The Magenta ‘Bat5’ Digital Quartz Bat Detector

1 The Magenta bat5 Digital Quartz Bat DetectorMagenta Electronics Ltd 135 Hunter Street Burton on Trent Staffs DE14 2 STTel. 01283 565435 Fax. 01283 546932 e-mail: Magenta bat5 is anentirely new Superheterodyne Bat Detector with an illuminated easy to read lcd frequencydisplay. It has been developed from our years of experience, and advice from users of Magenta :Price the Magenta bat5 Bat detector1 Introduction2 How it Works!3 Controls4 Display5 Batteries6 Checking7 In the field 8 Technical SpecificationIntroductionBats use inaudible ultrasonic sounds like a sophisticated radarsystem to avoid obstacles and locate bat5 Detector takes the inaudible high frequency ultrasound andconverts it to frequencies between 100Hz and 12kHz which are in therange of human Detector can be tuned to receive a range of frequencies from 10to 130 kHz.

2 The sounds are heard via a built in waterproof loudspeak-er, and there is a socket to connect standard stereo walkman type headphones. A separate constant low level output is provided forconnection to a tape recorder or PC sound it WorksThe Detector uses the Heterodyne principle. Ultrasound is picked up,amplified, and mixed in a special way with another signal generatedin the bat Detector . The mixer produces the audible differencefrequency between the two. In a typical situation the bat will besending ultrasound at 45kHz, the bat Detector signal will be set to43kHz and the audible output will be the difference between the two- which is are two rotary controls.

3 A combined volume on/off switch, anda large calibrated frequency control which adjusts the signal to bemixed with the ultrasound from the small push button switch turns on a bright white LED torch large LCD Display shows the frequency with Quartz accuracy towithin 100Hz. A low current backlight illuminates the display with asoft even light for night AAA alkaline or rechargeable batteries are used. The Bat5works equally well with both types. Alkaline give very long life, whilstmodern rechargeable cells - especially NiMH are an environmentallyfriendly :Make sure the Detector is switched OFF when changingthe are many common sources of ultrasound - jangling keys,rustling newspapers, rubbing two fingers together, and droppingpaper clips onto a hard surface all produce interesting and differentresponses.

4 Computer fans also produce steady ultrasonic of these sources can be used to check that the Detector isworking. Start with the volume half way, and set the frequency controlto heterodyne principle is demonstrated very well if continuoussource such as a computer fan is available. As the frequency controlis rotated, the pitch of the Detector output will change and fall to zerowhen the frequency of the fan noise and the local signal are the Frequency control in either direction will result in thepitch rising, as the difference between the two signals the FieldWhen looking for bats, set the frequency to 45kHz.

5 Many differentbats echolocate at around this frequency. When looking for a partic-ular species set the control to the appropriate frequency and scan the area by pointing the Detector in different directions. Ultrasound isvery directional and the microphone is much more sensitive to headon signals than to signals from either side. It is often possible tolocate a bat by pointing the Detector to the strongest ultrasound longbefore it can be bats are detected, the frequency control can be fine tuned toget the best signal. If there are two relatively close frequency settingsthat give similar signals, always chose the lower one*.

6 The Detector only receives ultrasound, it does not transmit anythingthat will disturb the bats. The only output is the audible signal fromthe loudspeaker - which (presumably) is of no interest to the batseven if they could hear it.*Heterodyne detectors produce the difference between the bat fre-quency and the local signal. If the bat frequency is below the localsignal frequency, a fall in the bat frequency will result in a rise in thepitch of the audible signal - because the difference will be is an inversion of the frequency spectrum .If the Bat frequency is above the local signal, a fall in the bat fre-quency will reduce the difference and so produce a fall in the audiblesignal - so the frequency spectrum is the right way SpecificationType: HeterodyneFrequency Range: 10kHz - 130kHzBandwidth: +/- 9kHzOutput power: wattsHeadphone socket: StereoTape Socket: stereo jackTape Output: 100mV typicalLED torch White 5mm : 4 x AAAS peaker: Waterproof low profile mylarMicrophone: Wide band Magenta bat5 Detector was designed in Denmark and is built inEngland by.

7 Magenta Electronics Ltd135 Hunter Street Burton on TrentStaffs UK DE14 2 STTel. 44 (0)1283 565435 Fax. 44 (0)1283 bat5 Special Technical Details.