[Elecraft] Option and building

[k6se@juno.com]

Jim, KA7MQB wrote:

"I'm budgeting for a K2 and need to know is it best to build the options
during the initial build or is it OK to add them on later.  Does one
waste time in adding them on later?"
----------
Build and test the K2 first., but while building it install the "option
jumpers" keeping in mind that they will be removed when you install the
options.  Option jumpers are merely jumper wires soldered onto the K2 PC
board(s) so the at the K2 will work without the options.  I suggest that
you make the option jumpers slightly long so that they may be easily
clipped and de-soldered later when you install the various options.
==========

"Finally, I operate 95% CW at 5 watts (now using the FT-817...BTW  great
rig.)  What are the most important options to enhance the K2?"
----------
Because you operate mostly CW, the KAF2 audio filter (and RT clock)
option is essential in my opinion.  If you anticipate noise, then get the
noise blanker kit.  If you plan to operate on topband, you need the
160-meter kit.  The internal battery kit might be useful for portable
operation if you don't want to lug along a large 12VDC storage battery. 
If you plan to control various K2 functions via computer or want to
interface your favorite logging computer program with the K2, get the I/O
kit (unless you eventually plan to buy the 100-watt kit which includes
the I/O option).  If you plan any SSB operation at all, you'll need the
KSB2 kit.  If you plan to use antennas which are not coax-fed (or have a
high SWR), then you'll need the antenna tuner kit.

There is a "mod" described in the K2 manual on how to wind the final PA
binocular toroid for more efficiency at 5 watts.  It'll save a few
milliamps at that power level and might be a consideration for you if you
plan to do much battery-operated portable operation at the 5-watt level. 
Otherwise, I recommend that you wire that toroid normally (for best
efficiency at 10 watts).  You can still operate anywhere from about 200
mw to over 10 watts depending on where you set the K2's front panel POWER
control.

Some of the option kits add a slight amount of current drain to your
power supply.  I have the SSB, AF filter, noise blanker, and 160-meter
options install in my K2.  I draw about 250 ma on receive and, with the
front panel POWER control set at 5.0 watts (and the binocular toriod
wound normally), about 1.6 amps on transmit when using a 13.8-volt
regulated supply with my K2.

73, de Earl, K6SE
66 countries and counting with K2 #2622