Frequency filter



A frequency filter was a machine that allowed one to block out certain unwanted radio frequencies.

Doctor Curum and Colonel Wilcox used a frequency filter to block the microwave miniaturizing beams that were broadcast on the radio and television. This allowed them to listen to the radio without getting shrunk.

While listening, they were able to hear a message from Superman that was sent in code, a secret code only the Justice League knew, so they called in Green Arrow to come and listen to the message so as to decode it for them.

External Link

 * Frequency filter at Wikipedia