I've read a lot of the posts here and want to clear up a few of the misconceptions I read here.
Like all current dual-SIM Windows Phones, the Blu Win HD has only *one* radio. Not just one 3G radio, just one radio period. This radio is capable of either 2G or HSPA.
If one SIM is using the radio, then the other cannot. When you SMS yourself, it uses the radio briefly to send, then the other uses it briefly to receive. When one SIM is on the phone, the other can't ring because the radio is in use.
The Blu Win HD is HSPA for one SIM and 2G-only for the other. This isn't speculation, this is fact. It says it right on Blu's official spec list. So, yes, only a SIM on the Rogers network can use the second SIM in Canada. Bellus, Wind, etc., cannot, as they don't support 2G. Telus has no 2G anymore at all, and Bell only has CDMA2000 2G (which they're in the process of decommissioning).
It's no more false advertising to advertise a dual-SIM phone that can only use one SIM at a time, than it is to sell a multi-CD changer that can only play one CD at a time. That said, I get the confusion because there are four kinds of dual-SIM handsets:
- single standby, where only one SIM can access the radio, and you select from a menu which one it is
- dual-standby, where duplexing is used to let the SIMs rapidly alternate which is listening to the radio (this is what all the dual-SIM Windows Phones from Blu are)
- dual-standby w/auto-forwarding, where when one SIM is in use on the phone, calls to the other SIM are automatically forwarded to the other (this is what all the dual-SIM Lumias are)
- dual-active, where there are two radios so both SIMs can do whatever, whenever (this is very, very rare)
The only downer of the Blu Win HD is that it's not 3G on both radios. A 2G-only SIM is virtually useless for many Canadians.