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?

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?

Headsets have been tested by the manufacturers and meet the current ANSI/IEEE standards for RF safety, the same standards that the Federal Communications Commission enforces under the Telecommunications Act of 1996. These standards place limits on the specific absorption rate (SAR) of radiofrequency (RF) energy in the body. Recent inflamatory articles in British press were not substantiated by testing in ISO-accredited testing facilities at Motorola. Manufacturers of cellular 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 may be available from the FDA or from the FCC. Ron Petersen, Lucent C.K. Chou, Motorola

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HAVE THERE BEEN ANY STUDIES OF POSSIBLE RADIATION DANGER FROM HEADSETS USED WITH HANDSETS CORDED TELEPHONES? I A TELEPHONE BATTERY-POWERED HANDSET. THIS HANDSET HAS JACK FOR HEADSET, SO YOU CAN WALK AROUND THE HOUSE AND YARD ON YOUR BELT WHILE TALK INTO HEADSET. EITHER OR HEADSET GIVING OFF RADIATION, LIKE CELLULAR PHONE? DANGEROUS AMOUNT RADIATION?

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?

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

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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?

Yes, we can ship to the UK. We ship there often. The shipping time will be based on the selection you make in the shopping cart when you press the calculate shipping button. We work with many universities and we can process the order according to your administration's needs.

Here is our canned response for general shipping questions:
You can determine if the country is serviceable by:
- selecting the items you want to purchase on the website
- go to the cart (shopping cart top left of any webpage)
- log in, or register
- Enter the address and click on calculate shipping.

The webpage will return the direct rates and whether your area is serviced or not. Feel free to enter any address as long as you are able to receive the package from that address.

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I am running a research project at Bath University in the UK based on desktop CNC machines and their potential use in the department of engineering. Will you guys ship to the UK & what is the estimated time? Thank you.

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?

You may want to try using a ferrite core or an inductor in addition to the shielded cable. Also, make sure you are grounding the shield at both ends. Even though this is not high frequency, grounding the shield at both ends in a motor scenario may help. Also, try to reduce any parallel wire runs.

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[575] Hi, I plug HY 220v spindle on the board. It work, but the is a unstable frequency on the spindle. I put shielded wires from BOB to Inverter, and from Inverter to Spindle. But the problem still there. I read that I have to put a Analogue PWM, is that true, or I have problem with my wires... Thank you

Here's a link to the blackTooth laser that we sell, https://www.buildyourcnc.com/blackToothLaserCutterAndEngraver.aspx. It will vary depending which materials you are using, but keep in mind on how deep you are cutting since the blackTooth only cuts 1/4" inch(dept) at a time.

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We will be carrying a 8' x 4' laser cutter in the near future. We will also design an attachment for the GreenBull to contain a laser tube at the head of the machine to convert a greenBull into a laser cutter.

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Im in the market for a laser cutter with the ability to cut 8'x4' boards (different materials) and up to 5" height. I bought a greenbull 10'x5' a while back from you guys

Dealing with your CNC upgrade we will need a good detail on exactly what you plan on keeping and reusing, all technical information about the parts that you keep will make our recommendations more precise for your application.

Please email customerservice@buildyourcnc.com for any quote related questions.

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I am upgrading a CNC with 3 stepping motors, and its all I want to keep. What technical information do you need in order to receive a quotation from you with the new items I need to buy from you?

We have the image at that size to encourage the purchase of the kit from us. This helps to keep buildyourcnc alive and allows us to fund development of other awesome low cost machines.

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could you make available a larger size picture of the exploded view of the BlackTooth laser cutter? I would like to use for reference when building my laser cutter, but it is too small to be really useful.

What organization are you with and how will you use the CNC?

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I would like to do a review on your 4x8 table, we are the new kids in town looking to give honest reviews no BS. We want no affiliate bonus or sponsorship we only ask for free product so that we can educate ourselfs and others while giving honest feedback

The dimensions for the #40 drive sprockets will be 1.835" radius tooth to tooth , .575" from teeth to teeth, 0.600" / 3/5 ID, 1.249" OD.
Now the idler sprocket dimensions (same format):
Radius ttt: 2.963"
Fttt: 0.535"
ID: 0.600" / 3/5
OD: 0.825"

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I am designing/building a cnc plasma cutter and I would like some info on some of your parts. Would it be possible to get dimension and/or drawings (or models) of the #40 drive and idle sprockets?

Yes, the Mach3 USB board has two terminals that require 24V connection. Most VFDs have a 24V output that can be used to power this part of the Mach3 USB board.

The V+ and V- on the Mach3 USB is not absolutely necessary to operate the CNC machine/router. The V+ and V- of the Mach3 USB board powers the outputs, inputs, and spindle's speed and control.

Here is the Mach3 USB link for more information:
https://www.buildyourcnc.com/item/electronicsAndMotors-electronic-component-breakout-Mach3-USB-Board

The new YL600 VFD we have in stock may not have this 24V output. There is a 12V terminal, but I have not tested that terminal if it outputs 12V, or if it is a 12V input. If you are only conecting limit switches to the Mach3 USB and need to power that portion, 12V will be sufficient.

