[Elecraft] KPA500 - Advantage of min fan speed?

[Bob McGraw K4TAX]

Personally I think it works great as designed.  Yes there could be changes but I doubt we'd see much, if any difference in performance. 

Hams today in general seem to delight in complaining.  I find many should look in a mirror to identify the source of an issue.  I'm one that believes in keeping things simple. 

Bob, K4TAX


Sent from my iPhone

> On Oct 2, 2019, at 9:12 AM, Bob <WB4SON at gmail.com> wrote:
> 
> Personally, I wish Elecraft offered a slightly different approach, rather
> than a minimum fan speed setting, how about a RX minimum and TX minimum?
> This would allow quiet operation on RX, but would anticipate a higher
> demand for cooling on TX.
> 
> There is quite a bit of thermal mass and overshoot that happens in TX on
> digital modes.  By the time the fan turns on, it tends to be running behind
> the curve trying to catch up.  Starting the fan running as soon as the rig
> goes into TX would help considerably and allow things to go back to quiet
> in RX.
> 
> 73, Bob, WB4SON
> 
> 
>> On Tue, Oct 1, 2019 at 4:58 PM Bob McGraw K4TAX <rmcgraw at blomand.net> wrote:
>> 
>> For SSB voice operation and CW operation I leave the fan speed at
>> NORMAL.   For digital modes, which all have a higher duty cycle, I
>> usually set the fan speed to 1.   I do find the fan speed increments up
>> and down as needed and as driven by the temperature.   When running 400
>> to 500 watts most of the time for digital modes, I occasionally see 60
>> degrees.   The fan speed at 1 does not elevate the room noise at all.
>> In fact, I don't hear it, although I do have sound damping material on
>> the wall immediately behind the equipment.   Usually something in the
>> house or shack is making more noise.
>> 
>> As to if setting the fan speed to 1 for digital modes, it seems to keep
>> the amp temperatures overall a bit lower.  No scientific study conducted.
>> 
>> 73
>> 
>> Bob, K4TAX
>> 
>>> On 10/1/2019 11:51 AM, Andy Durbin wrote:
>>> Thanks to everyone who contributed their experience of operating with
>> min fan speed set above 0.
>>> 
>>> I have some ideas for a test series and I'll share anything I learn from
>> it.
>>> 
>>> Here is a teaser for those interested in KPA500 thermal management.  Did
>> you know that, for a KPA500 that has not transmitted for a long time, the Z
>> bracket is hotter than the heat sink and the heat sink is hotter than the
>> finals.  For that condition the heat flow is from the Z bracket, into the
>> heat sink, and then it heats the finals.  The heat flow reversed during TX
>> as the finals heat up.
>>> 
>>> 73,
>>> Andy, k3wyc
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