[Elecraft] KSB2 Mod's

[Donald Nesbitt]

Hey Sid - HNY -

> I recently completed K2#3863 & having a ball on CW.  Now I have received .
. . .

No wonder I don't hear you on 20 ssb anymore!

> A. "Crystal Filter Bandwidth Mod":  I have the mod cap's from Elecraft . .
. .

Personally, I like the 2.5 kHz mod and have done it to one of my KSB2
boards.  I have two (2) KSB2 boards but only one K2 - got the second KSB2
just to experiment with.  With the 2.5 kHz mod my actual measured bandwidth
at about 6db down turned out to be more on the order 2.0 kHz.  Much better
than the "stock" build that turned out to be a very skinny 1.75 kHz at 6db
down! (even with the 14 xtal replacement set - not to worry, you don't need
the new xtals).   I'm just pretty much a "dxer" (336 confirmed)  and find
that the actual bandwidth that I got is quite good for dxing and ok for
casual contacts.  Others will have various opinions about the 2.2, etc -
BUT - it is a heck of a lot easier to do the mod without the xtals installed
than it is to go back later and do it!!  And yes, I've done it both ways -
yuk!

> B. "Improved 2nd. Xtal Filter Flatness Mod";  This mod was as built, I . .
.

Yep, part of > #3000 and very worthy!

> C. "KSB2 Increased Gain Mod":  Do I install now?  I will have to purchase
. . . .

I'm not familiar with the Heil Traveler mic so someone who is would be a
better judge of this.  Personally, I'd build initially without this mod to
see if you really needed to do it.  I've done it to one of my ssb boards -
it does work just fine - but it is a little hassle and you can always do it
later without too much fuss if you find that you really need to do it.  On
the other hand, I have increased R14 on the KSB2 board (originally a 1 k) to
3.3 k to give a bit more gain from some marginal mics (Heil HC-4 and HC-5)
with moderate (not great, just moderate) success.  There has been some
discussion on this "mod" on the reflector and as much as 5.6 k has been
suggested from time to time.  Given various technical concerns, (rf,
rolloff, etc, etc) I think that 5.6 k may be a bit much.  I'd suggest
sticking with the original 1 k and maybe trying a bit more later if you
wanted to experiment without going to the full-blown transistor mod.  R14 is
very easy to change.

> KI6WX & N0SS that I don't want to create the wheel . . . .

Agreed!  Two great guys with technical prowess (and apparently quite good
labs) and a flare for communicating same!  '73 es have fun  --don n4hh
K2/100 #2028