When running RTTY with the KPA500 I no longer have, I noticed that, with
a minimum fan speed greater than zero, the temp tended to fall lower
during RX periods than when the min speed was zero. During the
subsequent TX period, having started from a lower temp, it would not
rise as high, keeping the fan speed one step lower by the end of the TX
period. I assume this was because there is significant thermal
"inertia" in the amplifier but thermodynamics was never my best
subject. RTTY operation tends to have a regular-ish pattern of on-off,
I never noticed the fan going to high on CW. I suppose the FT modes
would present an even more regular pattern.
All anecdotal Andy, I didn't bother to take any data.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
On 9/29/2019 7:38 PM, Andy Durbin wrote:
The KPA500 offers a minimum fan speed setting which is settable by menu or
serial command. Some posters have advocated setting a minimum fan speed higher
than zero, presumably thinking it offers some advantage in thermal management.
Does anyone have any hard data that shows that the KPA500 runs cooler, or with
lower peak fan speed, when minimum fan speed is set above zero.
Running a rigorous test may not be easy since it would seem to require the same
ambient temperature, same finals starting temperature, same TX periods, and
same antenna system load.
I'm curious because, before CQ-WW-RTTY I configured my KPA500 to set min fan
speed to 1 at start of TX and reset min speed to zero 30 seconds after stop of
TX. Of course the fans ran faster than min speed during TX but I don't have
any feel for whether the higher speeds were any more protracted than before the
min speed change.
Please share you experience of using min fan speed greater than zero, and any
data if you have it.
73,
Andy, k3wyc
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