We’ve spoken quite a bit about the benefits of USB 3.0 in recent months. Its high rate of data transfer, backward compatibility with previous versions, and overall low cost are still very compelling arguments for the interface. However, many Mac mini 2012 users (and, to a considerably lesser extent, other 2012 Mac users) using USB 3.0 devices have experienced random dropouts or even outright loss of the use of Bluetooth mice and keyboards.
The cause of this is somewhat technical. For those so inclined, you can peruse this white paper written by the USB Implementers Forum for the full details, but the practical upshot is that the signal from USB 3.0 devices can interfere with the 2.4GHz frequency of Bluetooth. The unfortunate result is dropped or lost signals at distances as near as five feet, compared to the normal 20-30 foot reception range of Bluetooth devices. This interference increases the further away from the computer the Bluetooth device is located. At the same time, it was noticed that the further away from the Bluetooth antenna the USB 3.0 device is, the less severe the interference.
Unfortunately, this is the direct inverse of how many Mac mini users are using their computers. Many users have their USB 3.0 devices immediately next to or stacked on top of their minis, taking advantage of the Mac mini’s small form factor. While this may be problematic enough for desktop use, those using their Mac minis in home theater setups will likely have their keyboards and/or mice across the room from the mini’s location, exacerbating the Bluetooth problem.
As the Newer Technology miniStack is designed to for use with the Mac mini, this has obviously caught our attention. We set out to find a resolution to the problem – one that fixes things not just for the miniStack, but for all USB 3.0 drives used with a Mac mini.
As it turns out, it seems to be just a matter of protecting the Bluetooth controller card from the USB 3.0 interference. On the Mac mini’s Bluetooth module, there isn’t a whole lot of shielding to protect against this interference – just some small metallic stickers. By wrapping a special foil around most of the Bluetooth controller card (effectively putting a larger shield on the module), we have substantially improved functional Bluetooth range to about 20 feet, though this can vary with each individual setup, dependent on a number of factors, including drive positioning, quality of cable shielding, and number/type of Bluetooth devices being used at once.
The brief “first look” video (not to be used for actual installation, see below video) above both illustrates the problem and that the solution isn’t particularly difficult to apply on your own. Actually, the most involved part is getting inside the mini itself. Unfortunately, you’ll need the proper EMI shielding foil. That means you cannot wrap the controller card in a layer of Reynolds Wrap or you face the very likely outcome of shorting out something.
Upon further testing, the double-side shielding of the Bluetooth module shown in the “first look” video was found to be extraneous. The proper materials and the complete, step-by-step how-to video are listed below:
Shielding Kit: http://eshop.macsales.com/item/OWC/DIYIMM12BTS/