I have several pieces of gear which use ADAT / Toslink cables, including my A & H console and RME 9652 card. I am aware that fiber optic cable has a minimum bend radius (MBR) to prevent damage.
Are there general guidelines as to what this radius is, in the absence of data from a manufacturer's site? I have read a "recommended MBR" is 15 to 20 times the diameter of the cable itself. To me, this seems reasonable, but I would like to know what experiences others have with this, and perhaps sources of more information.
Post by Michael Lawrence on Aug 28, 2018 22:46:59 GMT
Hi Starliner- Welcome.
ADAT/Toslink /Lightpipe cables are glass (good ones) or plastic (cheap ones). Either way they're not super flexible and so you're right to observe some caution here. As a very general guideline, I wouldn't want to coil them tighter than coils about 12" in diameter. I'm not aware of anything published specifically by the manufacturers.
I work as an engineer in AV contracting. And fiber is quickly becoming a necessity in our world. My understanding of bend radius is that it has very little to do with the strength of the fiber. I have watched people wrap this stuff around pencils and insist that this wont break the fiber. I personally have installed fiber in a situation where the bend radius was around 2-3" and it worked just fine.
The minimum bend radius is really the minimum radius at which the fiber can be bent and the light can still travel down the fiber properly. When the fiber is bent, the light is reflected off of the outer diamter of the fiber. If the bend radius is too great, the reflected light will not continue down the fiber.
Manufacturers such as Belden and Mohawk give minimum bend radius specs. But I can't say that I have ever seen a patch cable have this spec called out.
My opinion.......if your passing signal, then you are okay.
Post by Michael Lawrence on Sept 13, 2018 15:32:18 GMT
Interesting...I'm most familiar with the term "Bend Radius" in the rigging sense, of strength lost in a rope or wire rope by bending it. The wikipedia entry for the term addresses fiber optics specifically, and it seems that both the physical durability and the optical transmission are of concern.