[Ham-Mac] Tip of the Day: Input Drive Level for Digital Signals

[Dick Kriss]

Old dogs can learn new tricks.  I have been having a sometimes issue I did
not understand with cocoaModem 2 and the SignaLink USB.  After a few minutes
of good decoding in RTTY or PSK, the copy would become garbled and I was
having to quit and restart cocoaModem and toggle the SL USB's On/Off switch
to get good copy again.

It finally dawned on me that I may be overdriving the A-to-D converter so I
reduced the output from the rig and the Rx control on the SL USB and I have
not seen the problem again. The decoding is great.

The audio output level from the Kenwood TS-570S(G) can be adjusted by Menu
item #34 with a range of 0 to 9.  Mine was set to 7 so I reduced it to 4 and
the sometimes garbled text is history.  I recall the 7 setting was required
when I had the older SL-1+ and I failed to re-adjust the setting when I
changed to the SL USB.

Too much input is not a good thing so double check your receive audio
levels.

73 Dick AA5VU