You are completely right. Now that I'm reading it again they are repeating "radio" a lot of times and there are a ton of clues that this is radio frequency, but

You are completely right. Now that I'm reading it again they are repeating "radio" a lot of times and there are a ton of clues that this is radio frequency, but the picture of the device on the yellow peppers just triggered "oh they are measuring the light spectrum of yellow peppers". Sorry for the confusion.