FWIW - My test using the Alpha 89, was with only the built-in fan on,
not the add-on one in back (which I've never really had to use).
73,
Chris, W2PA
On 6/4/2018 4:43 AM, Stefan von Baltz, DL1IAO wrote:
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
dl1...@contesting.com
http://www.dl1iao.com
Am 03.06.2018 um 20:33 schrieb Bob Rennard via Elecraft
<elecraft@mailman.qth.net>:
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
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