Cellular telephone base stations are low-powered radiofrequency (RF) transmitters which operate at around 850-900 or 1800-1900 MHz (depending on the technology and region of the world). RF energy in a similar frequency range is used by many other technologies such as microwave ovens, UHF television, other communications systems, and radar. Health and safety issues related to RF energy have been studied for many years and there is an immense literature on the subject. Here are some sources that review health and safety issues related to RF energy from cellular base stations.

A fact sheet published by the World Health Organization. There is also a Spanish version available on the WHO EMF website.
Also see the IEEE EMBS Committee on Man and Radiation Report. Other reports are available through its website.
The International Commission on Nonionizing Radiation Protection (ICNIRP) has published a lot on health and safety of RF energy. See its website. The ICNIRP published an article that describes the ICNIRP exposure limits for RF energy and their scientific rationale. See "Guidelines for Limiting Exposure to Time-Varying Electric, Magnetic, and Electromagnetic Fields (up to 300 GHz)," Health Physics Vol. 74, No 4, pp 494-522, 1998.
A very detailed assessment of the scientific evidence related to health and safety of mobile telephones and base stations is in the recent (May 2000) report by the Independent Expert Group on Mobile Phones (IEGMP) titled "Mobile Phones and Health" This study concludes "the balance of evidence to date suggests that exposures to RF radiation at levels below [international exposure guidelines] do not cause adverse health effects to the general population" but that "there may be biological effects at exposures below those guidelines." Public exposure to RF energy from cellular base stations is invariably far below the ICNIRP exposure guidelines.

Kenneth R. Foster
Professor, Bioengineering
University of Pennsylvania

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I'M SEARCHING FOR INFORMATION ABOUT THE HEALTH RISKS OF CELLULAR ANTENNAS' RADIATION. I NEED SCIENTIFIC (SCIENTIFIC PAPERS IN JOURNALS) THIS.

The connections between the driver and the breakout board(USB/Parallel)22-24 AWG wire is preference also going from the potentiometer going to LSPS(laser power supply) , now going from the power supply to the drivers/laser power supply 16-18 AWG wire is our preference.

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I'm about to order your laser cutter , item 279 and a little confused.. in your faq it states you need wire and connectors for assembly, can you be specific on amount and guage of wire or tell me where to find that information?

See the question on our "Ask the Expert" question-and-answer list on cellular towers under nonionizing radiation for a discussion of RF safety issues associated with cellular radios. The technology underlying cellular radios and base station antennas is similar around the world, but there are differences in systems design and RF safety limits in different countries. For a summary of cellular radio RF safety issues with attention to international differences see the excellent Web page, Cellular Phone Antennas (Base Stations) and Human Health, by John E. Molder, Ph.D., from the Medical College of Wisconsin. Gary H. Zeman Sc.D., CHP

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I LIVE IN ITALY AND WISH TO KNOW MORE ABOUT RADIATIONS CAUSED FROM MOBILE TELEPHONES. TELECOM WOULD LIKE PLACE A WIRE-ANTENNA THE HEARTH OF MY TOWN, I'M AFRAID IT. WHICH KIND RISK HEALTH COULD IT CAUSE? THANK YOU IF WILL SEND ME SOME INFORMATION SCIENTIFIC ARTICLES THIS PROBLEM!

Yes, if you need a replacement part on your machine please call us at 281-815-7701.

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I have a blacktooth laser engraver. The Y Axis stepper motor needs to be replaced. Can you please provide me with the information I would need to replace this motor.

The wire that is connected to the spindle can be a simple extension cord, that you find at a local hardware store. However there is a missing wire that is required(ground) which will have to be the same amperage of the extension cord.

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What wire do I need to power the spindle (ie, from the 220 outlet to the spindle). Would a dryer cable work? Is there specific amperage the wire needs?

We carry several sizes of lead screw and stepper motors on our website, for example here https://buildyourcnc.com/Item/mechanical-leadscrews-lead-screw-!5-5-starts-10-tpi and here https://buildyourcnc.com/ProductSearchResults.aspx. Please call us at 281-815-7701 to discuss the particular lengths you would need and shipping options.

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I have a project very similar to cnc machine. I need 3 lead screws of 1.8 m with all set (supports, bearings...etc). and 3 NEMA 42 motors that I can connect with. if those are available, I need the information about shipping to Oman or UAE.

