Sandgrounder
Well-known member
I recently picked up a "Discovery Channel Ultrasonic Detector" from Argos for £7.49, and I think it may be of interest to a number of people, particularly for handing out to groups for guided walks and the like.
The same device is available from Amazon and other retailers, and I see that a couple of bat groups around the UK have been talking about it.
Here's the link to the Argos web site: http://www.argos.co.uk/static/Product/partNumber/1095973.htm
The device is a basic heterodyne detector, with a stated range of 20kHz to 120kHz. The build is that of a cheap plasticky toy, looking more rugged than I imagine it is. There are two knobs: power/volume and frequency. No earphone socket.
The documentation contains a brief description of what sound and therefore ultrasound is, and suggests a number of ultrasound sources to be found in the average household - fizzy drinks, pins dropping, air leaking from balloons etc. Disappointingly, it does not explain how a heterodyne detector works. I know this would be beyond some of the "8+" target demographic, but knowing what you're doing is fun.
I took the device down to a local lake to detect some bats. My experience with bat detectors is limited: one guided walk where assorted heterodynes were handed out to the public, led by a nature reserve ranger who is not a bat specialist. The short version of this review is that we would have done just as well with these toy bat detectors as we did with our Magentas that day.
Using the toy detector, I was able to identify at last three different echolocation calls. Noctules at around 25 kHz, the rat-a-tat-tat of Daubenton's at around 45 kHz, and a wet slapping sound that I assume must be some kind of Pipistrelle also around 45kHz. I could also see what I take to be Noctules dive-bombing the lake and Daubenton's skimming the surface.
Not bad for a first attempt. I didn't get anything at the higher frequencies, but didn't particularly expect to either. Plenty of other types of bats have been recorded locally and with experience and greater confidence in my ability to assign the calls of the most common species I would hope to be able to identify them too, if present.
In summary:
Pros
The small, nonlinear frequency knob doesn't inspire confidence in its precision. When I say "about 40kHz" I feel that's with a certainty of +/- 5 kHz, and it's not easy to read in the dark. So I don't think this device is good enough for species identification beyond the very distinctive ones, or at least only by somebody with a lot of experience, who would already have better equipment.
However, for certain people this device is a good buy. For events like the bat walk I attended a couple of years ago, this device would have been as useful as the mixture of Magenta Bat-3 and Bat-4 devices that was handed out, and we could have had a better people:detectors ratio.
I'm happy with my purchase: I'm on a limited budget and am not about to spend £80+ on an entry-level 'proper' bat detector. But £7.49 pays for itself quickly by encouraging me to lurk in the beer garden rather than buying my round.
It also strikes me as the sort of thing it would be fun to have in scout groups or groups doing Duke of Edinburgh's award hikes and things like that.
The same device is available from Amazon and other retailers, and I see that a couple of bat groups around the UK have been talking about it.
Here's the link to the Argos web site: http://www.argos.co.uk/static/Product/partNumber/1095973.htm
The device is a basic heterodyne detector, with a stated range of 20kHz to 120kHz. The build is that of a cheap plasticky toy, looking more rugged than I imagine it is. There are two knobs: power/volume and frequency. No earphone socket.
The documentation contains a brief description of what sound and therefore ultrasound is, and suggests a number of ultrasound sources to be found in the average household - fizzy drinks, pins dropping, air leaking from balloons etc. Disappointingly, it does not explain how a heterodyne detector works. I know this would be beyond some of the "8+" target demographic, but knowing what you're doing is fun.
I took the device down to a local lake to detect some bats. My experience with bat detectors is limited: one guided walk where assorted heterodynes were handed out to the public, led by a nature reserve ranger who is not a bat specialist. The short version of this review is that we would have done just as well with these toy bat detectors as we did with our Magentas that day.
Using the toy detector, I was able to identify at last three different echolocation calls. Noctules at around 25 kHz, the rat-a-tat-tat of Daubenton's at around 45 kHz, and a wet slapping sound that I assume must be some kind of Pipistrelle also around 45kHz. I could also see what I take to be Noctules dive-bombing the lake and Daubenton's skimming the surface.
Not bad for a first attempt. I didn't get anything at the higher frequencies, but didn't particularly expect to either. Plenty of other types of bats have been recorded locally and with experience and greater confidence in my ability to assign the calls of the most common species I would hope to be able to identify them too, if present.
In summary:
Pros
- It detects bats.
- The price. Look at the price.
- The frequency knob is small, and nonlinear so there's a big gap between 20 and 40 kHz and the rest are close together.
- The device is designed for two-handed operation but you'll need a third hand for a torch to read the frequency dial.
- I would have liked an earphone socket.
- There's a constant background hiss even at fairly low gain. I don't know how this compares to other detectors.
The small, nonlinear frequency knob doesn't inspire confidence in its precision. When I say "about 40kHz" I feel that's with a certainty of +/- 5 kHz, and it's not easy to read in the dark. So I don't think this device is good enough for species identification beyond the very distinctive ones, or at least only by somebody with a lot of experience, who would already have better equipment.
However, for certain people this device is a good buy. For events like the bat walk I attended a couple of years ago, this device would have been as useful as the mixture of Magenta Bat-3 and Bat-4 devices that was handed out, and we could have had a better people:detectors ratio.
I'm happy with my purchase: I'm on a limited budget and am not about to spend £80+ on an entry-level 'proper' bat detector. But £7.49 pays for itself quickly by encouraging me to lurk in the beer garden rather than buying my round.
It also strikes me as the sort of thing it would be fun to have in scout groups or groups doing Duke of Edinburgh's award hikes and things like that.
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