[Elecraft] KSB2 Transmit Audio BFO Optimization

[Eric Swartz WA6HHQ - Elecraft]

you wrote:
 > Am Presently using the k2 proset but my audio reports are less than
 > flattering ..John K1GUN

Hi John,

If are getting poor audio reports with the Proset-K2 this indicates that your 
transmit BFO settings (BF1t) for both USB and LSB are not optimally adjusted. 
The default BF1t settings in the KSB2 manual are just starting points and BF1t 
  should be adjusted for best transmit audio for both USB and LSB. Shifting 
BF1t will move your transmit passband up or down, allowing you to emphasize 
your natural voice frequency characteristics. +/- 100 to 200 Hz in these 
settings can make a huge difference in your transmit audio quality.

This procedure is detailed in the last part of the KSB2 manual and I've pasted 
the text below:.
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SSB Transmit BFO Optimization (Important)

When you transmit using SSB mode, the fixed filter on the SSB adapter is 
always used (OP1). The way your voice sounds to other stations depends on the 
BFO settings for this filter (i.e., BF1 in CAL FIL). Table 3 provides BF1 
values for LSB and USB based on the measured crystal filter frequency (from 
page 10). However, you may have to experiment with these settings, adjusting 
them slightly to obtain best voice quality. You can use another ham-band 
receiver, or ask a nearby station listen to your signal as you vary BF1. Use 
CAL FIL, moving the BFO as much as +/- 200 Hz from the frequencies shown in 
Table 3. Start with lower sideband, then upper. Moving the BFO too close to 
the filter will worsen carrier rejection, so be sure to re-check carrier 
amplitude whenever you change the BFO setting.

Note: The BFO settings for LSB and USB are swapped on 15, 12 and 10 meters due 
to the K2's frequency mixing scheme. If you use 17 m or below for making BFO 
changes, the following rules apply: LSB: moving the LSB BFO lower in frequency 
will raise the voice pitch and improve carrier rejection. USB: moving the USB 
BFO higher in frequency will raise the voice pitch and improve carrier rejection.
---

73, Eric   WA6HHQ
Elecraft