I know no one cares to see my graphs... But I posted another one anyways. Thank you for this little nugget! I suspected the PL filter as well....
Threw those resistors on tonight, and while the difference in response measured is not that great, the difference to the ear is huge! This really cleaned up the audio on my box on the bench. Measuring a pure sine wave will probably not show the real effects the ringing has on speech and other complex waveforms, likely validating my observation that the speech is significantly cleaned up. Thanks again for the great experience shared with the group! Tom W9SRV Jeff is right on the nose here.... I have swept the MICOR and MOTRAC PL filters and there is a defined peak around 400 Hz. It is likely caused by the self resonance of the 6 Henry chokes and associated support components which create the tuned network used in the filter. This can be tamed down (filter made to be flatter in response) to some degree by placing a 220K resistor across the choke(s). See Here: http://www.repeater-builder.com/rbtip/plf.html Kevin Custer
