CCWN 75:53
                                                 
A Portable  CCW TRANSMITTER Chs s Woodson

         The CCW transmitter, I call it model CCW-l, described
here has been used in several versions for experimentation over
the last year. It is powered by a 12 volt automobile battery and
has an output of about a watt.           The transmitter is not
intended for wide duplication as it has severe limitations,
particularly single frequency operation and no provisions for
break-in operation. There is also sufficient feedthrough from the
oscillators to cause receiving problems when the antenna lead in
and the receiver are not well shielded. However, it has been
useful for CCW tests and may serve that purpose for others.       
   The 14,049,000 Hz oscillator is similar to those developed by
K4EEU for frequency standards. It was temperature compensated in
the manner described earlier in CCWN. A small air trimmer is
built in to allow adjustment of the frequency. It gives a range
of about 20 Hz. The short term stability, during a QSO, just
meets the requirements of CCW with .l second mark pulses, namely,
a Hz or two during the QSO. Longer term stability has been
insufficient so the practice is to adjust the oscillator to
14,049,000 Hz before each QSO. The oscillator is adjusted to
frequency by setting the station standard to l kHz and tuning a
receiver to the harmonic at 14,049,000 Hz. The transmitter is
then keyed (with the dummy load on) and the trimmer is adjusted
for zero beat.           The crystal is a high accuracy one from
International Crystals cut for room temperature and 32 ppf.       
   I have used a stabilizer similar to the one I described for my
SB-303 and it holds the frequency much closer. However, it has
not been used in most experimentation and I do not include it
here for simplicity.           The oscillator and first buffer
stage stay on all the time in the interest of stability. The
keyed amplifier was keyed in the collector supply with the
intention of providing as little load change to the oscillator as
possible. I did not try other arrangements as this one worked
satisfactorily.           The keyer I have been using is a
modified accu-keyer which will be described later in CCWN. It has
its own 4 Mhz% independent frequency reference and uses 7490
dividers to obtain the 20 Hz keying reference.