Hello Bob, Thanks for the measurements! Was this with the Alpha’s auxiliary fan on or off? You will find this fan and its belonging switch on the amplifiers back on the right side where the power supply transformer sits.
73, Stefan DL1IAO, SA3CWW/SM9A -- Stefan v. Baltz [email protected] http://www.dl1iao.com > Am 03.06.2018 um 20:33 schrieb Bob Rennard via Elecraft > <[email protected]>: > > My measurements were taken with a microphone about 2 feet from the front > panels of the components. I wondered if W2PA’s alpha 89 was as quiet as he > reported, so I thought I’d report on what I found - > > > > Ham shack in a finished (insulated drywall) room in a metal shed with > equipment and HVAC off - 24 dBa > > Above with Mitsubishi HVAC on - 29 dBa > > HVAC was then turned off for the remainder of these measurements > > KPA1500 PS fans on, RF deck fans off (step 0) - 36 dBa > > KPA1500 PS fans on, RF deck fans at step 1 - 40 dBa > > KPA1500 PS fans on, RF deck fans at step 2 - 44 dBa > > KPA1500 PS fans on, RF deck fans at step 3 - 50 dBa > > KPA1500 PS fans on, RF deck fans at step 4 - 57 dBa > > KPA1500 PS fans on, RF deck fans at step 5 - 59 dBa > > > alpha 87a (everything else off) - 50 dBa - the fans run at a fixed speed when > mains power is applied > > > My experience for S&P CW during WPX is that the KPA1500 PA temp rose to about > 64C so that the deck fans were at Step 2. During a recent RTTY contest, the > deck rose above 70C and the fans were running at Step 3 pushing a lot of warm > air out of the vent holes above the heat sink. > > > 73 & YMMV, > > > Bob Rennard = N7WY > ______________________________________________________________ > 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]
