8.ta signal on the area I am is not picking up well,so there was a day when the 8.ta sim picked up mtn signal on the modem, then signal was browsing proper and when it goes to the 8.ta signal the connection is not proper, Now the 8.ta sim card on the modem I am using is not picking up the MTN.SA signal. How do I make it use this signal permanently, I am using mdma with vodafone modem. I want the 8.ta sim to use the mtn signal when I use it, what's the procedure on doing these, I am on prepaid sim.