[Elecraft] K3 SHUTDOWN.

[Fred Jensen]

I ran RTTY on my K2/100 for several years at 100W.  I did the same thing 
as Mark.  An old computer muffin fan with a little screen over the top 
velcro-ed to a small patch on the KPA100 heat sink ... right rear area, 
if I remember correctly.  It blew down on the heatsink, made no noise 
that I could hear at 12V **, and the heatsink stayed cool to the touch @ 
100W while CQ'ing.

RTTY, digital modes, AM, FM, and for that matter CW when the key is 
down, is a CCS application just like a broadcast transmitter.  We count 
on CW to have enough key-up time to reduce that average power.  If you 
S&P on RTTY, you shouldn't have any problems, I didn't on the K2/100, 
and I don't on the K3/KPA500.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org

** Computer fans sometimes behave strangely in the presence of RF. 
Mine, on 15m, with the beam headed SW back over the shack, would slow 
and sometimes stop while the carrier was present when I was driving an 
amp to maybe 400W.  And all the sprinkler valves under my 160 antenna 
tried to follow 30WPM CW on 160m at about 900W. That is hard on the 
plumbing. :-)

On 9/29/2012 2:27 PM, Mark n2qt wrote:
> I run a 5inch sized 24V fan powered from 12 volts or so during
> RTTY contests.  I watch the PA temperature, but don't normally
> see it going above the upper 40's no matter how hard I push it
> at the 100 watt level.