I have an unlocked verizon iphone 5 on straight talk with the tmobile sim (yes the verizon iphone can take a sim). I originally had the straight talk att sim but switched because I could not get service in my house on their 3G network. Just 1 bar. The ATT sim now has pretty good 4G LTE coverage in my area. Would being on the 4g LTE improve call signal strength over what I saw with tmobiles 3G or will the phone get the same number of bars with either?