So heres the deal, theres a new iPhone out there and its got the new blazing LTE. If you're planning to get one buying from countries which have unlocked options (Canada, Singapore, Hong Kong) doesnt necessarily merit that you'll get LTE compatibility wherever you go.
In the iPhone 5 website, theres a little asterisk there. Pretty sneaky if you ask me, that they have created 2 different models probably using 2 different LTE chips.
GSM model A1428*: UMTS/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz); GSM/EDGE (850, 900, 1800, 1900 MHz); LTE (Bands 4 and 17)
GSM model A1429*: UMTS/HSPA+/DC-HSDPA (850, 900, 1900, 2100 MHz); GSM/EDGE (850, 900, 1800, 1900 MHz); LTE (Bands 1, 3, 5)
- From: http://www.apple.com/iphone/specs.html
So what does this mean? If you're planning to get an unlocked unit from other country, LTE speeds might not be compatible with yours. From Wikpedia, theres a working list of LTE bands per country.
With me residing in the Philippines it seems that the LTE band in the Philippines is LTE Band 1 and 3 (GSM model A1429). But what if im travelling outside? US or Canada perhaps? I think what better way to explain this by plotting it into a spreadsheet.
So, how do you look at the graph? Normally, you would be sourcing your phone from somehere its factory unlocked. Either Hong Kong, Singapore, Canada (or US once they make it available in the Apple Store) So, look for the country where your unlocked iPhone will be originating. Most likely that the iPhone that will be sold there will be using that LTE band (duh). After, look for the country you will be using your phone. For me, I will be looking at the Philippines.
From here, it seems like the Philippines is using LTE band 1 and 3 (A1429) and the countries which will most likely sell an unlocked A1429 would be: Singapore, Hong Kong, Australia.
If you would notice, if I buy myself an A1429.. LTE features might not work when I fly to either Canada or the US. Sad.
Anyway, as a disclaimer, this spreadsheet was compiled September 2012 and may not reflect the changes once new carriers roll out new LTE infrastructure in the future.