[Elecraft] KPA-1500 Fan Noise - measured (sort of)

[Michael Walker]

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 <rmcgraw at blomand.net>
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 90º 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:Elecraft at 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 rmcgraw at blomand.net
>>
>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at 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 va3mw at portcredit.net
>