Those numbers are pretty impressive for quiet. Certainly quieter than a quiet dishwasher unless you really pushing it.
Mike va3mw On Sat, Jun 2, 2018 at 11:09 PM, Bob McGraw K4TAX <[email protected]> wrote: > Using a Sound Level Meter with A weighted scale, measure the noise at 1 > meter in at least 4 different directions. Preferably done in a "free > field" such that any acoustic reflections are at least 6 meters distant. > I know it is difficult to make measurement outside on a piece of equipment > such as this. But with these measurements one will have some quantitative > data to evaluate. {One side may be noticeably quieter. Thus turning the > amp 90ยบ could make a difference. > > Also, an audio spectrum analysis of the noise would be nice. There may be > certain frequencies related to blade tip speed, or bearing chatter which > can be addressed. > > I know Jim, K9YC will have extensive knowledge about this method of > evaluating "noise" and can offer some solid advice. > > 73 > > Bob, K4TAX > > > On 6/2/2018 6:12 PM, Chris Codella, W2PA wrote: > >> In an attempt to quantify this, I installed OSHA's free NIOSH app, which >> measures noise, onto my iPhone 7 and tried it out. It's not a measurement >> instrument, mind you, so the absolute numbers are highly questionable. But >> the relative numbers are interesting. I held the phone at eye level >> between me and my computer monitor, about 2 feet from the amplifiers. Here >> are the results: >> >> dB measured with NIOSH app, rounded to two significant digits: >> >> 46 - for comparison - an Alpha 89 running as normal >> 48 - KPA1500 at fan level 0 (i.e. PS fans only) >> 51 - fan level 1 (i.e. center fan plus PS fans) >> 57 - fan level 2 (all fans on) >> 64 - fan level 3 (all fans on) >> 67 - fan level 4 (all fans on) >> 76 - fan level 5 (all fans on) >> >> Similar to other comments I've read, I find up through level 2 to be >> okay. At 3 and above I need headphones or, better still, noise cancelling >> ones. My experience thus far is that on SSB in normal conversation at >> 1500W it stays at level 0 with an occasional excursion into level 1 if I'm >> long winded. In the CW WPX test last weekend, strictly in S&P mode, it >> stayed at level 0. Experiments with CQing and on FT-8 are yet to come and >> I'm sure will require higher speeds. >> >> 73, >> Chris, W2PA >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [email protected] >> >> > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
