The Basic lessons · Interference and suppression · B-008-001

Understanding and Solving Receiver Overload

Learn why strong nearby signals can overwhelm a radio receiver and how to distinguish this from other types of interference. Discover the specific filters and steps needed to restore clear reception.

This lesson is free to read; the rest are part of SignalPrep Pro. The subsection's 11 exam questions are free to practise: practise B-008-001.

What this subsection asks

• What is the cause of receiver overload?
• What is one way to tell if your HF transmitter causes front-end overload interference to a neighbour's receiver?
• If a neighbour reports television interference whenever you transmit, no matter what band you use, what is probably the cause of the interference?
• What type of filter should be connected to a TV receiver as the first step in trying to prevent receiver overload from an amateur radio HF transmission?
• During a club Field Day outing, reception on the 20-metre SSB station is compromised every time the 20-metre CW station is on the air. What might cause such interference?
• The signals from two commercial transmitters combine outside your receiver to produce noise on a desired frequency. What type of interference is this?
• You have connected your hand-held VHF transceiver to an outside gain antenna. You now hear a mixture of signals together with different modulation on your desired frequency. What is the nature of this interference?
• Two or more strong signals mix in your receiver to produce interference on a desired frequency. What is this called?
• Two mobile stations are communicating through a repeater. As they arrive in close proximity to each other, they begin to have difficulty communicating. What is the most likely cause?
• A television receiver suffers interference on channel 5 (76 MHz - 82 MHz) only when you transmit on 14 MHz. From your home you see the tower of a commercial FM station known to broadcast on 92.5 MHz. Which of these solutions would you try first?
• You are experiencing interference in your VHF receiver. You have determined that signals from two nearby transmitters are mixing in your receiver to cause the interference. What device can you install to reduce the interference?