Hi Guys:
I had some time over the holiday to finish off my second
scratch-built rig. I am very thankful that I got the work done on these
projects before I read Pete's "Don't Build It" diatribe. That
would have been very demoralizing. :-)
Scratch build #2 (called Peppermint III) is still fundamentally
BITX although I've made changes this time around. I've
switched to ADE-1 mixers with LO ports driven by adjustable gain buffers
(ala N6QW LBS). I've noticed that performance can be improved a lot if
you can buffer/tweak the LO levels of the VFO and BFO (particularly carrier
suppression on TX). I did W7ZOI TIAs in the IF chain. I've also
taken the shielding/layout of the finals more seriously and have been able to
dial up the power a lot (I did the KB1GMX thing with cutting off the drain pin
on the IRF510 and using the tab). The software is also greatly improved
and now supports LSB/USB modes as well as software-driven PTT control for
RTTY/FT8 and the hooks for my poor man's panadaptor. I've been working
lots of stations on QRO.
Total build time was about three months (half the time of #1)
and the layout came out much smaller than before. I made a trip over to
Williams/Sonoma after Christmas and picked up the 2018 edition of the
Peppermint Bark candy tin on discount and I think I can make it all fit.
More to follow ...
Happy New Year and 73s,
Bruce KC1FSZ