of them have been challenged on biophysical grounds.

    Whatever may be the risks or nonrisks of mobile phone radiation, a hands-free kit is an effective way for the user to reduce his or her exposure to radiofrequency energy while using a mobile phone.

    Kenneth R. Foster, Professor
    Department of Bioengineering
    University of Pennsylvania

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    I WOULD LIKE TO INQUIRE ABOUT THE PHYSICS PRINCIPLES REGARDING USE OF MOBILE PHONES AND DEVELOPMENT BRAIN TUMORS. I'VE BEEN THROUGH MANY SITES BUT THEY CAN NEVER GIVE AN EXACT ANSWER. REALLY SOMEONE TUMORS OR DOES IT HAVE DO WITH INTENSITY RADIATION DISTANCE BETWEEN PHONE INDIVIDUAL?

  • HOW MUCH RADIATION GIVEN OFF BY A CELL PHONE AND THERE ANY WAY TO STOP THE FROM BEING ABSORBED INTO YOURSELF?

    Portable cell phones emit about 0.6 watts of radiofrequency energy, limited primarily by the power of the battery. As with any radiofrequency transmitter, there will be some amount of absorption in the human body; the amount depends on how close you are to the antenna. The Federal Communications Commission (FCC) limits the amount of radiofrequency energy which cell phones can deposit in the body to levels at which no health effects are to be expected. See an article on Cell Phone Safety on this website for more information.

    Gary H. Zeman, ScD, CHP

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    HOW MUCH RADIATION GIVEN OFF BY A CELL PHONE AND THERE ANY WAY TO STOP THE FROM BEING ABSORBED INTO YOURSELF?

  • HOSPITALS DO NOT ALLOW CELL PHONE USE DUE TO POTENTIAL INTERFERENCE. LAST WEEKEND I WAS IN A HOSPITAL WHERE THE TOP OF BUILDING STUDDED WITH TOWER ANTENNAS. WHY IT THAT PHONES WOULD CAUSE INTERFERENCE, BUT ANTENNAS NOT?

    It's a question of signal strength. Interference has been observed only very close to transmitting antennas where there is strong signal strength. Interference has been observed in some medical electronics due to hand-held cell phones. Roof-top antennas are some distance away from any susceptible electronics. In addition to proximity, the directionality of the antennas is important. Most rooftop antennas have strong gain in the forward direction—towards the horizon—and very low gain in the vertical direction. Finally, there are layers of building materials shielding the interior areas from the rooftop antennas. Proximity, directionality, shielding—all go towards reducing the signal strength inside a building due to the antennas on the roof so that interference is not generally an issue. This does not mean that you cannot receive the signals from the roof top antennas inside the building; it simply means that the received signals are not strong enough to cause interference. Gary H. Zeman, ScD, CHP

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    HOSPITALS DO NOT ALLOW CELL PHONE USE DUE TO POTENTIAL INTERFERENCE. LAST WEEKEND I WAS IN A HOSPITAL WHERE THE TOP OF BUILDING STUDDED WITH TOWER ANTENNAS. WHY IT THAT PHONES WOULD CAUSE INTERFERENCE, BUT ANTENNAS NOT?

  • WE ARE ALWAYS CONCERNED THAT THERE WON'T BE ENOUGH VACCINE TO VACCINATE OUR PATIENTS IN THE FALL. WHAT CAN DO ASSURED WE'VE DONE ALL POSSIBLY AVOID THIS TYPE OF SITUATION?

    It is never too early to begin planning for the coming fall's influenza vaccination program. The most important thing you can do initially is to place your order for vaccine from your usual source. Some manufacturers often stop taking pre-orders in mid-May. Be sure to include vaccine for pediatric patients needing two doses and also for your facility's healthcare workers as part of your overall campaign.

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    WE ARE ALWAYS CONCERNED THAT THERE WON'T BE ENOUGH VACCINE TO VACCINATE OUR PATIENTS IN THE FALL. WHAT CAN DO ASSURED WE'VE DONE ALL POSSIBLY AVOID THIS TYPE OF SITUATION?

  • THERE´S A CELLULAR PHONE ANTENNA ON THE ROOF OF BUILDING RIGHT OPPOSITE MY WINDOW, LEVEL ABOUT TEN METERS ABOVE HEAD. AM I LIKELY TO BE IN RADIUS RADIATION?

