IC-746 FAQ
"Hi-Fi SSB" audio is a hot topic within ham radio. Everyone wants the best transmitted
audio they can get, however, not everyone agrees upon what "best" is. The issues become
even more heated once you add concerns over excessive bandwidth usage and splatter.
The characteristics/capabilities of the IC-746 allow this FAQ to take a neutral position in the
debate.
Stock, the IC-746 has a SSB bandwidth of about 2.4 Khz. That bandwidth can be widened to
as much as 3.4 Khz without deleterious effects (the FAQ describes how elsewhere). Pushing
beyond that point requires more effort than most people are willing to invest.
A lot of "Hi-Fi" activity occurs on or about 14.178 Mhz. There is also an active group of
hams at:
http://groups.yahoo.com/group/hfssbaudio/
8.11 How does one improve the fidelity of a received signal?
Here is a checklist of several possible actions (not in any particular order).
• Assure precise tuning
• Use a high quality external speaker or headphones
• Try to run without pre-amps or with attenuator
• Reduce the RF gain (increase AF gain to compensate)
• Set TPBT to widest bandwidth
• Use wider IF filters
• Lower level of NR (counterclockwise - to the left)
• Turn off NR
• Turn off ANF
• Turn off NB
• Set AGC to SLOW
• Be sure input power is greater than or equal to 13.5 Vdc
• Use an external AF amp via the ACC ports.
• Equalize the AF output.
Page 94 of 113
2003-02-08
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