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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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4th Nov 2019, 7:54 pm | #1 |
Triode
Join Date: Mar 2011
Location: Bristol, UK.
Posts: 44
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Bat detectors again
Hi all,
Digging around for info on this subject, I note an old post here: https://www.vintage-radio.net/forum/...d.php?t=102454 and wondered if anyone has anything to add regarding ultrasonic mics or useful circuits for heterodyne detectors? I came across a Knowles MEMS mic SPU1410LR5H-QB which is described in their application note 17: https://www.digikey.co.uk/en/pdf/k/k...ms-microphones as having a useful if peaky response to 100kHz. Just wondered if anyone has used this successfully as it looks a little tricky to solder, and I am unsure how it would interface with the NE612 mixer design referred to in my first link. In the meantime I await some Panasonic electret mic WM-61 |
4th Nov 2019, 8:14 pm | #2 |
Nonode
Join Date: Jun 2016
Location: Bognor Regis, West Sussex, UK.
Posts: 2,288
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Re: Bat detectors again
I built a Magenta MkII bat detector some years ago and it is very effective, indeed I still use it. This a hetrodyne type using an electret capsule.
https://www.magenta2000.co.uk/acatal...ctor_Mk_2.html I have detected Pipistrelle, Daubenton's and Lesser horseshoe. Peter |
5th Nov 2019, 9:13 am | #3 |
Nonode
Join Date: Jun 2016
Location: Bognor Regis, West Sussex, UK.
Posts: 2,288
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Re: Bat detectors again
I have just read the thread linked in post #1 and have discovered that the Lesser Horseshoe transmits at 110kHz which makes my Magenta II more impressive than I thought.
We saw the Lesser Horseshoes coming out of a house roof in a village beside the Mon and Brec canal in Wales. I had the detector with me and was suprised to find I could not detect anything on its usual setting and had to retune. It was dark so I did not see what the frequency was at the time. The reason I know they were Lesser Horseshoe is that there was a notice posted telling us what they were. Peter |
5th Nov 2019, 11:02 am | #4 |
Nonode
Join Date: Jan 2004
Location: 1966-1976 Coverack in Cornwall and Helston Cornwall. 1976-present Bristol/Bath area.
Posts: 2,965
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Re: Bat detectors again
I also built the Magenta mk2 kit and it worked very well. It was most sensitive around the 30Khz -50Khz range but dropped off considerably either side of this. I think it is down to the type of condenser microphone they used.
Spent many late summer evenings watching and listening to the bats around the 40Khz mark.
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Simon BVWS member |
5th Nov 2019, 12:33 pm | #5 | |
Heptode
Join Date: May 2008
Location: Selby, North Yorkshire, UK.
Posts: 949
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Re: Bat detectors again
Quote:
SO theres a winter project - find those mics from among my stash, and upgrade my bat detector!
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5th Nov 2019, 1:59 pm | #6 | ||
Triode
Join Date: Mar 2011
Location: Bristol, UK.
Posts: 44
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Re: Bat detectors again
Quote:
The Knowles MEMS mics sound interesting.... Keith |
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