    You will have to contact the cell phone company that operates that particular antenna to obtain the radiation pattern (or emission pattern) of that particular type of antenna. Different models of antennae have different emission patterns to provide coverage of different size and shape geographical areas. For example, many of the antennae are directional, only broadcasting in the forward direction. Most emit very little radiation in the upward and downward directions, although the vertical extent of the beam can be quite different for different antennas. Some are strongly focussed on the horizon, others provide better coverage of nearby areas. Many antennae only broadcasting into a defined geometrical sector of the horizion, often 120 degrees so that three sets of antennae are required to cover the entire horizon. Therefore, to find the type of radiation pattern broadcast by any particular antenna will require local information from the equipment operator. Gary Zeman, ScD

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    THERE´S A CELLULAR PHONE ANTENNA ON THE ROOF OF BUILDING RIGHT OPPOSITE MY WINDOW, LEVEL ABOUT TEN METERS ABOVE HEAD. AM I LIKELY TO BE IN RADIUS RADIATION?

  • I BOUGHT YOUR BOOK AND WAS HOPEING IT HAD PLANS OR DIMENTIONS ON HOW TO BUILD A CNC HOLD 4X8 SHEET OF PLY. WILL THE IN SCALE UP?

    BYCNC Response:
    The book build was intended to be 20 inches x 40 inches. Larger machines were designed after the book build was introduced so customers would have the option to go bigger than what the book offered. Check out our larger machines on the website as the machines sizes range from 1 foot x 3 feet all the way up to 6 feet x 12+ feet.

    User Response:
    I'm not wanting to spend $3,000+ on a machine, I want to build one that will do a 4x8 sheet of wood. Will the plans in the book scale up?

    BYCNC Response:
    It is possible to scale the book build up, but the rigidity of the gantry would be questionable at that span, even if the height of the gantry structure were to be increased. The gantry design would need to be modified to become a box shape rather than a flat configuration. The kits on the site were design for those wanting a larger machine.

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    I BOUGHT YOUR BOOK AND WAS HOPEING IT HAD PLANS OR DIMENTIONS ON HOW TO BUILD A CNC HOLD 4X8 SHEET OF PLY. WILL THE IN SCALE UP?

  • What are the specs for the stepper motors on the Bluechick? How much for shipping to Toronto, ON, Canada? Is there duty for shipping to Canada?

    Here is the answer to your first questions regarding the blueChick motors:
    https://buildyourcnc.com/FAQ/9024

    The shipping of the blueChick CNC will depend on if the machine is assembled or not. There is a duty for international orders, but I am unsure of the cost in other countries other than the US.

    Thanks

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    What are the specs for the stepper motors on the Bluechick? How much for shipping to Toronto, ON, Canada? Is there duty for shipping to Canada?

  • I NEED HELP IN GATHERING PUBLISHED INFORMATION ABOUT THE RISKS POSED BY CELL TOWERS PLACED ON SCHOOL GROUNDS. THERE WHICH WOULD ENABLE ME TO GATHER/CALCULATE OR MEASURE RADIATION SPECIFIC SITE?

    The best single reference is the Federal Communications Commission (FCC) Website. Look for:
    Bulletin 56, "Questions and Answers about Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Fields,"

    Bulletin 65, "Evaluating Compliance With FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields,"

    "A Local Government Official's Guide to Transmitting Antenna RF Emission Safety: Rules, Procedures, and Practical Guidance."
    An excellent technical paper with field measurements of cell-tower emissions was published by R.C. Petersen and P.A. Testagrossa in the journal Bioelectromagnetics, volume 13, page 527ff, 1992. If you need onsite technical support and services there are various consultants available, such as Richard Tell Associates, Inc. Gary Zeman, ScD, CHP Lawrence Berkeley National Laboratory

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    I NEED HELP IN GATHERING PUBLISHED INFORMATION ABOUT THE RISKS POSED BY CELL TOWERS PLACED ON SCHOOL GROUNDS. THERE WHICH WOULD ENABLE ME TO GATHER/CALCULATE OR MEASURE RADIATION SPECIFIC SITE?

  • COULD YOU PLEASE EXPLAIN, IF IT'S TRUE, THAT HANDS-FREE CELL PHONE CAR MICROPHONES RADIATE MORE THAN ANY OTHER INSTRUMENT USED WITH THESE PHONES?

    Hands-free cell phone car microphones have been tested by the manufacturers and meet the current ANSI/IEEE (American National Standards Institute/Institute of Electrical and Electronics Engineers) standards for radiofrequency (RF) safety. These are the same standards that the Federal Communications Commission enforces under the Telecommunications Act of 1996, and they place limits on the specific absorption rate (SAR) of RF energy in the body. Recent inflammatory articles in the British press were not substantiated by testing at ISO-accredited testing facilities at Motorola. Manufacturers of cell phones are required under FCC regulations to assure that their products meet the SAR limits on both hand-held and hands-free units. Further information can be obtained on the Internet at The Center for Devices and Radiological Health (FDA information) or Office of Engineering and Technology (FCC information).

