Re: Listening to TC?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <teslalist-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Matt,

On 20 Jun 2003, at 7:33, Tesla list wrote:

 > Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
<Mddeming-at-aol-dot-com>
 >
 > Hi All,
 >
 >         We all know that spark gaps and streamers make some pretty awesome
 > sounds, but what about "ultrasounds"? These would be sounds from 15KHz on
 > up to the resonant frequency of the coil. This question is prompted by the
 > following: Last night, a bat got into the instrument/people section of the
 > lab. (The TC section is inside a grounded 10ftx10ftx8ft cage). With the
 > coil running, the bat ran into the wall the way a bird or insect will beat
 > against a window trying to get out. I turned off the coil and it
 > immediately turned around and flew back out the door which was only open
 > about 5 inches.  Makes me think maybe the coil was making sonar-jamming
 > noises. Of course, it could be pure coincidence.

Why should the noise suddenly drop off at the limit of human hearing?
;)

Malcolm