This quality hetrodyne bat detector is tuned by adjusting the tuning knob to the center of the desired frequency in kHz. The detector in real time plays any ultrasound that is approximately 4 kHz above and below the tuned frequency.This method works by frequency subtraction and only a very narrow part of the spectrum is scanned at any given time, so a tremendous amount information is not detected.

Hetrodynes produce low quality analog output and is not used for detailed computer analysis. However, many people are able to discern different species with practice in areas where there is little overlap in call frequencies. For example, a bat heard best at 19 kHz in the eastern US is most likely a hoary bat, as no other species typically calls that low.

Similarly, an experianced user may be able to group calls by genus to a fair extent, suitable for interperters doing bat walks, or bat enthuesists looking for a low cost acoustic detector. Tone qualities of the output change if the bat is calling above or below the present frequency of the detector. This enables users listening in real time to rapidly "tune into" the bat as it flies by and get a good estimate of the bat's dominant frequency, the basis for species identification.

Please note: hetrodyne detectors -are not- intended for computer analysis and precise species identification. They can be used for passage rates at mine entrances, etc.

Pettersson D200

• Type: Heterodyne
• Frequency range: 10 - 120 kHz (min.)
• Display accuracy: +/- 0.15 kHz
• Bandwidth: 8 kHz (+/- 4 kHz), -6 dB
• Battery: 1 x IEC 6LF22 (9V)
• Quiescent current: 16 mA typ.
• Size: 113 x 71 x 63 mm including knobs
• Weight: 220 g. including battery
• Outputs: 2 x 3.5 mm jacks for headphones and tape recorder.
• Single handed operation

Price
Pettersson D100: $349.00 USD
Shipping charge will be calculated during checkout.