“No, I’m not crazy and yes, this story is about an iPhone running on T-Mobile’s 3G network. Yes we’re talking 3G here because only the iPhone 4S really supports what T-Mobile quantifies as 4G anyway. A small, unknown factoid about how T-Mobile is handling some of its spectrum refarming is that in certain parts of the country, they are using the 1900MHz band (known as the PCS band) for HSPA+,” David reports for TmoNews.

“We’ve come to expect that any time we’re talking about T-Mobile’s 3G and 4G phones, we’re talking about phones that operate on T-Mobile’s AWS band of 1700/2100,” David reports. “Well, depending on the part of the country we’re discussing, T-Mobile is utilizing spectrum on the 1900MHz band and because of this some unlocked iPhone users are picking up 3G signals.”

David reports, “Nevada, parts of Northern California and the Pacific Northwest are also seeing some pockets of 1900MHz spectrum refarming for HSPA+. There are other parts of the country T-Mobile can refarm the 1900MHz spectrum but, the focus is on the Pacific Northwest, Nevada, Utah and California for right now from what we’re told. We should emphasize and emphasize greatly that this post does not mean that all of the aforementioned areas are seeing this refarmed spectrum, just pockets inside those areas.”

Much more in the full article here.