BARRETT 2030 HF SSB TRANSCEIVER
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Coil to Battery Wiring
A low pass filter such as that supplied in the interference suppression kit or similar
should be fitted at the coil end of this wire. The earth connection of the filter should
be short and well-bonded to the coil body.
Battery Charging System
The charging system circuit, consisting of either generator or alternator and a
regulator may also be split into three parts:-
Alternator / Generator to Battery Wiring
A low pass filter such as that supplied in the interference suppression kit or similar
should be fitted to the main battery lead at the alternator. The filter must be rated
for the maximum current available from the charging system. The earth lug of the
filter should be attached to the alternator body or the engine block.
Alternator to Regulator Control Wire (Generator Field Wire)
This wire carries switching pulses that often contribute noise to the receiver.
Suppression using capacitors or filters must not be attempted since damage to the
regulator may result. Separate the wire from all other wiring, keep it as short as
possible and, if longer than about 300mm it should be shielded as described above.
Other Regulator Wires
These are normally adequately suppressed using good low-inductance bypass
capacitors. To be effective, these capacitors must connect to the wires to be
suppressed and to chassis with very short leads. For this reason, the 'pigtail' style
of suppressor capacitor often used with MF broadcast receivers is generally
ineffective at HF.
Other Noise Sources
Electric Motors
(windscreen wipers, fans etc.)
Small electric motors can usually be suppressed with good low inductance bypass
capacitors.
Engine Instrumentation
Certain types of oil-pressure sensors and voltage regulators used in instrument
systems contain a vibrating or thermal cycling contact. These devices can only be
suppressed by isolating and screening or wiring in the same way as described for
the alternator to regulator control wire. Disc ceramic capacitors with short leads
(protected with insulating sleeving) are frequently useful but to prevent damage to
instrument contacts, where the use of bypass capacitors is attempted, values larger
than 1nF should not be used.