Instead of doing that, I'd simulate "network loss" by substituting a 50 ohm dummy load for the output antenna. This assumes that it is a connector, not soldered

Instead of doing that, I'd simulate "network loss" by substituting a 50 ohm dummy load for the output antenna. This assumes that it is a connector, not soldered right to the board. This way, there is no "fault" other than not being in a cellular-coverage area.