| 455 / | HD | TELECOMMUNICATIONS |
| 130 | DF | RECEIVER OR ANALOG MODULATED SIGNAL FREQUENCY CONVERTER {24} |
| 269 | DF | .~ With wave collector (e.g., antenna) {4} |
| 272 | DF | .~.~ Plural separate collectors {5} |
| 277.1 | ![]() | .~.~.~ Selectively or alternately connected to receiver {1} |
| 277.2 | DF | .~.~.~.~> By signal quality (e.g., noise) |