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Thread: No Radio Reception with cnc on...

  1. #1
    Join Date
    Nov 2016
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    New Mexico
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    Default No Radio Reception with cnc on...

    Our Desktop D2417 Shopbot interferes with radio reception. With the machine ON, our radio reception is bad. We move the radio away, even 25 feet, and still have trouble.

    What is causing this? Should we be concerned about our cnc machine?
    Shielding?
    Our most important shop tool is the pencil sharpener!

  2. #2
    Join Date
    Dec 2005
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    Pro Signs, Coal CIty IL
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    Default

    Not sure, but I imagine someone has run across this before.
    I learned several years ago that the TIG welder would stall the CNC. I would start the CNC, then go in the next room and work on welding projects. They aren't on the same circuit, not even the same breaker box. It took a couple times to realize I was the one causing the stall. It never hurt anything, but I stopped welding whenever the CNC was on.

  3. #3
    Join Date
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    Hobby-Tronics, Chiloquin Oregon
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    "Electromagnetic Interference "
    "Like all devices that use electrical signals, USB is susceptible to Electro-Magnetic Interference (EMI). EMI may cause signal degradation that will appear as static on USB audio devices or unreliable operation of other devices."

    The communication between your control pc and the Bot box is via USB. Make sure you don't penny pinch when buying USB cables for your BOT. Russ
    AKA: Da Train Guy

  4. #4
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    Nov 2016
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    Default

    Ok and thanks.
    Still using the usb cable that came with the machine.
    Will look for a better cable somewhere.
    Our most important shop tool is the pencil sharpener!

  5. #5
    Join Date
    Dec 2000
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    Thorp, WI
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    Default

    Do you have a spindle/VFD? You may need to have a filter installed. Check with SBHQ and see what they have to say. I had a problem when we first got DSL in our rural area. Every time I started the spindle, the DSL would get kicked offline. Got a filter for the spindle/VFD from SB and it's been fine since.
    Scott

    If guns kill people, I guess pencils misspell words, cars drive drunk and spoons make people fat.

    "Those who hammer their guns into plows, will plow for those who do not" - Thomas Jefferson




  6. #6
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    Not an advertisement but . . . I get my cables from BestBuy and I always ask the clerk which ones THEY recommend. I also use one of their USB hubs and so far I have not had any communication issues. As a somewhat related subject, my wife's laptop is a cheapo and the internal laptop USB ports are very poorly designed. USB cables will not stay in place and since they are part of the circuit board of the laptop are not repairable. I hope you find a workable solution. Nothing is worse than intermittent issues that interfere with fun Botting! Russ
    AKA: Da Train Guy

  7. #7
    Join Date
    Nov 2016
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    New Mexico
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    No spindle. Using a router.

    Talked with shopbot yesterday. Asked if they recommend a better USB cable (still using the original cable that came with the machine). Here's their reply...

    ... "The USB cable does not have to be anything special. We recommend a simple USB A to B cable that is 10' or less. You can find these anywhere."

    Hmmm...?
    Our most important shop tool is the pencil sharpener!

  8. #8
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    Well see they're in NC which has high humidity, so much better connections! In my area which is extremely low humidity during the summer months the issue is static discharge / grounding issues, especially with the dust collection stuff. Anyhow, I hope you find out what the demon is - sooooon! Russ
    AKA: Da Train Guy

  9. #9
    Join Date
    Oct 2009
    Location
    Elgin Illinois
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    Hello Shopbot friends:

    Having worked as an electronics engineer in new product development for many years, it must be understood that any electronics with switching circuitry, (anything from SCR based light dimmer switches, to PCs with high clocked CPU boards and switching power supplies, generate intense broad spectrum electromagnetic radiation that if unshielded, would wipe out radio communications within the confines of a house. That reality is what resulted in the FCC creating standards that if followed, will minimize the interference of the aforementioned devices with near range RF communications. Open any modern electronics, and you will see tightly sealed metal, well grounded enclosures, with small (in RF terms) openings, little bypass capacitors, ferrite beads, line filters, and other tools of the trade that manage when correctly applied, to suppress and contain RF emissions, and thusly not wreak havoc with your radio reception.

    If I take the side of my PC case off, I can't use my AM radio that sits near by. Put the cover on, and then the radio is fine.

    My point with having worked in this area, is that any such digital/noisy electronic product must get FCC approval by a certified laboratory. I have worked on products, that when they are tested, go into an RF anechoic chamber, with big arrays of antennas aimed at the device under test. In the broad spectrum sweeps which are conducted, if the limits of emitted RF emissions are exceeded at any frequency, everything stops, and electronic band-aids are applied, wires moved, capacitors added, ground planes reworked, grounding within the chassis gets altered, until the limits are no longer exceeded. I have made changes in the past, which I know, had one wire moved a little, we would have failed the test.

    So look inside of your Shopbot at all the wires, the fancy shielded, well grounded box, and realize that someone had to work like mad to get that unit to pass. And if someone made a prototype pass at an FCC test lab, who's to say that some small production change in the next batch of products, didn't just toss that careful little RF band-aid out the window.

    I wouldn't personally worry at all about where the RF is getting out,,,,,,,, it could be anywhere, and to exactly figure out where the RF was escaping (through the USB cable, or the power cable, or the motor driver wires etc), and further how to stop it, could cost thousands. It is what it is.

    In my house, the worst source of interference with my AM radio reception, comes from my old time SCR based light dimmers. I know at night if I put some lights on the low setting, I can forget about listening to AM radio. And I don't even think of having my radio on if I am going to turn on my Bot, I'm fine with that. (Or listen to an FM radio, the genius invention of Major Armstrong, that doesn't pick-up stray spurious electronic emissions and attempt to "demodulate" them along with your favorite radio program............ Chuck
    Chuck Keysor (circa 1956)
    PRT Alpha 60" x 144" (circa 2004)
    Columbo 5HP spindle
    Aspire 9.0, Rhino 5

  10. #10
    Join Date
    Nov 2016
    Location
    New Mexico
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    Thanks, gentlemen.

    I get it!
    Will not worry about my radio.
    Our most important shop tool is the pencil sharpener!

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