User's Manual

7.2.11 Cable strain relief

Once all the cables have been run to the appropriate peripher-

als and connected to the transceiver unit they should be

secured to ensure that they are not snagged or exposed to

excess strain.

Screw the strain relief tabs to the cable exit port on the trans-

ceiver unit using the screws supplied and secure the cables to

the tabs using tie wraps as shown (Fig 7.14) -

RS87 VHF

Part No. E04297

Replace the terminal cover and secure by tightening the retain-

ing screw.

7.3 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 sup-

ply. Even a VHF as highly advanced as the RS87 cannot com-

pensate for these factors. Therefore, if 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 8.3), 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.

The most popular antennae for marine use are 1m (3ft 3in)

long. On sail boats these are usually mounted on the mast-

head, where the length of the antenna keeps it clear from the

navigation lights and windvanes etc. This type of antenna can

also be mounted on the cockpit roof or garage of power boats.

Longer whip antennae are recommended for larger boats -

these radiate the same total power as smaller antennae, but

concentrate it into a narrower beam, which is advantageous on

a tall mast at extreme range where concentrating the available

power into a narrow horizontal beam becomes more impor-

Fig 7.14 - Cable strain relief