Furuno RC-1800F Operator's Manual page 402

(7) Audio Output
(8) Standard Features
4. ANTENNA COUPLER
(1) Tuning System
(2) Frequency Range
(3) Input Impedance
(4) Antenna
(5) Tuning Power
(6) VSWR
(7) Tuning Time
(8) Dummy Load
(9) Power Source
(10) Antenna BK relay
Internal speaker: 2 W/ 8 ohms
External speaker: 4 W/ 4 ohms
Line output: 0 dBm/ 600 ohms
Scan, Sweep, Noise Blanker, Voice-activated Squelch
CPU controlled fully automatic tuning system
1.6 MHz to 27.5 MHz
50 ohms (viewed from transceiver)
7 m to 18 m wire or whip antenna + wire
10 W
less than 1.5
0.2 to 2 seconds typical (within 2 to 15 seconds.)
10 ohms + 250 pF mounted in the coupler
18 VDC: supplied from transceiver unit
Internal, optional supply
SP – 3D E5632S02D