periods of time input voltages up to about +15V, it is unwise to continue to use it if you
experience a significant number of over-voltage alarms.
Under-Voltage
Low input voltages are not damaging to the transceiver, but are worth investigating. If the
equipment is being operated under portable conditions, then it is likely that the power supply
will be a small sealed lead-acid battery. These deep-cycle batteries are a very suitable power
source, but to ensure optimum life they do need to be used in a careful and considerate way.
Most manufacturer’s recommend that the discharge be terminated when the voltage has fallen
to 10.5V. It is certainly very bad for the battery to be discharged beyond this point, and will
greatly shorten its service life.
To maximise the life, the cut-off voltage should be somewhat higher than this, and 11.0V is a
reasonable compromise between maximum operating time and service life of the battery. If it
is discharged down to these voltages it must be placed on charge immediately afterwards or
within as short a period of time as possible. Do not leave a sealed lead-acid battery in a
discharged state, at low voltages a secondary electrochemical reaction occurs which leads to
sulphation, which is not recoverable.
To prevent this, the undervoltage alarm is provided. To give you warning of the approach of
the cut-off threshold, a pre-limit warning is given at a voltage 100mV higher than the preset
threshold. This will display the warning message:
Low Batt Voltage
.
To cancel the warning, briefly press the PWR button. Note however that this warning will
only be given once, and when cancelled will not re-appear. The only way to reset the warning
is to turn the transceiver off and the back on again. If operation is continued down to the
threshold setting, then the alarm will persist, no buttons other than the PWR button, or other
functions will be operative, the only recourse is to turn the transceiver off.
Any or all of the alarms, with the exception of the high SWR, can be disabled, if you wish.
Note that if the undervoltage alarm is disabled, then the pre-limit alarm is also disabled.
45