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    COULD YOU PLEASE EXPLAIN, IF IT'S TRUE, THAT HANDS-FREE CELL PHONE CAR MICROPHONES RADIATE MORE THAN ANY OTHER INSTRUMENT USED WITH THESE PHONES?

  • Are the VFDs and pumps compatible with the european electric circuit (230V/50Hz) and what kind of connectors will be delivered?

    The VFD (Variable Frequency Drive) is not supplied with plugs, cable or connectors. You provide the cable and power plug or connector for the VFD. All you need to do is get an extension cable and expose the three wires of the cable and connect them to R, T and Ground. Please see the datasheet on this page for wiring information: https://www.buildyourcnc.com/item/spindle-inverter-2!2kw-spindle-novfd

    Our pumps only have a 110 volt input, so you will need to purchase the pump in your country.

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    Are the VFDs and pumps compatible with the european electric circuit (230V/50Hz) and what kind of connectors will be delivered?

  • WHAT ARE THE HEALTH RISKS OF LIVING NEAR A CELL PHONE TOWER?

    There is very little radiofrequency (RF) energy exposure to people inside a building from a cellular base station located on its roof. There are several reasons for this. First, the transmitters operate at low power levels. Second, the antennas are normally mounted near the edges of the roof and are aimed away from the building. Third, most cellular transmitters use "high gain" or panel antennas. Such antennas transmit most of their energy in a narrow beam (in the vertical direction) from their front surfaces, away from the building. They radiate very little energy downwards towards the roof or backwards from their rear surfaces. Finally, building materials absorb a significant fraction of the RF energy passing through them. As a result, the RF signal levels at any location inside the building are invariably low and far below safety limits. The situation might be different in some locations on the roof itself. RF signal levels close to (within a few feet) and directly in front of cellular base station antennas can easily exceed safety limits. Some precautions are needed to prevent people from walking directly in front of the antennas while they are transmitting. This applies also to paging and other systems that use rooftop antennas, some of which transmit at higher power levels than many cellular base stations. Kenneth R. Foster, Ph.D.

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    WHAT ARE THE HEALTH RISKS OF LIVING NEAR A CELL PHONE TOWER?

  • WILL IT BE HARMFUL TO USE MY MOBILE PHONE DURING PREGNANCY? IF HARMFUL, SHOULD I DISCONTINUE USING OR MODERATELY?

    Thank you for your inquiry about the risk to your embryo by using a cellular phone during pregnancy. Sometimes it is not made clear to the public that there are different kinds of radiation. The electrical fields from a cellular phone are nothing like x ray. The energy is so low in the electrical waves of cellular phones that it does not represent a risk to the developing embryo. If you use the cellular phone conventionally by placing it to your ear, you further reduce the exposure to the embryo, which is already extremely low because of the distance of the phone from your ear to your uterus. There are no studies dealing with the risks of cellular phones on the outcome of pregnancy in humans, but numerous animal studies indicate that the exposures from the phones do not represent a risk for birth defects or miscarriage. Of course you must realize that every healthy pregnant woman begins her pregnancy with a 3% risk for birth defects and a 15% risk for miscarriage. Good luck with your pregnancy.

    Robert Brent MD, PhD, DSc(Hon)

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    WILL IT BE HARMFUL TO USE MY MOBILE PHONE DURING PREGNANCY? IF HARMFUL, SHOULD I DISCONTINUE USING OR MODERATELY?

  • In the 3 Axis Electronics Combo, what is the AC input of the power supply (110v or 220v??). is it possible to specify a certain voltage when ordering?

    In our 3-Axis electronics kit, the power supply's provided are capable of both 110V-220V. You have the capability to switch between both in case you might decide to run 220v in the near future or will relocate where 110v is being used.

    Additional Information:
    Connect spindle to the board

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    In the 3 Axis Electronics Combo, what is the AC input of the power supply (110v or 220v??). is it possible to specify a certain voltage when ordering?

  • I am interested in purchasing the Green Lean complete kit and also buy the ArtCamPro what other software will I need to up and running?

    If you were to buy all of that, only thing you'll need is the mach3 software to run the machine.

    Click the link to add information to this solution:
    I am interested in purchasing the Green Lean complete kit and also buy the ArtCamPro what other software will I need to up and running?

  • WILL CELL PHONES SPARK A FIRE AT THE GAS STATION?

