Pettersson D 240x Bat Detector
The Pettersson D 240x bat detector is a high specification dual system Heterodyne and time expansion (X10 or X20) unit. The D 240x isn't for beginners, but for professionals and advanced (but not impoverished) bat trackers. The instructions fill half a dozen pages of A4 of mostly technical talk, and I don't think we really got the most out of trial. Having said that, once we had had a little time using the D 240x we could find little fault. The automatic playback of the Time Expansion gave us a real thrill; listening to the previously silent Pipistrelles as they flitted around our heads.
We found it easy to switch from one system to the other, and back again, in no time. This meant that once we had detected a bat with the Heterodyne detector, we could instantly switch to the Time Expansion system to record and play back the ultrasonic calls of the bats.
Automatic trigger mode
There is also an Automatic trigger mode which allows you to set a certain trigger level for the detector to automatically record the sounds to the memory. This can be useful when there are few bats about, or even if you want to go and make a cup of tea.
There is an output jack which you can plug into a recorder, or some headphones.
I still get frustrated that if you spend £1000+ on a bat detector, it doesn't come with any information as to which species of bat you might be listening to. Some sort of guide to the regional distribution of local bats and the frequencies that they 'broadcast' on. But then I suppose if you are a professional or an 'advanced' bat detector, you would know that information already.
Not quite the top of the range, (the Pettersson D-1000X fills that slot) the D 240x will fulfil pretty much anything but the very most specialist bat detecting roles,
Heterodyne bat detectors are great for beginners and offer immediate identification of bats in the field. You select the ultrasonic frequency range to listen to just like tuning in radio.
Time Expansion detection is a `broadband' method as the entire ultrasonic range audible all the time (in contrast to a Heterodyne detector, which is sensitive only to a limited range of frequencies at each time). Time Expansion detectors first stores a portion of the ultrasonic signal in its digital memory and then replays it at a slower speed, i.e. it is does not transform the calls in real time.
The Pettersson D 240x is available from NHBS for £1099. Click Pettersson D-240X Bat Detector for more details.
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