When I Transmit my the display shows my Voltage Drops Shawn June 30, 2016 21:40 Updated A voltage drop during transmit is normal on the SR-655HPC, SR-955HPC & SR-89MC. Related articles How do I calibrate the SWR meter on my radio? My 655hpc has a D.C. Low on the screen. What does this mean? Do i need to hook it up to the laptop to change it so it shows volts? Comments 0 comments Article is closed for comments.