I recently got a TP-Link TL-MR3220 Router. Every 30 minutes or so, with the dongle in, it keeps dropping the connection. With the dongle directly in the laptop the connection is stable and long-lasting...hours. the router is only 2 meters or so from the laptop and the signal is excellent...Tx is on high and I've tried different channels. The 3G base station is in line of sight and only a couple of hundred meters away at most...75+% signal strength, 6-10Mbits/sec D/L and 2-3Mbits U/L.
I've extended or removed idle times to no avail. There's quite a few parameters to alter in the router settings but I'm dumb in this area.