[Elecraft] K3 Duty cycle

[Gary Hvizdak]

At 0114 EDT on Sat 17 May 2008 Jim Miller (KG0KP) wrote ...

What is considered the practical duty cycle of the K3/100 ...?

--

Jim,

Page 9 of the K3 manual states: Duty Cycle CW and SSB modes, 100% 10-min.
100W key-down at 25 C [77 F] ambient
:
:
I assume the K3 owner's manual is more up to date than the following FAQ
entry on Elecraft's website
:
:
Q: Does the KPA3 have plenty of power to allow for 100-W full duty cycle
operation in all modes?

A: We may limit power level or maximum TX time for 100% duty-cycle modes
(AM/FM/FSK).  I can't say for certain, because we're still doing extended
transmit tests.  We used two fairly large, standard-size fans so they'd run
at slow speed in most operating situations.  But fans in this size are
readily available with higher CFM ratings, so we could offer an extended-
duty-cycle upgrade if that were warranted.  This would only increase the
depth of the fans; you wouldn't have to add fans to the top of the cabinet

The fans have 4 speeds, are temperature controlled, and they turn off when
not needed.  They're large and quiet.

In fact the entire fan panel is an upgradeable module -- we wanted to make
sure the K3 could adapt to specialized requirements.

So far our feedback from RTTY contesters is that they were able to operate a
whole contest without getting the K3's heatsink too hot.  The fans rarely
went to full speed.