Battery charging systems
Charge regulator
Instrumentation
Accessories
Bonding
Additional information for suppression of Toyota Land Cruiser’s with vibrating reed
oil pressure sensors
Alternator or generator
Audible as a whine - frequency dependant on engine speed.
Fit an MAR-60A noise filter as supplied in this kit in series with the main charging output of
the alternator. If a satisfactory earth point cannot be found on or immediately adjacent to
the alternator then the alternator/filter connection should be screened.
Generators are treated in the same way as alternators.
Audible as a 'sizzling' noise above engine idle speed. The alternator/regulator control
('field') wire should be removed from any other wiring by replacing with screened wire.
Capacitors should not be connected between this wire and ground as they may damage the
regulator.
Some vehicles use thermal chopping regulators and/or sensors within their instrument
systems. These may be heard as a noise similar to the charge regulator which starts 5 to
20 seconds after the engine is started. This can be suppressed using capacitors on the
supply side and screening on the switched side of the device.
Windscreen wipers, fans, and all other electrical accessories should be checked to ensure
they do not contribute RF noise. They can be suppressed using MAR-ACE filters or
capacitors and the installation method given in the MAR-ACE application note.
All metal objects on a vehicle or vessel should be bonded to one common earth with reliable
connections. Ensure that the body of a vehicle is connected to chassis by-passing any
rubber mounts that may be present. Heavy duty earth straps are supplied for this purpose.
Many Toyota Land Cruiser’s have a vibrating reed oil pressure sensor. This unit generates
square waves which cause severe interference over the entire HF band. The oil pressure
sensor is usually located on the right hand side of the motor at the rear and down low
looking from the front of the vehicle. It is a circular device coloured dull yellow with a single
electrical connection on the end. To suppress this unit a 0.47uf single ended suppressor
should be used. (Supplied in this kit). Usually there are no bolts available in the area to
attach the earth side of the suppressor. If this is the case a 50mm hose clamp (also supplied
in this kit) should be fitted around the oil sensor body. The earth lugs on the 0.47uf
suppressor should be fitted under the clamp and the clamp tightened. The flying lead of the
suppressor should then be connected to the electrical terminal on oil sensor.
For more information regarding suppression refer to the Mobile installation section.
BARRETT 950 HF TRANSCEIVER
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