So close

[wa2ise]

Originally Posted by ctc17

3.58 trap? You mean 4.5 trap?

Before you go twisting coils verify its not something in the house interfering with the set. printers, these new electronic ballasts etc can cause that.

Outside interference would create random patterns, but the sound carrier beating with the chroma subcarrier will produce the regular checkerboard beat pattern in the picture. Also you'll see more of it in parts of the picture that would have highly saturated color on a color TV set. The chroma subcarrier frequency was selected to be 227 1/2 cycles per line, and the sound carrier is 286 cycles per line. You should also see some variation of the beat pattern when the sound becomes active, vs periods of silence. So adjusting a sound carrier trap should help. This trap may also serve as the sound IF takeoff to feed the sound IF. If so, setting it right should also improve the sound.