[RFI] 40khz Oscillator for ultrasonic dish testing

[Gedas]

If you want to have some fun and generate lots of high intensity 
ultrasonic signals pass some high pressure air through a small orifice 
or over a sharp edge.

Gedas, W8BYA EN70JT

Gallery at http://w8bya.com (under repair)
Light travels faster than sound....
This is why some people appear bright until you hear them speak.

On 5/31/2021 8:59 PM, n0tt1 at juno.com wrote:
> 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 at 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 at 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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