Sneaking in a few minutes...
Does the signal strength remain at 100%? Part of my problem was the signal strength wavering up and down. I don't know what the cutoff threshold was, but when the signal was dipping down into the 70% region, I'd lose signal. I seem to have fixed it by moving my wifi router a couple feet closer to the SBT. This is not my cable company supplied modem; it's an after market router.
Appliances, such as microwave oven, fridge, etc. can disrupt the signal. Have you checked for this?
For whatever reason, I had to install the newest SBT update three times before it was happy and stopped asking me to install it - on my Mac Mini and twice on my SBT. I did not check to see if there were three different updates or if it was the same update. In the past, updates have not come along in quick succession, so I assumed this was the same one that failed to properly install.
Here's something really strange: approximately 3 months ago, after many failed attempts to get the SBT to lock onto the wifi signal, I added an empty skandisk (sp?) memory card because my SBT repeatedly told me that was required in order to successfully make the connection. [I don't for one second believe this btw.] I finally did this and after about four attempts at connecting to my Mac Mini via wifi, I succeeded. [Perhaps the voodoo doll I'd made in the SBT's likeness had something to do with it. Fear can be a great motivator.] Why don't I believe the memory card has anything to do with it? Because the SBT recognizes it as a separate storage device that has nothing to do with my wifi connection. My SBT is not accessing the card at all. How weird is that?
Before the latest update to the Mac, I discovered the my LMS was shutting down of its own volition. It had to repeatedly go in to restart LMS, followed by my instructing it to rescan my library of music in iTunes. Updating to El Capitan seems to have fixed this problem.
Okay, I'm out of time again. I hope some of this helps.
Michael
