HTC EVO 4G :: CDMA Network - Searching For GSM Signal?

A friend of mine is a member of the EVO Facebook group and sent me to a link which reads as follows:
"For those of you having battery issues I found a way to Dramatically improve the battery life.
First things first, go into Settings> About Phone> Battery> Battery Use> Cell Standby. Assuming your phone has been on, or off the charger for ~10 minutes, it should show Time Without Signal at around 50%. Next thing, press Home and bring up the dialer. Dial *#*#4636#*#* (Do not press "Call"). After a second, it should bring up the "Testing" menu.

Go into Phone Information, press MENU, and tap "select radio band." You should experience a Force Close, don't panic, this was supposed to happen. Scrolling down shows that the preferred network type is GSM auto (prl). What this means is that even though you are connected to a CDMA network, your phone is trying to find a GSM network, preventing the radio from sleeping, and causing excessive battery drain. Remedy this by tapping GSM auto (prl) and changing it to CDMA auto (prl).

Now your done, your TWS should drop dramatically, and you should experience much better battery life!
Note: You need to do this every time you reboot."
I've changed it on my phone just now and the service still works as normal. I guess we'll see if the battery life increases. If this works and with overclock widget I should be getting some crazy battery life now!