--- In ultralightdx@..., Rick Robinson <w4dst@...> wrote:
In addition to the soft mute problem, the G8 and PL-310 I have
both exhibit an annoying "pumping" of the AGC which the '380 does not
have. Someone has referred to this as "chuffing" but whatever you call
it, it is so annoying that I consider the G8 and '310 almost unusable
for my MW DXing. This is due to parameters that are programmed into
whatever microprocessor chip is controlling the Si4734. By studying the
Silicon Labs document AN332 "Si47XX Programming Guide", these settings
appear to be for AM_AGC_ATTACK_RATE and AM_AGC_RELEASE_RATE. Scott
Willingham, please correct me if I'm wrong.
I am not sure what causes the AGC difference you are hearing, but it can't be the parameters you mention as those only apply to the Si474x versions of the part (automotive grades). I have observed that Tecsun sets the parameter AM_AUTOMATIC_VOLUME_CONTROL_MAX_GAIN in the PL-380 to higher values than recommended in the program guides. Sometimes I like to reduce that value. I haven't examined the settings in a PL-310 or G8, so I don't know whether they do the same.