Question T4B10
From subelement T4 - T4B
Which of the following receiver filter bandwidths provides the best signal-to-noise ratio for SSB reception?
Why is this correct?
2400 Hz provides the best signal-to-noise ratio for SSB reception because it matches SSB's natural bandwidth of approximately 3 kHz. A 500 Hz filter is too narrow and cuts off voice frequencies, making speech sound muffled. 1000 Hz is still too narrow for full voice intelligibility. 5000 Hz is unnecessarily wide, allowing extra noise without improving the signal, degrading the signal-to-noise ratio.
Memory tip
The optimal filter bandwidth should match the signal's natural bandwidth. Too narrow cuts signal content; too wide adds noise without benefit. This 'Goldilocks principle' applies across all modulation modes—use bandwidth that captures the essential signal without excess.
Learn more
In practical operation, receiver bandwidth controls are critical for weak signal work. SSB's approximately 3 kHz signal spectrum contains all essential voice frequencies from roughly 300-3000 Hz. Using a 2400 Hz filter captures these frequencies while rejecting adjacent channel interference and atmospheric noise. This becomes especially important during contest weekends or band openings when stations are closely spaced, and proper filtering separates signals that would otherwise interfere.
Think about it
Why do you think using a filter that's significantly wider than the signal's bandwidth actually makes reception worse instead of better?