[EVO 4G Q&A, Help & Troubleshooting] Blayznaz:
Here's an explanation of AWS:

Originally posted by ChazzMatt on HowardForums.

You can go to any place you wish in the whole world and get a major carrier's phone flashed to MetroPCS - but the phone will still not work in the Metro markets that use AWS frequencies.

See, Metro has CDMA and LTE networks. For now, we are just talking about the CDMA part. LTE is "4G". For this discussion, we are not talking about 4G networks. Verizon also has CDMA (again we are not going to mention Verizon's LTE). Sprint has CDMA (for 4G, Sprint has Wi-Max, but is going to LTE, but for this discussion we don't care.) Virgin has CDMA, because they are a subsidiary of Sprint.

AT&T and T-Mobile have GSM which is the competitor to CDMA.

Now, here's where the rubber meets the road. The "traditional" CDMA frequencies are 800 MHz and 1900 MHz. So, if you lived in a Metro market where Metro uses 800/1900 MHz, which is also the CDMA frequencies that Verizon, Sprint, Virgin, etc also use -- then all you have to do is "flash" (convert) all the internal instructions to point to MetroPCS instead of the original carrier (like Verizon). Your flashed phone will now work on MetroPCS CDMA network. You then have a Metro dealer enter the phone in the MetroPCS system database as an authorized device. You pay your monthly bill and you are good to go. (How many services work with MetroPCS depends on how well the phone was "flashed". The holy grail is talk, text and web. Some flashers only get talk and text working.)

But note the bold parts in the paragraph above. The CDMA frequencies are normally 800/1900 MHz. BUT, to get into some markets, Metro does NOT use the traditional CDMA frequencies. Instead they push a "CDMA" signal on AWS frequencies: 1700/2100 MHz. New York is one of those markets where Metro is forced to use AWS frequencies. If you took a CDMA Verizon phone and flashed it to Metro, the 800/1900 MHz chipset inside would work on Metro's 800/1900 MHz signal (like in Florida) -- but that Metro doe s NOT have that signal in New York. In New York, you would get no signal. However, if you go to another Metro market that uses the 800/1900 MHz band - like Florida - then BOOM, you get a signal on that flashed phone.

MetroPCS has manufacturers make phones specifically for them that have 800/1900 and 1700/2100 MHz frequency chipsets. Verizon's phones (Sprint also) do not have the necessary chipsets inside to work on Metro's AWS frequencies. Verizon couldn't care less about AWS frequencies, and don't have those chipsets in their phones. No AWS chipsets in your phone? Then you won't get a signal in AWS markets.

Here's an analogy...

You car's AM/FM radio picks up the AM/FM band stations.

Your car's radio does NOT pick up police band/emergency services broadcasts. "Robbery in progress" and all that? Why not? Because your car's radio cannot receive those frequencies. Police cars, of course, have radios that receive both AM/FM band radio transmissions AND police band radio transmissions.

A MetroPCS manufactured phone is like a police car. It has all frequency chipsets needed. A CDMA flashed phone only has the "regular" frequencies. In New York, Metro does not transmit on the "regular" frequencies.