3 Replies Latest reply: Aug 3, 2013 6:26 AM by HenryS
HenryS Level 2 Level 2 (295 points)

After installing a Sonnet Allegro USB 3.0 card in my MacPro 3,1 (2009+), that generally seems to work OK on its own, I found that the card interferes with trackpad Bluetooth operation severely. Does anyone have any work-arounds on this issue? I will have to return the card if it can't be fixed. I'm told that other cards similarly affect Bluetooth connected device operation and that they are not doing anything about fixing the problem as it is not their issue (does not affect operation of the USB 3.0 connected devices (even though it does produce bus interference in and of itself that in turn causes the problem). Harrumph, says I.

 

I haven't digested the Intel White Paper fully, but Intel suggest using Aluminum foil to mitigate the effect in some way. REALLY???

 

This is the image from their FAQ page on this.

Screen Shot 2013-06-05 at 16.26.27 .png

 

Sonnettech's site referred me to an Intel White Paper describing this issue and pointedly directed me to Apple about the interference problem they claim to be a known issue, here


Mac Pro, OS X Mountain Lion, (3,1) 10GB RAM, 500GB HD+250GB SSD
  • 1.
    mario49 Community Specialists Community Specialists (2,050 points)

    Hi HenryS,

     

    Thanks for using Apple Support Communities.

     

    For more information on this, take a look at this article:

    Bluetooth: Unreliable wireless performance may occur when USB 3.0 external devices are close

    http://support.apple.com/kb/TS4512

     

    Better shielded USB 3.0 cables may also be helpful.


     

    Using USB 3 devices on Mac computers FAQ

    http://support.apple.com/kb/HT5172

     

    I sometimes have difficulty with Wi-Fi or Bluetooth devices when USB 3 devices are attached to my computer.  What could be wrong?

    Some USB 3 devices, hard drives in particular, can generate radio frequency interference that can cause Wi-Fi and Bluetooth devices operating in the 2.4GHz band to have issues communicating with your computer. Do not place hard drives or other USB devices behind the rear of your Mac near at the hinge of your screen. The antennas for Wi-Fi and Bluetooth are located there, and USB 3 devices placed there may interfere with your wireless connections. See this white paper for more information.

    Best of luck,

    Mario

  • 2. Re: USB 3.0 PCIe cards interfere with Bluetooth chip on board MacPro
    HenryS Level 2 Level 2 (295 points)

    mario49 wrote:

     

    Hi HenryS,

     

    Thanks for using Apple Support Communities.

     

    For more information on this, take a look at this article:

    Bluetooth: Unreliable wireless performance may occur when USB 3.0 external devices are close

    http://support.apple.com/kb/TS4512

     

    Better shielded USB 3.0 cables may also be helpful.


     

    Using USB 3 devices on Mac computers FAQ

    http://support.apple.com/kb/HT5172

     

    I sometimes have difficulty with Wi-Fi or Bluetooth devices when USB 3 devices are attached to my computer.  What could be wrong?

    Some USB 3 devices, hard drives in particular, can generate radio frequency interference that can cause Wi-Fi and Bluetooth devices operating in the 2.4GHz band to have issues communicating with your computer. Do not place hard drives or other USB devices behind the rear of your Mac near at the hinge of your screen. The antennas for Wi-Fi and Bluetooth are located there, and USB 3 devices placed there may interfere with your wireless connections. See this white paper for more information.

    Best of luck,

    Mario

    Looks like your advice was spot on, Mario. I found that disconnecting (turning off) my device connected to the internal card fixed the problem with the (Bluetooth wireless) trackpad. SInce the DC is run through the cable, unplugging made the difference. Either end of the cable being unplugged was OK, so guessing that the device itself or the cable was the problem.

     

    Next, I looked into relocating the card reader to see if the interference was reduced by a new location. It still had some issues even when stretched as far as possible from the card, so my thinking was the cable was acting like an antenna, radiating the interference.

     

    As my next step, I will try a device to reduce interference attached to the cable, one or two clip on ferrite core in line EMI filters, this one is sold by Amazon.

  • 3. Re: USB 3.0 PCIe cards interfere with Bluetooth chip on board MacPro
    HenryS Level 2 Level 2 (295 points)

    All these 'fixes' were needed- externally mounting a BT antenna, routing reader's USB 3 cable at right angles to the antenna and using ferrite cores on the USB3 cable- to kill the effects of interference to external BT devices (Magic Trackpad and keyboard devices). Even with that, the RF levels on the BT device when a USB 3 device is plugged in (Card Reader) still vary, degrading the signal. Just not enough to impact operation of the MT device.