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?

Question #: 273

Question: 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?

Current Solution

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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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?
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
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
[311] I am looking to use this type of thing with a pipe for theater. Where the pipe can be lowered and it would have electrical and signal cable inside. Is this good for that or should I look at something else?
This would totally work for that application. This cable carrier is used for any object that needs to move and carries some electrical or tubing within it. This cable carrier is great for cable management where you want to make sure the wires and tubes are in a position that you set, not where the wires and tubing want to go.
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[311] I am looking to use this type of thing with a pipe for theater. Where the pipe can be lowered and it would have electrical and signal cable inside. Is this good for that or should I look at something else?
Hello. I have bought an RnR Motion Controller and a YL260-A and I have it set up to the AVI from RnR to the VI1 of YL620-A but I'm getting that the RPM varies not like interference but like a drop from max value to min value. What could be happening?
Is the cable between the mach3 USB and the YL260 shielded. If that does not solve the problem, add an induction coil to the cable to reduce any current fluctuations.
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Hello. I have bought an RnR Motion Controller and a YL260-A and I have it set up to the AVI from RnR to the VI1 of YL620-A but I'm getting that the RPM varies not like interference but like a drop from max value to min value. What could be happening?
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.
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.
[788] Thanks for the oportunity to ask, I am building a cnc and using npn closed sensors could you help me with the conection of these, do i still connect them in series if i use more than two in each axis. Also you mention that a stop switch should be connected grd and input to the controller would that be done after the 24v power supply. Thanks r
If the sensors are NC (normally closed) you can wire them in series. If the sensors are NO (Normally Open) you can still wire them to the same input, but the wiring needs to be in parallel (like a ladder). I have more information on the following video:
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[788] Thanks for the oportunity to ask, I am building a cnc and using npn closed sensors could you help me with the conection of these, do i still connect them in series if i use more than two in each axis. Also you mention that a stop switch should be connected grd and input to the controller would that be done after the 24v power supply. Thanks r
Hello. I'm currently building my first CNC router, and I'm powering it with a 3 axis electronics kit that was purchased through your site. I chose to get the Mach 3 USB Breakout board, but now I'm wanting to try to use Linux CNC to work with the computer I have available. Will that work with this board?
The Mach3 USB will not work with Linux CNC. You can use our parallel breakout baord instead (if you have a computer that has a parallel port available).

Here is the link to that interface:
https://www.buildyourcnc.com/item/electronicsAndMotors-parallel-breakout-relay
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Hello. I'm currently building my first CNC router, and I'm powering it with a 3 axis electronics kit that was purchased through your site. I chose to get the Mach 3 USB Breakout board, but now I'm wanting to try to use Linux CNC to work with the computer I have available. Will that work with this board?
Building the 5x10 GreenBull, I went to install the ribs on the mid section of the gantry and you say in the video to skip a spot for the motor to sit, but I have 3 sections that are going to blank not just one like you show in the video. Do I skip more than one, am I missing ribs?
We apologize for the confusion! The current greenBull kit in the video is a 4' x 8' gB CNC machine, so we currently have a shorter Y-axis length, compared to the 5X/6X kits. However with the gB 5X you should skip every other section(or something similar so it is symmetrical), since we added the option for you to increase the number of ribs if you wish, but is not necessary for the CNC machine.
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Building the 5x10 GreenBull, I went to install the ribs on the mid section of the gantry and you say in the video to skip a spot for the motor to sit, but I have 3 sections that are going to blank not just one like you show in the video. Do I skip more than one, am I missing ribs?
[59] is it ok to use one pin for all of the limit switches wired NC and another pin for a z probe that is NO, or do all input pins need to be the same (NC or NO)? I would like to use LinuxCNC but will use Mach3 if necessary. a thanks!
It's generally acceptable to use one pin for all of your limit switches wired Normally Closed (NC), and another separate pin for a Z probe that is Normally Open (NO). LinuxCNC is quite flexible and allows for mixed configurations of NC and NO switches.