I will delve into these aspects in far more detail on video.

Thanks and Merry Christmas to you as well!

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Hey Guys, I have a brand new redleaf and 5x. In the final stages of wiring and wondering a few things. Can I connect the Mach3 USB board V+ V- to my frequency inverter (type YL600-2s-2k20)? If so where? Will your upcoming (part 2)video deal with this as well as final connections for limit switches and stop button? Merry Christmas!

If you purchase the greenLean, you will get everything you need except a router, computer to operate the machine, and software to control the machine. You state that you have a computer. You can use this computer, but you will need to determine if it has a parallel port, or if you are going to need the USB controller option. As for the software, there are too many different options for you to choose from. We would not be able to tell you which to get, and how much it will cost you. This is a matter of preference. I can tell you, however, that you will need 3 types of software to complete a CNC project. You will need CAD software to design your design, CAM software to add tool paths and convert the design to g-code, and then control software to take the g-code and operate the machine.

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I am building a wet plasma table for my shop that is 8'x 16'. I will need hardware and software. Please heko me wuth the list, My phone is 9124273734. I would like to talk with someone if possible. Thanks, Rus

Generally, 3D printers require the following components:

Electronics to move the motors, limit the motion and extrude the filament:
- Stepping motors, one for each axis (X, Y and Z), and one for each extruder

- Stepping motor drivers that are capable of allowing a current draw that matches the stepping motor connected to the driver. https://www.buildyourcnc.com/item/3D-Printer-Component-electronicsAndMotors-stepper-driver-2!5a-FDMElectronics-driver2!5a

- Arduino Mega 2560 to serve as the g-code interpreter. https://www.buildyourcnc.com/item/3D-Printer-Component-electronicsAndMotors-electronic-component-arduino-mega-2560-FDMElectronics

- Arduino shield that breaks out all of the connections from the arduino (3D printer main board). https://www.buildyourcnc.com/item/3D-Printer-Component-electronicsAndMotors-3d-printer-mainboard-FDMElectronics-3dprintermainboard

- Extruder to control the temperature of the hot end (receive temperature readings using a type K thermocouple and send current to the heating cartridge, or power resistor). https://www.buildyourcnc.com/item/3D-Printer-Component-electronicsAndMotors-extruder-controller-FDMElectronics

- End stops to limit the travel of each axis. https://www.buildyourcnc.com/item/3D-Printer-Component-electronicsAndMotors-electronic-component-end-stop-switch-safety-FDMElectronics-endstop

- Type K Thermocople to sense the heat at the hot end. https://www.buildyourcnc.com/item/3D-Printer-Component-typek-thermocouple-heat-sensor-newbiehack-sensors-typek-thermocouple-heat-sensor

- Extruder with motor and hot end. https://www.buildyourcnc.com/item/3D-Printer-Component-extruder

The software to run a 3D printer for our electronics is replicatorG.

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I am building a big 3d printer using 3 nema 23 and two nema11 for dual head extruder. I need a list of the rest of the stuff I would need including hardware to run these motors and the sofware I would need.

Dealing with our linear guide rails and blocks we will need to know more info specifically with your machine, and also to check our current stock for interchangeable parts with your machine.
Please email us at customerservice@buildyourcnc.com, for further assistance.

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good day I'm interested to know how I can buy spare parts for Hyundai WIA around, looking for parts such as linear guides, you can assist me to sell me The reference hyunday wia is L 280 LM 2013

241Am is naturally radioactive. It decays by emitting alpha particles of about 5 MeV energy. It also emits some low energy beta particles and gamma rays in the keV range, which can also be detected by Monitor 4. The alpha particles interact with your aluminum foil and produce the isotope 30P and a neutron. 30P has a half life of about 2.5 minutes and decays to the stable isotope 30Si by positron emission. The positron will annihilate with an electron producing two 0.511 MeV gamma rays that are easily detectable. Note the decay of 30P to 30Si will not necessarily be to the ground state of the nucleus, but to one of the several excited states of 30Si, which will quickly decay by gamma emission. The more probable of these gamma rays have energies between 1.2 MeV to 2.2 MEV. These are also detectable with your detector. Last but not least, is the neutron which was emitted from the interaction alphas with the aluminum. Addition of paraffin disk, since it contains lots of hydrogen atoms, will slow down the neutrons. Slow neutrons can be captured by nuclei in paraffin, mica window and the body of the detector itself. The results are several other isotopes that can decay by emitting gamma and other radiation.

This is how you have increased the radiation from your 241Am source.

Kamran Vaziri

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I HAVE A MONITOR 4 RADIATION SURVEY METER WITH .36" DIAMETER MICA END WINDOW GM TUBE. PLACED 241AM SMOKE DETECTOR BUTTON IN WRAP OF ALUMINUM FOIL, THEN 1/8" PARAFFIN DISK ATOP THE WRAPPED BUTTON. ARE 4X ABOVE BACKGROUND READINGS FROM PROTON EMISSION OR SOME OTHER PARTICLE RADIATION?

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?