Setting the stop frequency at 12200 should find a transponder at 12189 because 12189 is less than 12200.

Setting the stop frequency at 12050 should not allow a transponder at 12189 to be registered. Here are the code lines in the blindscan plugin that would not let that happen:

if freq >= self.blindscan_start_frequency.value and freq <= self.blindscan_stop_frequency.value and symbolrate >= self.blindscan_start_symbol.value * 1000 and symbolrate <= self.blindscan_stop_symbol.value * 1000:
add_tp = True
else:
add_tp = False