There are two things to consider when using two stepping motors on a single axis. Since you want both motors to spin at the same rate and possibly in the same direction, you need to connect both motor drivers to the same breakout board pins. For example, if you want two motors on the x-axis and the x-axis pins on the breakout board are #2 for step and #3 for direction, the #2 will connect to the step (cp) terminal on each driver and the #3 will connect to the dir (cw) terminal on each driver.

However, if the motors will be opposing (one motor will need to spin in the other direction), you will need to consider either flipping the rack on one side, or adding a circuit to invert the direction (#3) signal going to that driver.

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I'm planning a rack and pinion style gantry, and need clarification on how to slave a second stepper to the Y (or X). Can you direct me to that information for your products?

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 accept many forms of payment, but online, we accept major credit cards (Discover, Visa, MasterCard and American Express) in addition to checking out with Paypal. Depending on what is ordered, a machine vs. a la cart parts, will arrive at your destination according to the shipping method chosen. A machine may take an extra week to be delivered.

Once paid, there are no changes in the amount for the purchase.

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good day I have my list of products in the cart, and before making the purchase need to ask 1. I need to know if I can pay by bank card HSBC Visa 2. If I pay today, As approximate time come to Mexico City? 3. Ordered the shipping information online, and I chose standard UPS. There may be changes in the amount? 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?

VFD settings........
1) To program the VFD, wire it up, plug it in. It takes several seconds to come to life.

2) Push the PRGM button to enter programing mode.

3 )Push the SET button. The display will read PD000.

4) If you push the SET button again, it will display the present setting of PD000.

5 )By pushing the up or down arrows, you can change the setting to whatever it needs to be. (This is just an example. PD000 needs no changes)

6)Push the SET button again to lock in the setting of PD000 and advance to the next number, in this case, PD001.

7) Push the SET button and it will display the present setting of PD001. Again, use the up and down arrows as necessary to set PD001, then push SET again to lock it in.

Note: You can also scroll through the PD numbers with the up and down arrows.

8) make all settings this way.

9) by pushing the SET button you can scroll through the settings. First push of SET moves to the next number, second push displays it's setting, third push moves to the next PD number.

Note- If you take too long, it will leave the programing mode on it's own. If it does, just push PRGM again to return to programing mode. Then press SET and continue what you were doing.

10) Start with PD013. Set it to 1, which returns the settings to the factory settings.

11) Then set PD005 to 400, PD004 to 400, and PD003 to 400 IN THAT ORDER.

12) Then set the following: PD041=8, PD144=3000

13) Set PD209=50

That's it for the programing. You should get 24000RPM when you push RUN.

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I just received a replacement spindle (2.2kW 220v). However, when I attempted it use the new spindle, it would only reach 1500 rpm. Is there something I need to change on the spindle controller?

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?

I will find this answer when I get into the office on Monday, but I have no problem sending out a replacement DVD out to you. If you would like to do this, please call us on Monday and let us know that you need a replacement DVD

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Hi Patrick back in 2013 I purchased the cnc hardware and plans kit. I misplaced the dvd which shows you how to configure the mach 3 software to the cnc machine I build. I it possible to get another dvd. Or do you have the information somewhere you the website or youtube?

VFD settings........
1) To program the VFD, wire it up, plug it in. It takes several seconds to come to life.

2) Push the PRGM button to enter programing mode.

3 )Push the SET button. The display will read PD000.

4) If you push the SET button again, it will display the present setting of PD000.

5 )By pushing the up or down arrows, you can change the setting to whatever it needs to be. (This is just an example. PD000 needs no changes)

6)Push the SET button again to lock in the setting of PD000 and advance to the next number, in this case, PD001.

7) Push the SET button and it will display the present setting of PD001. Again, use the up and down arrows as necessary to set PD001, then push SET again to lock it in.

Note: You can also scroll through the PD numbers with the up and down arrows.

8) make all settings this way.

9) by pushing the SET button you can scroll through the settings. First push of SET moves to the next number, second push displays it's setting, third push moves to the next PD number.

Note- If you take too long, it will leave the programing mode on it's own. If it does, just push PRGM again to return to programing mode. Then press SET and continue what you were doing.

