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LOW POWER ALARM is a second common alarm type. Same as SWR alarm, also LOW POWER ALARM has
extensive settings, allows to set three different POWER values to trip three alarm levels (WARNING, ALARM,
FAULT) for each band separately as well as provides two power ranges where different power levels can trip
different alarm levels.
With low power alarm it is important to realize "inverse effect" which can be at the beginning bit confusing
because as power is decreasing, higher alarm level is tripped. Lets take again 160m example for explanation.
You operate barefoot with 100W transceiver, and also use an amplifier which needs to be driven by at least 50W
to get 1200W output on 160m. If PA is over driven it starts to generate unwanted IMD products, when it is under
driven it generates less power than desired. LOW POWER alarm can take care of under drive.
Maximal POWER UP TO value is set to 48W, W-PWR is set to 45W, A-PWR to 40W and F-PWR to 35W. It
means if power is above 48W, SMΩRF will not generate any LOW POWER alarm, but if power is lower and is in
range from 45-48W, it generates WARNING. In range from 40-45W it generates ALARM and in range 35-40W
FAULT. Below 35W it again doesn't generate LOW POWER alarm. This first range is useful for low driving
power alert when amplifier is bypassed if you are using only one sensor behind power amplifier. If you are using
two sensors, one in front and one behind the amplifier, alarm is active all the time.
Second range, maximal POWER UP TO is set to 1150W, W-PWR to 1100W, A-PWR to 900W and F-PWR to
200W. While power will be larger than 1150W, everything will be OK and no LOW POWER alarms will be
generated. However, if power drops and be in between 1100-1150W, SMΩRF will generate WARNING
indicating slightly mistuned or under driven amplifier. If drops even lower and be in 900-1100W range it will
generate ALARM for higher attention (ALARM level is set to generate display alert) and if drops even more and
be in range between 200-900W it generates FAULT indicating seriously mistuned amplifier. Since no LOW
POWER alarm is explicitly dangerous, TX BREAK is disabled for all levels, but FAULT level reset is set to
MANUAL to keep alarm pop-up window on the screen to not miss it.
CONTROLS:
POWER UP TO 1
1.
Sets the highest power for the 1
POWER UP TO 2
2.
Sets the highest power for the 2
3.
W-PWR
Sets the second margin for the WARNING alarm level. Value has to be lower than the power value in the
POWER UP TO cell.
4.
A-PWR
Sets the second margin for the ALARM level. Value has to be lower than the power value in the
WARNING cell.
F-PWR
5.
Sets the second margin for the FAULT alarm level. Value has to be lower than the power value in the
ALARM cell.
Hint:
If you want to turn some importance levels off, set both margins to the same value. For example, if you don't
want to generate alarms for first two importance levels (WARNING, ALARM) in the first power range, set
POWER UP TO and W-PWR margin to same value as has A-PWR, i.e. 40W. It will looks like 40/40/40/35W and
only FAULT will be generated in range from 35-40W. Or you can set 40/35/35/35W, than only WARNING will be
generated in range from 35-40W.
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ALARM 1 MENU – LOW POWER ALARM
st
RANGE
st
power range down from alarms will be generated.
nd
RANGE
nd
power range down from alarms will be generated.
61
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