Arcing Alarm - microHAM SMORF Manual

PSK IMD ALARM is special, advanced type of the alarm. SMΩRF makes background DSP analysis on the signal
receiving from the sensor all the time, and when finds PSK idle tone pattern in incoming samples, measures its
spectral purity. Based on these results can trigger special, PSK IMD ALARM.
PSK IMD ALARM has just one, WARNING level, there is no reason to make more levels of importance. There is
just one additional settings which allows to set alarm level based on measured PSK IMD levels.
CONTROLS:
PSK IMD
1.
Sets IMD level in dB which causes alarm when exceeds. Range is from -45dB up to -15dB.
For those not familiar with IMD figures, lower the IMD number (more negative) means nicer output signal.
We recommend to set alarm to -25dB level at least.
ARCING ALARM is another special, SMΩRF's unique advanced type of alarm. Of course, detection of real
arcing with just sensor is not technically possible but it is possible to detect side effect of the arcing and it is short
lasting sudden change of impedance. Thanks to high sampling rate and CPU power, SMΩRF can detect these
sudden changes on every sample and therefore detect changes lasting just several micro seconds. And it is
exactly what ARCING ALARM does. If SMΩRF detects sudden impedance change causing SWR to jump above
apx. 5, it activates ARCING ALARM. With alarm enabled, it is possible to catch even slightly hot switched relays,
poorly made or weakly tightened connectors, feedline problems or poor bonds at the antenna.
ARCING ALARM has no settings, it can be just enabled or disabled. When enabled, we recommend to let it
break your TX path (TX BREAK = YES) and reset by PTT or MANUAL, because tripped ARCING ALARM means
that you have some serious problem in T/R timing, transmission path or antenna, which sooner or later results in
some kind of damage.
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ALARM 1 MENU – PSK IMD ALARM
ALARM 1 MENU – ARCING ALARM
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