If someone tells you that signals from your hand-held transceiver are interfering with other signals on a frequency near yours, what could be the cause?

If your hand-held transceiver is causing interference on nearby frequencies, it is likely transmitting spurious emissions. Spurious emissions are unwanted RF energy generated by the transmitter circuitry outside of the intended channel bandwidth. These unwanted emissions can take the form of broad transmitter noise, parasitic oscillations, or intermodulation products. When a radio generates these extra signals, they spill over and disrupt nearby communications, even if your main signal is on the correct frequency. While reducing output power might temporarily reduce the range of the interference, it does not fix the underlying technical defect. A properly functioning radio should have sufficient filtering to prevent interference to nearby frequencies at any legal power setting.