Connecting The Radio - Uniden UM425 Owner's Manual

Installing the Hardware

Connecting the radio

To operate correctly, your UM425 requires two electrical connections:
• providing it with power from the boat's electrical system
• connecting a VHF-FM marine antenna to the antenna connector
Power supply requirements
Nominal 13.8 VDC power supply with
a negative ground (11.7 VDC to 14.3
VDC).
Power leads should be kept as short
as possible. A direct connection to the
power supply is ideal.
Minimum of #14 AWG copper wire for
extensions up to 20 feet, 12 AWG wire
for extensions from 20 to 35 feet, or 10
AWG wire for extensions from 35 to 60
feet.
13.8V DC
VHF antenna requirements
Male PL-259 connector
50 Ω impedance
Minimum 4 foot, 3 dB rated antenna for
sailboats or 8 foot, 6dB rated antenna
for powerboats
Minimum RG-58 lead-in wire for antenna
leads up to 20 feet, RG-8X for antenna
leads from 20 to 35 feet, or RG-8U for
antenna leads from 35 to 60 feet.
Power
connector
E-44
Red wire
Black wire
Power
cable
(+)
(-)