For a amateur radio course for FRO covering radio interferance and prevention

1. Radio Interference

2. Overview What is it? Radio Interference Preventing

3. What is it? Unwanted signals Effect electronic circuits

4. Radio Interference International Electrotechnical Commission 1933 set up International Special Committee on Radio Interference EU EMC Directive (89/336/EC) Immunity Emissions

5. Radio Interference Types Narrow band TX equipment Broad band Power lines Motors Computers and TV Antenna Outside of antenna cable Unbalanced Power supplies

6. Radio Interference Sources Transmitting equipment Harmonics Wrong frequency Faulty electronic equipment Sun Auroras Splatter

7. RX interference sources Clipping Square wave Harmonics Clipping from Power Microphone

8. Preventing Filter Don’t over drive the system Use baluns RF choke Faraday Cage Cables Electric Earth

9. Preventing Baluns Matching between balanced and unbalanced lines Conver between 300/450 W lines and 75 W coax

10. Preventing Baluns Wound around a iron core

11. Preventing RF choke inductor

12. Preventing Faraday Cage Metal cage or mesh Can block radio waves Small gapes depending on wavelength

13. Preventing Cables Twisted pair Cancelling out Coax Inner conductor Outer “shielding” conductor

14. Preventing Electrical earth