This is a working vintage direction finder for marine navigation and other applications. The volume knob causes static noise when turned but is fine once set. I think all the pots need cleaning I have powered the unit with both internal battery and external 12 VDC supply and both work fine. I only have AM and FM stations around me and both of those bands play just fine. I was also able to directionally locate the radio station transmitter about 2 miles away from me with ease. The white ring rotates to match your compass heading then you rotate the large knob on top to find the direction of multiple fixed radio sources and you use this information to caculate your position. The meter light is also working.