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G8MNY  > TECH     18.12.17 11:37l 43 Lines 1640 Bytes #999 (0) @ WW
BID : 2697_GB7CIP
Read: GUEST
Subj: AF Standing Waves
Path: IW8PGT<IZ3LSV<IW0QNL<JH4XSY<F1OYP<AB0AF<NS2B<KE0GB<GB7YEW<GB7CIP
Sent: 171218/0952Z @:GB7CIP.#32.GBR.EURO #:2697 [Caterham Surrey GBR] $:2697_GB
From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@WW

By G8MNY                               (New Apr 17)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

While laying around for a week in Hospital & a noisy night time drug pump Alarm
on the adjacent bed, I found myself playing sound games when I could not sleep.

   ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
   ³                   Bed                  ³
   ³Bed±±±±            ±±±           ±±±±Bed³
   ³                   ±±±                  ³________
   ³
   ³                                        Corridor
   ³                                         ________
   ³  ±±±              ±±±             ±±±  ³
   ³  ±±± []           ±±±             ±±±  ³
   ³  Bed Alarm        Me              Bed  ³
   ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ

I was in the middle of a 6 bed ward. The alarm was a loud pure note (1.5kHz?)
& I found with my head on one side & moving just a few mm, I could get a VERY
deep nulls (60dB) in the tone from the reflections bouncing up & down the room.

   |  _    _    _    _    _    _    _    _  |
   | / \  / \  / \  / \  / \  / \  / \  / \ |
   |/   \/   \/   \/   \/   \/   \/   \/   \|
   |       ³            ³                   |
 Wall    Alarm        Nulls               Wall

Then when the nurse approached from the corridor, I could detect this with the
standing wave reflections were being disturbed. This gave a loud multiple
Doppler ping sounds for each node the nurse went through.


All quiet interesting when you have nothing else to do in Hospital at night!


Why don't U send an interesting bul?

73 De John, G8MNY @ GB7CIP


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