What creates intermodulation interference between two repeaters in close proximity?
The output signals cause feedback in the final amplifier of one or both transmitters
The output signals mix in the final amplifier of one or both transmitters✓Correct answer
The input frequencies are harmonically related
The output frequencies are harmonically related
Explanation
Energy radiated by one repeater is coupled into the output stage of the other, where the two signals combine in that stage's nonlinearity and the resulting products are radiated by the antenna. The mechanism does not require the frequencies to be harmonically related, and it is mixing rather than feedback.