CCWN 75:34 
                                                                  
                         Waveforms indicating                     
                        defective devices                         
                                                                  
           The proper waveform should approach an ideal square
wave. small disturbances or transients on the tops of pulses can
be tolerated. The scope will also be of value in detecting any
60Hz power hum or TTL interference riding through on basic power
or control cables.           Bench Testing: The operation of each
element of the system should be checked prior to operation of the
entire system as an amateur CCW station. A borrowed oscilloscope
and frequency counter that can read signals in the 80 meter range
will speed testing. However, only a VTVM and the station receiver
are required.           The Frequency Standard: Bench testing
here is confined to checking the output of each IC with a scope
to insure that it is clean and has good waveform characteristics.
Without a scope, each of the markers can be heard on the station
receiver, with the exception of 'he 40 Hz marker, which can be
tested with the keyer. The standard should be run continuously to
allow thermal stabilization. Adjust the standard as closely as
possible to WWV. Normally it can easily be adjusted to where
there is a beat every 10 seconds that can be observed on the
station receiver. Some experimentation with temperature
compensation capacitors may pay dividends, although the unit
pictured did not require additional work in this area. If the
standard's regulated +5 volt supply is used to power other
equipment, such as the stabilizer, insure that the DC does not
have an AC or pulsating TTL waveform riding on top of it.         
 The CCW Keyer: The keyer should be set up for operation in the
non-coherent mode, using the internal clock of the unit. Proper
operation may be observed by setting the speed to a low rate
(approximately 3 wpm), and activating the paddle. At this slow
speed, the relationship between the enable signal supplied by the
operator and the generation of Morse characters in step with the
clock rather than the enable is easily observed. With the 40 Hz
sync signal from the standard applied and switch S2 in the CCW
position, these same characteristics will be observed, with the
Morse characters at a 12 WPM rate. This particular circuit will
hang up if both the dit and dah enables are simultaneously
grounded. This may be easily cured by a momentary short from Vcc
to ground, restoring operation. Use of a modified semi-automatic
key as shown in the photo will preclude simultaneous dit and dah
enables from being sent to the keyer. A little sending practice
will be in store for most operators, especially if a non-coherent
keyer has been used by the operator for several years.          
The Frequency Stabilizer: The frequency stabilizer is checked by
setting up the station receiver, a VTVM, the frequency standard,
and the TEN-TEC. The isolation amplifier should also be inserted
in the line, but is not absolutely required for testing of the
stabilizer. The stabilizer requires inputs of 500 Khz,