When using the Volume + button on the current Run page's CAT controls, one can never achieve max volume. As well, if one uses the Volume +/- buttons, and then tweaks the AF knob on the radio, there's a big jump in volume, particularly at higher volume settings.
This is due to a clamping and lack of scaling on the Elecraft end. I've reported the following bug to them:
Subject: AG CAT command does not scale audio gain like physical AF knob
Radio: KX2 (likely also affects KX3)
Serial Num: 03338
FW 03.02
Summary:
The AG (AF Gain) CAT command sets internal audio gain to the raw command value
rather than scaling it to match the physical AF knob behavior. This limits
CAT-controlled volume to approximately 25% of the available audio gain range.
Expected Behavior:
AG045; should produce the same audio output level as turning the physical AF
knob to display position 45.
Actual Behavior:
AG045; produces significantly lower audio output than the physical AF knob at
display position 45. The physical knob sounds approximately 4× louder at the
same display value.
Reproduction Steps:
1. Connect to KX2 via serial CAT interface
2. Send: AG045;
3. Observe display shows "AF 45" and note the audio level
4. Manually turn AF knob slightly (e.g., down to 44, then back to 45)
5. Observe display still shows "AF 45" but audio is now significantly louder!
Analysis:
The physical AF knob appears to scale display values 0-60 to internal gain
values 0-255 (approximately 4.25:1 ratio). The AG command appears to set the
internal gain directly to the command value without scaling, effectively
limiting CAT control to internal gain values 0-60 out of 0-255.
Impact:
Remote/CAT control of audio gain cannot exceed approximately 25% of the
physical knob's range. AG060; (maximum accepted value) produces audio
equivalent to the physical knob at roughly position 15. This significantly
impacts our work on SOTAcat.
Suggested Fix:
The AG command should scale input values to match physical knob behavior:
- internal_gain = AG_value × 255 / 60
Alternatively, if AG intentionally uses raw internal values, the command
should accept 000-255 as documented in the Programmer's Reference, rather than
being limited to 000-060.
When using the Volume + button on the current Run page's CAT controls, one can never achieve max volume. As well, if one uses the Volume +/- buttons, and then tweaks the AF knob on the radio, there's a big jump in volume, particularly at higher volume settings.
This is due to a clamping and lack of scaling on the Elecraft end. I've reported the following bug to them: