Me too. My single biggest (if inconsequential) mistake was at a practise, setting up recording of a punk band called the Seers in the mid 80's. So many things to think about, I miked a hi-hat beside the thing, failing to consider what happens when the air rushes out of the closing hat! Mortifying... That one moment made me very cautious about trying to minimise errors when I dare to commit any kind of opinion.I already knew some electronics, even then, but that mistake was a doozy, plain and simple.
About the phone lines, that's interesting, I was aware a lot was pioneered by them, but never of how much. I did learn fairly recently that RF engineers have only reluctantly come to see balanced lines as better in many cases than coax, again, without any shielding! I think in this case it is the highly precise making of twisted pairs in 'CAT5' cabling that has led to this discovery for antenna wiring.
CATegory anything was a pipe dream back when At&T ruled the roost. Heck they'd run phone lines on barbed wire if it was already on the fence. Made calling the cows home a lot easier. At best I'd guess most telco twisted pairs might come in at CAT 2 or 3 at best. Then when you got to the wiring closets all bets were off. Magic.
My last studio installation I ran shielded CAT 5 in multiple bundles from the centrally located equipment rack area to all the studios and control rooms. I used it for analog balanced line level and AES digital audio, which in our world is also balanced, and Ethernet for computers. None of it was originally Audio Over IP as is the trend now. It was, for me experimental at the time. Of course I hedged my bet by running a few multi-pair of bonafide digital audio cable. So if the whole idea tanked, I could jumper it over to the good stuff and just use the CAT5 for non-critical stuff. Again, I got lucky, though the Director of Engineering shot me a quick stink eye when I first proposed it.
