[Elecraft] KPA 100 Question

[Ron D'Eau Claire]

Lee, K0WA wrote:

I was operating 40 - CW  the other day with the K2/100 using the KAT100 into
a dipole.  After a few minutes, the fan roared into life.  I've never had
that happen before in all the years I've operated the rig.  Strange.  After
I turned it over to the other station, a few minutes it quit.  The antenna
was matched through the KAT100.  Now, I know it is operating OK...I read the
manual.  But, I wondered why the thing went on cause I've never heard it go
on before.  After the QSO, I checked the tpa and found it was set for 24 c
while the room was at 17 c.  Could that have been an issue?  Maybe I am just
being and old clucking hen, but I want to understand what is going on there?
I know it goes on at 40 C.  I have the fan set to FAN HI.  Anyone can
enlighten me?

--------------------------------------

The fan goes on and off automatically, based on the internal temperature, to
keep the finals within their rated temperature. The more power you're
running, the more likely it'll pop on after a period of transmitting. It
runs for a bit after you stop sending until the temperature settles down
again. 

The temperature shown in the menu should have equaled your room temperature
unless you checked it after transmitting. See "Temperature Calibration (CAL
tPA)" in your manual to set it. That may delay its onset, but it should come
on when the finals heat up enough. 

As for being an "old clucking hen", I'm convinced fans are Satan's revenge
upon Hams for enjoying radio too much! To me they are like fingernails being
drawn across a slate "blackboard", but perhaps only us OT's remember those
as well, Hi! On the other hand, the fan does eliminate the need for a really
huge heat sink. Every time I see an old "boatanchor" rig that ran only 1/2
the power of my K2/100 and which would occupy the space of a dozen K2's (and
weigh as much as a hundred of them) I decide the need for a fan is probably
a rather decent trade-off. 

Ron AC7AC