Bulletin:  SK1020
Vendor:    Kantronics
Subject:   KAM HF Performance Improvement

The graph below shows the typical audio passband shape of most HF
transceivers. The default MARK/SPACE tones for the KAM [4.0 firmware] is
1600/1800 hz. I found the out-of-the-box performance on HF pkt to be
marginal. It worked. But compared to my PK-232, not very well.

I then changed the MARK/SPACE tones to 2110/2310 (same as PK-232) and
instantly the performance improved with fewer retries and better thruput.
It would "appear" that the GAIN and overall performance was limited with
the original setting due to being on the side of the passband versus
being in the middle.

                1.0 1.5  2.0  2.5 3.0 KHz
              ---|---|----|----|---|---

                         *** <- SHOULD BE HERE?
              DEFAULT   *****
              KAM      *******
              HERE -> *********
                     ***********
                    *************

WD1V/John/Manchester