Elecraft W2 Watt-meter Manual - Manual (Page 8)

8
SWR Alarm Function
If set, the SWR Alarm will cause all the LEDs to flash in unison if the SWR exceeds 3:1 and triggers the relay
that opens the circuit between the center pins of the PTT RY phono connectors. The SWR Alarm function must
be enabled each time the W2 power is turned on.
Send an ASCII character
a to the W2 to toggle the alarm on or off. This may be done using the W2 Utility
program Command Tester screen. The W2 will respond with a1; indicating the alarm is set or a0; indicating the
alarm is disabled. If an alarm occurs, reset the W2 by pressing either the SENSOR or RANGE buttons.
Kit Assembly
Preventing Electrostatic Discharge Damage
Sensitive components in your W2 are may be damaged by Electrostatic Discharge (ESD) in any location or
climate unless you take specific steps to prevent such damage. Many components can be damaged by static
discharges of only a few volts: far too little for you to notice.
ESD damage may not be apparent at first. The damaged components may not fail completely. Instead, the
damage may result in below-normal performance for an extended period of time before you experience a total
failure.
We strongly recommend you take the following anti-static precautions (listed in order of importance) to ensure
there is no voltage difference between the components and any object that touches them:
 Leave ESD-sensitive parts in their anti-static packaging until you install them. The packaging may be a
special plastic bag that allow static charges to flow harmlessly over their surface, or the component’s
leads may be inserted in conductive foam that keep them at the same potential. Parts which are
especially ESD-sensitive are identified in the parts list and in the assembly procedures.
 Wear a conductive wrist strap with a series 1-megohm resistor that will constantly drain off any static
charge that accumulates on your body. If you do not have a wrist strap, touch a ground briefly before
touching any sensitive parts to discharge your body. Do this frequently while you are working. You can
collect a destructive static charge on your body just sitting at the work bench.
WARNING
DO NOT attach a ground directly to yourself without a current-limiting resistor as this poses a
serious shock hazard. A wrist strap must include a 1-megohm resistor to limit the current flow. If
you choose to touch an unpainted, metal ground to discharge yourself, do it only when you are
not touching any live circuits with any part of your body.
 Use a grounded anti-static mat on your work bench.
 If you choose to use a soldering iron to work on your W2 for any reason, be sure your iron has an ESD-
safe grounded tip tied to the same common ground used by your mat or wrist strap.