The iPad will deliver 73 Mbps LTE. Why not 72?

Apple’s(s aapl) latest bright, shiny iPad has been revealed, and it has Retina display, a faster chip and all sorts of goodies, but for the network crowd only three letters mattered: LTE. And yes, the new iPad will have the latest Long Term Evolution cellular networking standard and will deliver up to 73 Mbps down. Wait — what? 73?
We were puzzled too, since in the U.S. carriers are advertising speeds of 5 to 12 Mbps down and even in Canada (which also got some love today during the presentation), carriers are advertising 25 Mbps, but thanks to Chetan Sharma, a wireless industry analyst, we figured it out. Under the technical specs for the LTE standard, a radio using 2×2 MIMO and 10 MHz of spectrum will max out at 73 Mbps, though, just as with other theoretical peak speeds, don’t expect your phone to actually get anywhere near that ceiling.
And the mystery is solved. Verizon and AT&T are both deploying their LTE networks in 10 by 10 MHz of spectrum, and they will each have two antennas inside the device sending signals to the base station, which does mean LTE may drain the battery on the iPad a wee bit faster. It’s a similar network configuration to T-Mobile’s planned LTE network (although T-Mobile claims its network will top out at 72 Mbps). Regardless, at the top speeds, you’re going to suck through a 5GB-per-month data plan on an LTE iPad in about 10 minutes, going full out.