ALC Level
Hi,
I should probably ask this on a VARA forum (if one exists), but let me try here first.
In digital modes like FT8, JS8Call, and FreeDV, it is generally recommended to set the audio level to the radio so that the ALC meter does not move.
For VARA, however, it recommends allowing the ALC to reach about 1/3 of full scale.
Where does this difference come from? I'd love to understand the technical reasons behind it.
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I believe your "recommendation" is based on the audio level screen in VARA. This is an oversimplification that has caused many operators to have suboptimal performance. I truly wish that graphic was removed.
At low data rates (SL4 and lower,) FSK is used, which is very tolerant of ALC and you can actually use moderate ALC to increase power to some degree. As soon as you move into any of the higher levels, ALC instantly becomes detrimental and should be avoided.
Matt
AL0R