What is Radar Note?

Umm, new person here… I'm sure it's explained somewhere else on this site, but I don't have time to search for the answer. Please help

Thanks
Amy
K-W

N/M, I think i figured it out for myself… r-a-d-a-r is spell-able backwards, such as a serial number that is 0123210 etc? If i had just taken the time to think about it, and this time i looked a little closer to the #'s u guyz were talking about and realized the pattern…

You got it cdnprincess….