Just ensure you configure LinuxCNC correctly to recognize each pin's logic (Active low or active high). And perhaps run a few tests before running the machine.

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It's generally acceptable to use one pin for all of your limit switches wired Normally Closed (NC), and another separate pin for a Z probe that is Normally Open (NO). LinuxCNC is quite flexible and allows for mixed configurations of NC and NO switches.

Just ensure you configure LinuxCNC correctly to recognize each pin's logic (Active low or active high). And perhaps run a few tests before running the machine.
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[59] is it ok to use one pin for all of the limit switches wired NC and another pin for a z probe that is NO, or do all input pins need to be the same (NC or NO)? I would like to use LinuxCNC but will use Mach3 if necessary. a thanks!
I am building a blacktooth. I don't see in the instructions what screws are meant to fasten the power supply to the wood. The instructions show how to wire it but I don't see where it says which screws to use. I don't want to guess and end up being short later. Thanks. .
The blackTooth laser power supply will use 4 - #8 x 1" screws, and 4 - #8 nuts. As stated on step 10 here (https://buildyourcnc.com/blackToothLaserCutterAndEngraver.aspx#prettyPhoto/10/)
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I am building a blacktooth. I don't see in the instructions what screws are meant to fasten the power supply to the wood. The instructions show how to wire it but I don't see where it says which screws to use. I don't want to guess and end up being short later. Thanks. .
From your assembly instructions, it appears your table top is 3/4 thick. I planned to use a thicker table at 1 1/2 thick. I realize I will need longer bolts to attach the x-axis guide rails, but will the y-z gantry adjust for a table that thick? I am building a BlackFoot.
I apologize but the gantry legs will only be able to accommodate 3/4" thick table top (gantry sides to be specific(https://buildyourcnc.com/blackFoot48v40.aspx#prettyPhoto/28/)).This is due to the available adjust ability on the gantry legs between the v-groove bearings that ride on the top X-axis rails, and the ones that tighten on the lower rails.

The Y-axis (width of the table) will have no problem with the table top being thicker, but the X-axis rail screws and gantry legs will not accommodate the 1"- 1/2" table top.
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From your assembly instructions, it appears your table top is 3/4 thick. I planned to use a thicker table at 1 1/2 thick. I realize I will need longer bolts to attach the x-axis guide rails, but will the y-z gantry adjust for a table that thick? I am building a BlackFoot.
I am interested in using the Mach3 USB interface board. I was wondering if there was a way to run a torch height controller with this board for use with a plasma cutter, and if so do you know of any THCs that will work. Thank you.
Yes, you can connect a THC, Torch Height Controller, with the Mach3 USB controller. The THC uses the inputs to determine if the z axis needs to move up or down according to the arc of the plasma torch. The THC connects its outputs to the inputs of the controller so the controller will be informed of the states of the plasma torch.
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I am interested in using the Mach3 USB interface board. I was wondering if there was a way to run a torch height controller with this board for use with a plasma cutter, and if so do you know of any THCs that will work. Thank you.
THERE HAS BEEN A CELL PHONE BASE INSTALLED IN THE FIRE TOWER. PANELS ARE VERTICAL AND LOCATED ABOUT 75 FEET AT TOP OF UNLIKE SOME TOWERS I HAVE SEEN NO ROUND DISKS BEAMING LIGHTS. NIGHT, TOWER MATERIAL DARK. DOES THIS MAKE ANY DIFFERENCE RELATED HEALTH ISSUES WITH RF EXPOSURE IT POSSIBLE RECEIVE-ONLY TRANSMITTER ?
There has been a cell phone base installed in the fire tower. The panels are vertical and located about 75 feet at the top of the tower. Unlike some towers I have seen there are no round disks and no beaming lights. At night, the tower and cell phone material are dark. Does this make any difference in any related health issues with RF exposure and is it possible the tower is a receive-only transmitter ?
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THERE HAS BEEN A CELL PHONE BASE INSTALLED IN THE FIRE TOWER. PANELS ARE VERTICAL AND LOCATED ABOUT 75 FEET AT TOP OF UNLIKE SOME TOWERS I HAVE SEEN NO ROUND DISKS BEAMING LIGHTS. NIGHT, TOWER MATERIAL DARK. DOES THIS MAKE ANY DIFFERENCE RELATED HEALTH ISSUES WITH RF EXPOSURE IT POSSIBLE RECEIVE-ONLY TRANSMITTER ?
Does the break out board come with the short ribbon connectors? Mine was soldered together and the new one comes with a plug. If it does not come with one where do I get one, I need the short ribbon connector to go with it.
The Breakout Board is a single product assembly, it will not include a short ribbon cable nor connectors. You can find the parts required to build or make your specific ribbon cable in our motion electronics page or follow the links below:

