Just rubbing your fingers together works very well. And yes, car
keys, walking in grass, bees, etc all generate ultrasonics.
Charlie, N0TT
On Tue, 1 Jun 2021 00:22:45 +0000 (UTC) AA5CT via RFI
<rfi@contesting.com> writes:
>
> If memory serves me correct, playing around with an ultrasonic
> receiver years ago I noticed that car keys gave off quite a bit of
> 'noise' (ringing and jangling) when shaken ... perhaps another
> easy source to verify ultrasonic 'dish' operation in the field?
>
> de AA5CT Jim
>
>
>
> On Monday, May 31, 2021, 4:03:01 PM GMT-5, Charles Plunk
> <af4o@twc.com> wrote:
>
>
> Sit down and whipped up a 40khz oscillator. If nothing else gives me
>
> confidence the dish is working. The dish is pretty much spot on and
> if
> go by max signal its very accurate at 30'. At some point need to
> make
> taps on the dish circuit for measuring max signal to make sure the
> detector is in the right position in front of the dish. I'm guessing
> it
> is close.
>
> https://www.facebook.com/media/set/?set=a.107413994889511&type=3
>
> Chuck
> W4NBO
>
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