I'm not the original poster, but am experiencing the same issues on base. I work in a concrete building next to an exterior wall, but the slow speeds happen even when I'm outside on base. There are no excessive electronics, just standard office computers. It usually speeds back up to normal right as I reach the gate to leave.
My phone also shows 4G and two to four bars of service at all times. But when I actually try to do things on data, it is incredibly slow. It took almost a full minute just to log in to the Verizon site to post this.