from the manual ...
"6) MON/ 1/25 Key5) WX/INT key
-. When WX/INT key is pressed and released, Alarm 1 is heard and Working CH
/Weather CH are toggled each other.
-. When WX/INT key is continued to be pressed for more than 2 seconds, Alarm 1 is
heard and frequency selection mode(US,International or Canadian) can be
changed. There are 3 types of frequencies selection modes,US,International and
Canadian. The frequencies selection mode is changed like USA--CAN--INT.
-. While the monitor operation is in use,Dual monitor and Triple monitor can be
on International, CH 78 sends at 156.925 and receives at 156.875 !!!
on US mode, CH 78 sends and receives at 156.925
sounds like you've got it in international mode and need to switch to US mode by using the WX/INT key