10) Start with PD013. Set it to 1, which returns the settings to the factory settings.

11) Then set PD005 to 400, PD004 to 400, and PD003 to 400 IN THAT ORDER.

12) Then set the following: PD041=8, PD144=3000

13) Set PD209=50

That's it for the programing. You should get 24000RPM when you push RUN.

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I JUST RECEIVED A REPLACEMENT SPINDLE (2.2KW 220V). HOWEVER, WHEN ATTEMPTED IT USE THE NEW SPINDLE, WOULD ONLY REACH 1500 RPM. IS THERE SOMETHING NEED TO CHANGE ON CONTROLLER?

All of our machines exhibis radial loads on all of our bearings with the exception of the bearings on the z-axis lead screw that holds the lead screw in place. These lead screw bearings are held between a coupling and a collar and the load on these bearings are well within their specifications.

The v-groove bearings that are used for movement along rails have load centered between the double races of the bearings (from where the point load from the rails exist within the center of the "W" profile of the bearing). There may be slight axial load on bearings on the z-axis positioned on the rails for z-axis up and down movement and y-axis side to side movement where torsion load exists from load on the end mill during the milling process; however, this is a very small fraction of total load on these bearings are are well within specification.

Can you let us know where you see side (axial) load on our bearings, so we can better describe the conditions? Thanks.

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I've been interested in your machines, but the designs seem to side load most of the v-bearings, which raise questions about bearing life, and reliability. Isn't there a better choice of bearing configurations?

Sure, connect O2 (output #2) on your mach3 USB board to the GND side of your relay coil. Connect the 24V power supply to the positive side of your 24v relay.

You will want to connect a flyback diode (1N4007) between the coil connections to make sure the coil back current does not damage the Mach3 USB board.

Refer to this diagram:
https://www.buildyourcnc.com/Documents/Electric%20Wiring%20Diagram.pdf

Please let me know if this helps and if you need further guidance.

Thanks

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I recently purchesed a USB Mach3 breakout board and need help setting mach3 to use a relay to start the router can you show how to set the pins and which port to use on the board to attached the relay?

If you are referring to aligning the rails so that the rails are perfectly parallel:

It is important to make sure one rail (a rail at one side of the table) is perfectly aligned first. Do this by fastening one end of the rail to the table (flush with the table edge), then fasten the other end (flush with the table edge). The rail may not be perfectly straight at this point, but that's ok. This process includes the top and bottom rail, fastening and positioning simultaneously.

You are going to fasten the midpoint of the rail. Get a clamp ready so that you can freeze the rail in place. Look down the rail from one end. This is a good way to determine if the rail has a curve, or is straight. If there is a curve, move the rail midpoint laterally until the rail is straight while looking down the rail from one end of the rail. This may take a couple of people to do, one looks down the rail, the other moves it slightly until it is straight and then clamps the rail. Drill and fasten the midpoint when satisfied. Repeat this process, fastening at the midpoint between screws.

Now place the gantry on the table with the v-groove bearings resting on the one rail side. Add the next rail to the other side of the table. Position the rail so that it is directly under the other bearings. Make sure the gantry is at the extreme end and fasten the rail at that end. Move the gantry along the and fasten the rail as you move the gantry so the rail auto-positions itself.

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Thanks for your answer. So the next step is making certain that the gantry is exactly perpendicular to the x axis. Do you just place a square on the rail and adjust one or both chains as needed?

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Is there a specific process for aligning the x axis on the greenbull? There is mention of it at the end either the rail or gantry installation but I could not find it anywhere.

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?

If the Z-Axis is moving down when you press the page up or page down (or by moving the z-axis by another means like with an MPG, Pendant, or the built-in MPG in Mach3), then the direction signal wire is not connected correctly. The direction signal wire works by moving in one direction with a low signal (like gnd) and moving in the other direction with a high signal (like 5v). If the signal stays at one of the two signals, it will only move in the direction of the current signal state. Recommended action is to determine if the DIR- and DIR+ signal wires are connected securely and make good contact at the driver and controller sides.

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I installed a pokeys57cnc and use Mach3 for the mill. When I page up or down the Z axis moves down. Is there a setting I need to change? I checked the Z axis wiring and it matches the X and Y axis which function correctly.