[Elecraft] KPA500 thermal clicks

[ANDY DURBIN]

I placed my Android phone on top of my KPA500 and made a recording while making a few cycles of FT8 TX/RX.  The audio files can be found here:

https://www.dropbox.com/sh/amfy3dz8pgl083n/AAAKi2GYripXyIDjiLpJ2hDwa?dl=0


One file is the raw recording.  The second has been processed in Audacity to amplify to 0 dB peak.  The file starts before the first TX. Next the hum of the transformer can be heard with FT8 modulation in the background from TX moni.   As the recording progresses the changes in fan speed can be heard.   The click are always well above the fan noise.

I used this recording to perform some spectral analysis of the clicks.  I took one sample at the click and another sample of the noise just before the click.  I then subtracted the noise from the click and I think I have a reasonable click signature to use as a baseline for evaluating any mechanical changes I make in an attempt to reduce the clicks.

Crank it up and enjoy, especially if you think it's normal.

73,
Andy k3wyc