I found this solution in the evdoinfo forum and it works. This is for VZ Access Manager I have not tried using MBR 1200 and setup for that yet. Open Access Manager Hit keys Ctrl d use password diagvzw go to settings check HDR and save it is probably set Global. This locks EVDO 3G and I have had it connected for 19 hours with 2 MBPS Down and .95 MBPS up with an external antenna. Hope this helps.
Welcome to the family of UML290 owners, you can recognize us by our glazed eye look and imprint of phone on our ear from being on phone with "tech" support so long.
The 3G performance of this modem is flaky at best, the ctrl-d trick will get you along for a while but for whatever reason that seems to degrade over time also. If you have a previous modem you can use I think the others are correct in stay with that. I am in a full 4G area, when it works its awesome but they are really struggling with the network. (It appears they have some serious problems with router configuration within the network. Almost looks like they have the redundancy mapping messed up and packets are looping.)
I hope this helps some of you.
I found the solution to connection dropping problem after 1 week of research and trial/errors.
Step 1: Call verizon support at 866-221-4096.
Step 2: Press 6 for MIFI device.
Step 3: They will ask you to remove SIM card, wait 10 seconds, then put it back in.
After doing this, it never dropped again. The tech person said by removing the SIM, it resets the cell towers it's connected to. He even called me 15 minutes later to make sure. He did say that he did something on his side too so not sure if calling is required.