The ticking sound is clearly the resonant aluminum heat sink fins. The mechanical shrinking or expanding is abrupt and resonates the fins much like a tuning fork. My take on it...
Chuck Amateur Radio, KE9UW _____ From: elecraft-boun...@mailman.qth.net [elecraft-boun...@mailman.qth.net] on behalf of Martin Sole [hs0...@gmail.com] Sent: Wednesday, July 18, 2018 8:37 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KPA500 thermal clicks I think it sounds "orrible!". I'm quite used to the low rumble of the blower in my Alpha 77D but that ticking would be like Chinese water torture to me. Listening to an individual tick it does seem to have a ring to it. Okay the recording was perhaps not the most acoustically perfect but it certainly does sound as if the ring is from the source and not any sort of artifact. If it is from the source then I think you can probably find a way to damp it. First trick will be to identify the specific source. I had read other comments about a ticking, always imagined it to be minimal and essentially unobtrusive but if what you have recorded is anything like how it sounds sat in front of it then definitely it does sound pretty bad to me and not just in amplitude but also in its timbre, pitch, and repetition rate. Martin, HS0ZED On 19/07/2018 06:25, ANDY DURBIN wrote: > 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 > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to hs0...@gmail.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to c-haw...@illinois.edu ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
