It is important that amateur radio operators be aware of spurious radio signals that can potentially interfere with other radios. It is especially important that spurious radio signals not interfere with emergency communications. And as Hams we have a responsibility to not interfere with other Hams during rag chew or other chat nets. Furthermore, Part 97 of Title 47 of the Federal Communications Commission (FCC) rules prohibit spurious Radio Frequency (RF) signals.
It is the responsibility of radio engineers to design radios with the proper filters to block or suppress transmitted spurious emissions. Many Ham radio manufactures do this with 100% of their radios. Unfortunately some low-end manufacturers do not. Our Amateur Radio Relay League (ARRL) labs test radios for spurious emissions. In addition they attend Ham feats and test radios of attendees that volunteer to have their radios tested.
Please read their published results before purchasing a radio so that you buy a radio that is in compliance with FCC rules on spurious signals.
A Cautionary Tale for New Hams and Other Prospective Buyers about Handheld Transceivers