How do you disable that loss of signal sound?

[Supermanwoot]

Ok this is by far THE MOST ANNOYING THING IN THE WORLD. I have my grad classes all day, inside a classroom that is very much in the center of the building in an area that already gets bad signal reception. All class my phone is going "boop boop beep" ... "beep beep boop" as it loses signal and then regains it. This happens even on silent and even when I check all sounds/notifications and turn all of them off. Right now my phone is inside my laptop backpack (very insulated to deaden the sound) and it is LOUD.
I can't stand it anymore and i dont want to keep turning my phone off ALL DAY because it beeps loudly while on SILENT.

Ok hopefully you understand my rant but yeah this is a terrible/overlooked feature of the phone.

Thanks guys