signal. Its basic display format is a spectrogram plot of signal level versus
frequency versus time in which the signal at frequencies from 17kHz to
120 kHz, over a 10 second time period, is plotted using a variable color
scale to represent spectral intensity.
BatScan can be used for recording, either direct from the
Duet
or from
any ’line’ source e.g. MP3, MiniDisc, tape etc. Files can be monitored
and saved. With the mouse or ‘hot keys’, files can be opened as a
spectrogram and calls analysed for shape, frequency range and interval.
A ‘zoom’ function is incorporated for closer scrutiny of calls.
Furthermore, by clicking the mouse button, over a single call, a readout
of time (milliseconds), frequency (Hz) and sound pressure level (dB) at the
position of the mouse pointer (cursor) is displayed, at the bottom of the
screen. A coordinate grid can also be added or removed by clicking the
“GRID” button at the bottom right of the display.
If you have made recordings in a compressed format (MP3 etc.) you will
need to convert them to .WAV files before they can be analysed.
MP3 players usually come with appropriate software for this. Sonagrams
can be saved, imported into reports or printed.
THE NEED FOR PRACTICE
It is very important that you get used to using the bat detector and
recorder, before expecting perfect results and definitive recordings.
Just as you would have to get used to using any other sophisticated tool,
you will need to practise. Firstly, get used to plugging in your recorder,
headphones etc. in daylight, as you will find it very difficult to set up your
system and adjust recording levels, whilst holding a torch, in the dark.
Once the
Duet
has been connected to your recorder and the record level
set, no further adjustment will be needed. Just use the pause button on
your recorder, in between recording episodes.
Because the
F/D – het
output is at a fixed level, turning the frequency
tuning control of the
Duet
, whilst recording, will not affect the recording
level. However, only bat calls whose frequency is within the set frequency
band of the heterodyne will be recorded (on the right channel), but all
bat calls will be recorded on the left channel as frequency-divided calls.
Moving the volume control will only affect the monitor speaker output and
not the recording.
Bat
box
Duet
is guaranteed for 12 months from the date of purchase
against faulty manufacture. However you can expect many years of
excellent service, if the unit is treated with care.
Make sure that the detector is switched off before replacing it in the case
provided. Remove the battery when storing the bat detector for more than
two weeks.
