[time-nuts] FRS-C TTL / sine outboard filter question

Leigh L. Klotz, Jr. WA5ZNU Leigh at WA5ZNU.org
Wed Jun 23 16:19:32 EDT 2010


Mike S wrote:

> It sounds like you made the changes to the A4 oscillator board, but not
> the ones to the A3 power supply board (several inductors, resistors
> and caps). I found that using a 1 uF for C16, instead of the
> documented 0.1 uF, gives a better signal.
> See the top of page A-15 in the manual.

Thank you.  This is just what I needed to hear.  I had clearly overlooked
that page.

I've made an attempt at reading page A-15 for the 10 MHz sine option, and
consulted the schematic and parts list on the succeeding pages.  I still
don't have legible values for L1, L2, and R16.

If you have these values we can document the rest of this process in one
place.

10 MHz sine                 TTL
L1   ?.? uH                 L1 OMIT
L2   1? uH                  Replace with R23 130 OHM 1 WATT
R16  ?10 OHM NOM            100 OHM NOM
R17  1.0K                   274 OHM NOM 1/4W
R18  1.0K                   OMIT
C8   47pF NOM               JUMPER
C9   6800pf NOM             0.47 uF NOM
C16  0.1uF [1uF: see above] JUMPER
C17  240pF NOM NP0          OMIT
                            INSTALL JUMPER A-0

Leigh.







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