25 Conductor Flat Ribbon Cable: https://buildyourcnc.com/item/electronicsandmotors-connector-DB25-conductor-ribbon-cable

25 pin D-Sub Male connector: https://buildyourcnc.com/item/electronicsandmotors-connector-male-dsub-DB25-ribbon

25 pin D-Sub Female connector: https://buildyourcnc.com/item/electronicsandmotors-connector-female-dsub-DB25-ribbon

You can also buy a complete DB-25 cable:
Male to Female Parallel Cable: https://buildyourcnc.com/item/electronicsAndMotors-cable-wire-db25-male-female
Male to Male Parallel Cable: https://buildyourcnc.com/item/electronicsAndMotors-cable-wire-db25-male-male
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Does the break out board come with the short ribbon connectors? Mine was soldered together and the new one comes with a plug. If it does not come with one where do I get one, I need the short ribbon connector to go with it.
My Z-axis seems to be reversed on a fully assembled machine... I've tried reversing it in the config settings on Mach 3, but to no avail. What do I need to do? IS this a wiring issue that was not done correctly at the factory?
If your Z axis is moving in the opposite direction, go into Mach3, click on config, ports & pins, then click on the motor outputs tab. You will see the axes labeled on the left and the parameters labeled on the top of this dialog box. Toggle the dir low active for the z-axis.

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What if I'm having the same issue on a different axis?

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You can follow the same procedure as with the z-axis. When you get to the motors outputs tab, toggle the dir low active checkbox for the axis that you would like to change.

If you are using another control program, let me know and I will add the recommended action here.

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Girbl

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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I have a grbl laser machine tronhoo machine that is running back wards and side ways wrong help

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My Z-axis seems to be reversed on a fully assembled machine... I've tried reversing it in the config settings on Mach 3, but to no avail. What do I need to do? IS this a wiring issue that was not done correctly at the factory?
BUILDING ONE OF YOUR GREENBULL 6X LONG AND 2.2 KILOWATT SPINDLE DOES NOT FIT. SEEMS LEAD SCREW YOU SENT WITH KIT IS SHORT 42" LOOKS LIKE IT NEEDS TO BE 5 OR 6 INCH LONGER. THIS CORRECT? WHAT THE NEEDED LENGTH FOR UNIT?
The leadscrew length for the greenBull long Z-axis is 47 inches.

