Hmm I understand dBs just fine, I don't need to understand how to plot a graph of the resistance of some rubbish to install and maintain a network.
I think many people make this mistake when it comes to Computer Science degrees in general. Quite a few people want to be web developers, support staff, network technicians etc. so do a degree thinking it'll be some vocational training directly related to a job. As you've found out, that's not what a degree provides you with.
I think if you get your head down with this course, learn the stuff they're teaching you to a good standard and then apply for the sort of job you're after you'll do much better than if you'd not done it. If you find the right job you'll get training specific to the role and that will build on what you've learnt in the degree. You should then see where it all slots in to place and things that didn't immediately seem useful will probably become near-essential knowledge.
It does all depend on whether you want to know how and why things work to get an in-depth knowledge of the systems you could be designing and maintaining or whether you just want to be told that the red plug goes in the red socket and the power button turns it on.