[HomeBrew] Pixie II RIT Question

[Eugene Crist]

I recently bought and assembled a Pixie II from HSC (the $10 kit) so I can
test and modify it in an attempt to better understand what's going on in the
other transceiver's I've built. I assembled the rig and everything works as
it should. I want to build another one from scratch so I laid out a new
board in Express PCB and I'm planning on etching it in the next few
days. The only improvement I've incorporated in the board is the RIT circuit
from the original instructions I got with the HSC kit. According to the
instructions, you connect a 60-70 pF variable cap on the grounded side of
the crystal, and you install a switch in parallel with the cap. So when the
switch is open, the cap is in series with the crystal and I'm assuming it'll
raise the frequency about 600 Hz. When the swich is closed the crystal is
grounded through the switch and returned to it's fundamental frequency.

Now for my question. I saw on the WE6W website what looked like a QRPL post
(http://www.qsl.net/we6w/projects/pix_tips2.txt) where Ed Loranger stated
that two capacitors should be installed on the ground side of the crystal; a
switched .001 uF cap in parallel with a 60 pF cap. He said when the switch
is open and only the 60 pF cap is in series with the crystal, it'll pull the
crystal about 600 Hz giving the proper offset, and when the switch is closed
the .001 cap will give a good ground and return the crystal to it's
fundamental frequency. The part that I'm confused about is why would you
want to switch in a .001 uF cap in series with the crystal (and in parallel
with the 60 pF cap) instead of just ommitting the .001 cap and grounding it
directly through the switch as stated in the HSC instructions? Any info
would be appreciated.

Thanks, Gene (KB3ONA)