RD68 VHF
40
E03912 Issue 2.0
The antenna is connected to the radio using a standard PL259-
type connector as fitted to most marine antennas. If fitting to an
existing antenna, check that the contacts are not corroded before
connecting, as this will affect the quality of the signal. Ensure
that the retaining collar of the antenna plug is securely tightened
to prevent accidental disconnection.
For NMEA interfacing to an external navigation source (e.g. a
GPS, Loran or chartplotter) the RD68 is supplied with a 1 m
cable assembly which plugs into the lead at the back of the
radio. The other end is connected to the navigator as follows:
Wire color Navigator connections:
Red NMEA OUT Data (+)
Blue NMEA OUT Common (-)
Fig 4.5 - Linking to navigation source
Red -
Data Out
Blue -
Common
Note If the navigator does not have a dedicated NMEA common ter-
minal, the blue wire should be connected to the 0 V terminal of
the navigator.
The extension speaker socket takes a standard 3.5 mm jack plug.
The speaker used must have a minimum impedance of 8Ω.
4.2 Antenna installation
The most important factor in the performance of the radio will
be the quality and positioning of the antenna. Most recorded
problems with VHF radios are related to poor antenna siting,
faulty cabling, poor quality cable joints, and low voltage supply.
Even a VHF as highly advanced as the RD68 cannot compen-
sate for these factors. Therefore, when replacing an existing
VHF installation, it is important that the antenna is thoroughly
checked for any faults or damage before use.
As the range of VHF signals are governed by line of sight (see
section 5.3), the antenna should be placed as high as possible,
while remaining clear of any metallic objects that could influ-
ence the resonance of the antenna.
