When I was a kid, a local department store had some kind of ultrasonic
alarm system that drove me nuts. I used to also be able to hear the 15
kHz sound from TV sweep oscillators.
One of the advantages of growing up is not hearing these any more !
73,
Steve, N2IC
On 02/06/2015 12:14 PM, Mike Waters wrote:
Somebody suggested having a young person listen for a very-high pitched
sound. I think that's a very good idea indeed. Has that been tried yet?
I know a teenage boy that can hear the 'ultrasonic' noise emanating from
most cell phone and tablet screens, and at a considerable distance.
73, Mike
www.w0btu.com
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