I have been using the WISMO228 with poor results so far. First, device version lists as B11e0gg. The first problem is that the device parameters do not match what’s listed in AT Command Manual for L20 at all. This device doesn’t even support RTS/CTS at all. If you query for supported modes for settings such as AT+ICF AT+IFC, they don’t support what’s listed in the manual. Next is terrible reception with 1/4 Wave Dipole Antenna. The device hovers at 0 bars with just enough signal to get a network registration and then drop it and repeat. Four different cellphones on the same carrier sitting next to it have from 3-5 bars. Using the SIM from one of the phones has no effect.
So, am I using an old module? I just received it from a Sierra distributor a few weeks ago. And has anyone else had the signal quality issue? Any antenna recommendations to improve reception? The device is cost sensitive, so it would have to be passive.