Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-006-003
How can intermodulation interference between two repeater transmitters in close proximity often be reduced or eliminated?
- A By installing a high-pass filter in the antenna transmission line
- B By using a Class
- C By installing a terminated circulator or ferrite isolator in the transmission line the transmitter and duplexer
- D By installing a low-pass filter in the antenna transmission line
Correct answer: C — By installing a terminated circulator or ferrite isolator in the transmission line the transmitter and duplexer. From the official ISED question bank, verified word for word.
Why
When two powerful repeaters sit close together, one transmitter's signal can leak back into the other, creating unwanted mixing products called intermodulation. The full explanation — and one for every question — is in Pro.
Practise this section
Transmitters, modulation and processing: AM, FM, SSB, keying, speech processing, and the numbers behind occupied bandwidth.