A: You have the "Battery Save" turned off. See page 26: Press and hold "Display" for 3 seconds until "B.SAVE" appears on screen. You just gained 25 hours of life.
Let’s open the virtual manual. Here is a breakdown of the critical sections every owner must read. radio shack dx-390 owners manual
While the "M" is flashing, enter a memory location code (1-9 or 01-09 for SW). The display will confirm the saved location. 4. Advanced Reception Features SSB/CW Reception: For amateur radio or utility signals, turn on the BFO switch and use the BFO Fine Tuning knob to clarify the signal. Bandwidth Filter: WIDE/NARROW A: You have the "Battery Save" turned off