Doppler Trainer

Doppler Trainer puts you at a sonar operator's console. Learn to hear what a contact is doing, understand why it sounds that way, and put a submarine on the plot. EAR TRAINING Listen to a contact and call its motion: Closing, CPA, or Opening. A closing contact sounds above its true frequency, an opening contact sounds below it, and at the closest point of approach you hear the true tone. Watch the signal on a waterfall or spectrum display and track your score. DOPPLER LAB Choose a frequency, a motion, and a speed in knots, then play the tone. See the source and observed frequencies side by side and hear how higher speed or higher frequency pulls the tone farther from true, while CPA stays on it at any speed. dB LAB Work an acoustic budget. Set source level, ambient noise, receiver sensitivity, and frequency, then drag the range. Transmission loss from spreading and absorption grows with distance until the signal goes from CLEAR to MARGIN to MASKED. Load presets from submarine tonals and blade rate to rain, surf, and shipping noise. TACTICAL FIX Three sonobuoys. One submarine. Choose LOFAR buoys, which report frequency and relative amplitude (louder is closer, no bearing), or DIFAR buoys, which add a bearing to the contact. Listen to each buoy, read its Doppler, place your fix on the overhead tactical plot, set the contact's heading on the compass, and submit. The debrief shows your position and heading error. Enter a callsign to rank your best rounds. BUILT FOR LEARNING • On-screen coaching walks new operators through each mode • All audio is synthesized on the device; headphones help with low frequencies • Works offline. No account, no ads, no data collection Doppler Trainer is an educational simulation. It is not affiliated with or endorsed by any navy or government agency.