Re: Measuring PL-380 Soft-Mute


sdwillingham
 

An update:

My PL-380 (2009.9 ver 1) now has an added USB interface. With this, I can read back the Si4734 soft-mute parameters as Tecsun has set them up. As previously measured, the software verifies that the maximum soft-mute attenuation is 6 dB. The parameters reveal some added details. The soft-mute threshold is actually 3 dB and the slope is 2 dB/dB. This means that there is no soft-mute effect at all for SNR readings of 3 or more. Below 3 dB SNR, the audio is attenuated 2 dB for every 2 dB decrease in SNR, up to a maximum of 6 dB when SNR reaches its minimum reported value of 0 dB.

-Scott-

--- In ultralightdx@..., "sdwillingham" <sdwillingham@...> wrote:

The conclusion is, PL-380 2009.9 ver 1 radios have about 6 dB
soft-mute. This probably also means that the soft-mute
threshold is 6 dB, but that is not certain. We can also
conclude that Tecsun is setting this deliberately, since it does
not match with the Si4734 defaults (neither firmware 2.0 or
4.0). Perhaps one of you with a 'new' model can test if the
settings have been changed.

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