Subphone 10 KHz + 30 KHz Subphone Tx 27 KHz + 37.5 KHz Subphone TX Operating Frequency (Single or Double) USB 8.0875 KHz 1 Hz and USB 28.5 KHz 1 Hz (Other frequencies available) USB 25 KHz 1Hz and USB 36 KHz 1 Hz (Other frequencies available) Outlets per Frequency/ Transducer Connections 2 per frequency 2 per frequency Modulation Single-Sideband (SSB) Suppressed Carrier Single-Sideband (SSB) Suppressed Carrier Transmitter Activation PPT (push-to-talk) Microphone 150 Ohm Dynamic PPT (push-to-talk) Microphone 150 Ohm Dynamic Transmitter Power High Power:50 watts RMS Low Power:0.5 watts RMS Selectable by operator 5 watts RMS Pinger 15 m-sec, per second pulse 15 m-sec, per second pulse Receiver Audio Output Power 2 watts RMS 2 watts RMS Receiver Gain Control Automatic or Manual Selectable by operator Automatic or Manual Selectable by operator Nominal Range in Salt Water at Maximum Power 10 km (6.2 miles) at 10 KHz 6 km (3.7 miles) at 30 KHz 3.5 km (2.2 miles) at 10 KHz 2 km (1.2 miles) at 37.5 KHz