mode is used to enable computer analysis of bat calls as an aid to identifying
species. Using time expansion a bat call is recorded and played back at
a reduced speed. With the Tranquility II you have a choice of playback speed,
either ten times slower ( ÷ 10) or 32 times slower ( ÷ 32).
The played back signal is recorded on a conventional tape recorder for subsequent
Use the ÷ 10 playback for computer work and ÷ 32 playback
for human listening.
The Tranquility II recognises a bat call and automatically starts a recording
and playback cycle at your selected speed. The length of the recorded time
is 1280ms, that is 1.28 seconds of bat call.
As an example of time expanded bat calls consider the calls from a Noctule.
They tend to be split into three sections.
The first section is a signal of approx. 35kHz sweeping down to 25kHz in
The second section is a silent gap of 5ms.
The third section is a signal of 25kHz sweeping down to 20kHz in 10ms.
The sounds of this signal is quite different to the ‘Click’ sounds from
a heterodyne detector.
If ÷ 32 playback is selected the loudspeaker
output will be a sweep of 1kHz to 780Hz in 320ms, followed by a silence
for 160ms and finally a sweep from 780Hz to 625Hz for 320ms. The sound is
quite spectacular and resembles a whale call ( that is a speeded up whale
call ) and is slightly unnerving.
used in this mode the Tranquility behaves as a conventional detector &
is tuneable over the ultrasonic frequency range 12kHz to 120kHz. This range
is suitable for all UK and European bat species.
When used as
a heterodyne receiver the TIME switch must be set to a TUNE position. The
tuned frequency is displayed on a large seven segment LED display. This
display is very accurate due to the use of a crystal controlled time reference.
frequency is adjusted using a single turn potentiometer & the peak power
frequency of calls can be quickly determined. Very useful for example in
distinguishing between 45kHz and 55kHz Pipistrelles.
II has an inbuilt loudspeaker. Alternatively, a low impedance headphone
may be used. Insertion of a headphone jack into the HD jack socket will
disconnect the internal speaker. For stereo headphone both earpieces
The REC output
jack socket is used for connection to a tape recorder.
:- four AA size batteries. To change batteries remove the bottom cover.
: The Tranquility II is guaranteed for 1 year, provided the detector
has not been physically damaged. There are no user replaceable parts other
than four batteries which are replaced by removing the bottom cover.
Expansion Mode :- Frequency range 10kHz to 200kHz.
Record time 20ms, 40ms, 320ms, 1280ms at 200kHz bandwidth.
Sample rate 409.6kHz.
Playback rate ÷10 ( for PC analysis ), ÷32
( for human ears ).
Record/playback sequence automatic.
Mode :- Tuning range 12kHz to 120kHz. Bandwidth ±3kHz.
type. Single wideband capacitive.
Three seven-segment digital 9mm LED.
jack connections :- a) HD stereo headphone socket. b) REC tape recorder
control. Single turn potentiometer.
:- x 4 AAcells. Battery life approx. 35 hours.
loudspeaker. Maximum audio output power 400mW.
knobs. Collet types.
Purpose built ABS 4mm thick.
weight 500gm (with batteries). Size 95 x 154x 36mm.
detector is not water proof, and should be protected from rain. Any
water on battery terminals will cause corrosion.
: (U.K) £439.00
plus registered* post & packaging (£7.20)
* Royal Mail special delivery insurance to stated value.)
price is valid until 30th