    I can't think of any reason that it would be dangerous. However, I checked with the Cellular Telecommunications Industry Association. The Chairman of the Association sent the following memo on 18 June 1999, to the Associations' Board of Directors and others:
    "You may have received inquiries about wireless phones causing fires or explosions at gas stations. In particular, you may have been asked about an alleged explosion at a gas station in Indonesia. We have been unable to verify any such occurrence in Indonesia or anywhere else. Moreover, in our discussions with Shell Oil they have stated they have attempted to verify these reports and also have not been able to document any such occurrence."
    Nonetheless, in an abundance of caution, some manufacturers have included language in the owner's manuals for their products that recommends wireless phone users turn off their phones while at refueling points (gas stations). In addition, we have received information that Exxon will begin issuing warning signs at all domestic gas stations advising drivers to turn off all wireless communications devices when entering Exxon gas stations.

    While wireless phone owners should always consult their owner's manual for information on the use of the phone, we are not aware of any incident that would justify these concerns."

    Gen Roessler, Editor
    HPS website

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    WILL CELL PHONES SPARK A FIRE AT THE GAS STATION?

  • What are the overall dimensions of the 2.5A small stepper drivers? Is there a CAD model available?

    The overall dimensions of our 2.5 modular stepper divers is:

    L: 1.875"/ 47.625mm
    W: 1.433"/ 36.3982mm
    H: .585"/ 14.859mm (height might change due to different terminal block height (other we have on hand is .464"/ 11.7856mm))

    Currently we do not have a CAD model on hand.

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    What are the overall dimensions of the 2.5A small stepper drivers? Is there a CAD model available?

  • Trying to cut 24, and 26 G steel sheets in various shapes. Will CO2 laser be enough? And will it cause alot of heat in the product?

    A CO2 laser will not be suitable for cutting steel. You would likely need a very powerful fiber laser to cut steel, and even then you have to take into consideration the reflective properties of steel which can pose danger to the machine.

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    Trying to cut 24, and 26 G steel sheets in various shapes. Will CO2 laser be enough? And will it cause alot of heat in the product?

  • ARE THERE PRODUCTS AVAILABLE TO THE GENERAL PUBLIC THAT CAN BE PURCHASED PROTECT CELLULAR OR PORTABLE TELEPHONE USERS FROM RADIATION? IF SO, WHERE THESE FOUND?

    There are a number of opportunistic gadgets on the market to allegedly protect the user from hazards of cellular phones. You can search the Internet to find the latest, ranging from antenna shields to whole-body shielding materials. Most experts believe that these devices take advantage of customers' misunderstanding and unfounded fears to sell products with no real value. First of all, cell phones that operate within the guidelines established by national and international safety panels have never been shown to pose a health risk to the user (see answers to other questions on cell phone safety on this website). Secondly, placing any kind of shield over the antenna of a cell phone will in most cases cause it to increase its RF output as it attempts to compensate for signal loss in the shield and maintain a quality phone call. The U.S. Food and Drug Administration published an advisory on cell phones several years ago that said if you are concerned about risks of using a cell phone, then simply use it less. That is still good advice today. Gary Zeman, ScD, CHP Lawrence Berkeley National Laboratory

    Click the link to add information to this solution:
    ARE THERE PRODUCTS AVAILABLE TO THE GENERAL PUBLIC THAT CAN BE PURCHASED PROTECT CELLULAR OR PORTABLE TELEPHONE USERS FROM RADIATION? IF SO, WHERE THESE FOUND?

  • What would be your recommendation for "power supply 2 (24vdc)" connecting to USB motion card? Are there any videos explaining it's connection to the relay coil? (not quite sure what relay coil is)

    A 24V connection to the USB motion card is only needed if you are using limit switches (inputs), powering the spindle/VFD speed and direction, and for the outputs, for powering other devices (mist, coolant, etc.).

    If you are using a VFD (Variable Frequency Drive, also called Inverter) for a spindle, they typically have a 24V out terminal that can be used with our USB motion card. If you are not using a spindle/VFD (we highly recommend one), then you will need to purchase a 24v power supply to power that side of the board.

    The outputs mentioned above are to connect to external devices and will require a relay (a mechanical switch that is controlled by a digital signal). This mechanical switch can turn on a device like coolant and mist, or even a router, if you are using one. A relay is required to turn on these devices because the devices are typically higher voltage, like mains (110v or 220v). So, a relay can turn on or off a high voltage device with a lower voltage (24v) signal.

    Click the link to add information to this solution:
    What would be your recommendation for "power supply 2 (24vdc)" connecting to USB motion card? Are there any videos explaining it's connection to the relay coil? (not quite sure what relay coil is)

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