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BUILDING ONE OF YOUR GREENBULL 6X LONG AND 2.2 KILOWATT SPINDLE DOES NOT FIT. SEEMS LEAD SCREW YOU SENT WITH KIT IS SHORT 42" LOOKS LIKE IT NEEDS TO BE 5 OR 6 INCH LONGER. THIS CORRECT? WHAT THE NEEDED LENGTH FOR UNIT?
WHILE RESEARCHING A NEW CORDLESS PHONE TECHNOLOGY (DECT [DIGITAL ENHANCED TELECOMMUNICATIONS] 6.0), I SAW REFERENCE TO POTENTIAL BRAIN DAMAGE AND/OR CANCER DUE THE RADIATION FREQUENCY AND PULSES FROM THESE DEVICES.
There has been a lot of public concern around the world about potential health effects from using mobile phones. This concern has spilled over to other cordless phone technologies and indeed to many other devices that transmit radiofrequency energy.
Scientists have been studying possible health and biological effects of radiofrequency energy since World War II and even before, and the literature at this point is very large. Since the 1990s many studies have been conducted on possible health effects of mobile phones. I am not aware of any studies that have searched for possible health effects of DECT phones specifically, but DECT phones operate in a generally similar frequency band and at similar average power levels as many mobile phones.

Health agencies around the world have repeatedly examined the scientific literature and have found no clear evidence of health effects from use of mobile phones, or indeed from any exposures to radiofrequency energy at levels below international exposure guidelines. But these agencies also point out the limitations to the data (for example, lack of data regarding long-term use of mobile phones) and they all call for more research. The most recent report on this subject is by a group affiliated with the Health Protection Agency of the United Kingdom (U.K.) (http://www.mthr.org.uk/documents/MTHR_report_2007.pdf).

Some activist groups (such as the one whose website you cited) claim that there are health hazards from mobile phones and other sources of radiofrequency energy at levels below international exposure limits. Such claims are not reflected in opinions of health agencies including the U.K. Health Protection Agency, the World Health Organization, and other major health agencies.

That said, if a person is concerned about possible health effects of a cordless or mobile phone, he or she might consider using a hands-free kit (which reduces exposure to the head) or simply not use such a phone at all.

Kenneth R. Foster, Professor
Department of Bioengineering
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WHILE RESEARCHING A NEW CORDLESS PHONE TECHNOLOGY (DECT [DIGITAL ENHANCED TELECOMMUNICATIONS] 6.0), I SAW REFERENCE TO POTENTIAL BRAIN DAMAGE AND/OR CANCER DUE THE RADIATION FREQUENCY AND PULSES FROM THESE DEVICES.
Hi, I received a laser tube last week, and it was brokken in the packet. I tried to write to customer service but no answer so far. How do you handle this? The packet was not dammaged in any way. I was only able to see it was broken when it was complete unpacked.
When we receive an email pertaining to shipped product issues, they are forwarded to our shipping department. If you do not receive a response, for any reason, please contact us again by email, and/or give us a call at 281-815-7701

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Hi, I received a laser tube last week, and it was brokken in the packet. I tried to write to customer service but no answer so far. How do you handle this? The packet was not dammaged in any way. I was only able to see it was broken when it was complete unpacked.
How to determine lead screw length needed. My Thomson 1 1:4 rails are 60 inches long roughly for the router I’m building. I know I have to have it long enough to couple up with the stepper motor of course but does it matter if it’s a little long on the other end
It generally does not matter if it is longer at the other end as long as the lead screw provides the desired travel for that axis. The lead screw will only need to be long enough for the travel, plus any structure and lead-nut positioning.

For example:
- The motor that will turn the lead screw will need to be mounted at some position (generally at one end of the axis). In many cases, this positioning will be mounted where some of the lead screw will not be used (the lead nut will not be able to moved close to the coupling of the lead screw to the motor shaft). Add some of the length of the lead screw to be inserted into the coupling.

- If the lead screw will contain bearings at either end of the travel, that portion of the mechanical assembly will need to be considered in the lead screw length.

- The lead-nut will need to be mounted in a position on a structural member of the part that is to move. The distance from the part of the structure that will extend closest to the motor will have some distance to the position of the lead nut. This distance will need to be added to the lead screw length.

Add these discrepancies to the length of the lead screw and the travel length and you will have the final length.
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How to determine lead screw length needed. My Thomson 1 1:4 rails are 60 inches long roughly for the router I’m building. I know I have to have it long enough to couple up with the stepper motor of course but does it matter if it’s a little long on the other end