Thanks for the responses.
Re the "1980s" design, I have an older ARRL handbook c. 2000 that goes
into the design of the OMNI VI in quite a lot of detail, including the
unique LO design. I knew it was good, but I had no idea . . .
Jim: Here's how I do it (a variation of Barry's) on CW: ATTN on. LP
and NR on. 500 Hz filter (N2) in first IF, 250 Hz filter in second IF.
(Going to 500/500 raises noise floor a tad.) Vary the volume as
needed. Of course, with very weak signals, you do hear a bit of noise,
but not much, and in that case you may want to turn off the ATT and
vary the RF gain per Barry. An amazing design.
73,
John, W3ULS
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|