Control Description
PWR
This button is used to power-up and power-down the amplifier, as well as several secondary
functions. To power up the amplifier, briefly press the button. The display will illuminate and
a sign-on message will be displayed:
JUMA-PA100 1.05c
OH2NLT OH7SV
After a short delay, the main screen will be displayed, as shown above.
This button now has assigned to it the cancel alarms function, which takes priority. This is to
make the alarm system consistent with the Juma TRX-2, whose alarms are cancelled with this
button. In the event an alarm cannot be cancelled, press and hold this button for an emergency
shutdown. No user settings will be saved, the power latch signal will be immediately
dropped.
UP/DOWN
These buttons are used to increment/decrement the various user settings, depending upon the
current operating mode. In the normal mode, these buttons alter the gain settings of the
amplifier, as shown by the G1 – G4 indicators on the display. G1 is the lowest gain, and the
gain can be increased in 1dB steps. In fact, the “gain” changes are simply an attenuator being
switched in and out of circuit, but it is convenient to think of this in terms of overall gain.
DISPLAY/CONFIG
This button has two functions. In the normal mode it allows the user to display a number of
internal parameters. From the normal display, a single push will show the current output
power. The next push will display the SWR, followed by the supply voltage, the amplifier
current, and finally the temperature in either EC or EF.
If the button is pressed and held, this will invoke the User Configuration mode, which is fully
covered in a later section. To exit from the User Configuration mode, press and hold the
button until a beep is heard, whereupon the normal display will return.
OPER
This button is used to place the amplifier in either the standby mode or the operate mode. In
previous versions of the firmware it was also used to cancel alarms, this function has now
been moved to the PWR button.
With this firmware revision the amplifier will always power up in the standby mode as a
precaution, except when the System Setup is selected, when it will power up in the operate
state.
In the standby mode the signal path is straight through, with neither filters nor attenuation
present. A connected transceiver will be able to transmit and receive directly to the connected
antenna. The metering functions of the amplifier will operate to show the output power and
SWR, although at low power levels the accuracy is somewhat reduced.
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