To my knowledge, 4G is a term for speeds of a Cellular Service, correct?
My point being, unless the dongle links in directly to your cell service, you will need to connect to a WiFi hotspot device, from your Cell Phone provider, or activate the feature on your smart phone (if it supports it). You NetGear WPNT834 lets you connect because it is still part of a network... The network just isn't connected to the internet w/o a Modem. The Router will not have anything to do with connecting to a 4G internet signal. If it is one of those devices such as the dongle for the "Clear" internet service or one of the other "Get internet with this USB device", check the carrier's actual coverage, and read the instructions, you must have done something wrong in the initial configuration.