Pulsar processing equipment causes problems. Malfunctioning maser dissociator produced interference. Unknown line at 321.4 affects mostly stations W7,8,9. Vehicle transmitters cause problems, even on standby. CB scanner causes problems.
Apples radiate, especially their printers.
Not clear what the balance of effort between them should be. On this antenna, IF B is much worse than others, probably due to ideosyncrasy of the standing wave, because the properties of the standing wave are pretty well independent of band, and compatible with a standing wave in the waveguide.