I'm in the process of trying to bring an early K2 (serial#653) kicking and
into the 21st Century, I'll also point out that I'm not the original builder
For a while I've not been overly convinced about the sensitivity and dynamic
range of this particular example, it hasn't helped matters that along the
in my investigations I found numerous build errors.
Today my attention was drawn to the Noise Blanker option. I downloaded
the manual and noticed there were some major differences between my
example and that referenced in the manual. I have looked through the
Elecraft website and found the archived manual for the main build but I
can't find an archived manual for this particular example of Noise Blanker.
I'm lucky in that I have a friend very local to me who is in the process of
building a K2 and so this morning I had the opertuinity to try his more
noise blanker board in my K2. WHAT A DIFFERENCE!!!!
I would guestimate that there was a 25-30dB increase in performance when his
noise blanker was installed.
The biggest visual differences between the two boards are:
My older example has variable capacitors for C3 and C5.
Pins 5 and 6 of U3 are shorted together
L1 and L2 are grey torroids, L1 having 13winding and
L2 having 14 windings
L3 is marked with brownish orangey paint and has 15 windings.
I'm hoping someone maybe able to point me to an archived manual
for this earlier version of the noise blanker so I can assertain if it is
reworkable or whether a newer revision should be purchased.