10 March 2020 QST www.arrl.org
was not high (around 800 Hz). Similarly, I didn’t hear
a noticeable difference while listening on SSB with a
filter bandwidth set to 2,300 Hz.
I set the upper limit of the filter bandwidth to 5,000 Hz
and tuned in some music on a shortwave broadcast.
There was definitely a difference in the high frequen-
cies of the broadcast transmission, but because the
bandwidth was limited to 5,000 Hz, I didn’t hear a big
difference. While this mode appears to work, I didn’t
find it too useful for typical ham radio modes, which
have limited audio bandwidth.
More useful for some operators is the left-right bal-
ance control included in a recent firmware update.
Accessed from the
OUTPUT SETTINGS
menu, this fea-
ture allows increasing the audio level in one ear or
the other in 1⁄2dB steps to compensate for differ-
ences in hearing.
Morse Code Decoder
Decoded text appears on the left side of the display
and a small audio spectrum scope on the right (see
Figure 9). The received signal to be decoded must
be centered in the spectrum scope.You can do that
by tuning your receiver to the correct pitch, or by
turning the
MULTI
knob to match the Wolfwave to the
received pitch.
The Wolfwave automatically adjusts to the received
CW speed. The default setting allows CW speeds
from 5 to 40 WPM, but you can change the limits
from 0 to 100 WPM. The detection threshold can be
changed as well, which helps with false decodes
from noise.
I found the decoder to be very accepting of off-fre-
quency tuning — the pitch just has to be close to the
incoming signal. In addition to showing decoded text,
dots and dashes are shown at the bottom of the
screen and the measured code speed in words per
minute on the top left corner. If the band is noisy, try
raising the decoder threshold from its factory setting
of 3 dB to perhaps 8 or 10 dB.
CW Regen
CW regeneration is a function that I have not seen
for a long time. Many years ago, the National
Company included a function called Select-O-Jet in
several of its receivers. The circuit gave positive feed-
back on a selected frequency, and in the presence of
noise or other signals, the selected tones would be
boosted by the function.
In the Wolfwave, this experimental function detects
the dits and dahs in the received signal and regener-
ates the CW signal with a clean sine wave and no
noise. The CW tone to be regenerated must be in the
center of the passband, and the trigger level point
can be adjusted from 1 to 30 dB.The output (regen-
erated) tone can be set to be identical to the input
CW tone or offset from it. With a stereo headset, you
can listen to the received signal in one ear and the
regenerated CW tone in the other.
For the regenerator to work, I had to carefully set the
band-pass center frequency to the CW tone I use,
and to carefully limit the input signal to the green
LED range.The CW regenerator works well, but
tuning is critical. Any attempt to change the receiver
frequency by a tiny amount almost always resulted in
loss of copy, requiring shutting the regenerator off
and resetting the receive frequency.
Audio Test Generator
Under
UTILITIES
on the main menu, there is a selec-
tion to generate tones.Turning this on brings up an
audio generator with the output selections of sine
wave, triangle wave, square wave, and two-tone.
Each of these can be set to a selected amplitude and
frequency.
Support and Firmware Updates
The Wolfwave package does not include a printed
manual, but detailed information about setup and
operation may be found on the SOTABEAMS web-
site, as well as a website dedicated to this product
(www.wolfwave.co.uk). In addition to written
instructions, there are tutorials and links to helpful
videos.
SOTABEAMS offers accessories and replacement
cables for the Wolfwave. One that may be useful is
an audio ground loop isolator, which can reduce or
eliminate hum from ground loops. This isolator plugs
in between your transceiver and the filter, breaking
the ground loop.
Figure 9 — The
Wolfwave Morse
decoder screen.
