Question T2A03
From subelement T2 - T2A
What is a common repeater frequency offset in the 70 cm band?
Why is this correct?
A repeater offset is the frequency difference between receive and transmit frequencies. The 70 cm band (420-450 MHz) commonly uses ±5 MHz offsets, while 2 meters uses ±600 kHz. The larger offset in 70 cm accommodates the band's wider frequency range and reduces interference between input and output signals.
Memory tip
Remember band-to-offset patterns: higher frequency bands generally use larger offsets. 2m = 600 kHz, 70cm = 5 MHz. The offset scales with the band's operating frequency range—think proportional spacing for interference prevention.
Learn more
In practical repeater operation, your transceiver automatically applies the correct offset when you program a repeater frequency. However, understanding offsets helps when manually programming radios or troubleshooting access issues. Some repeaters use non-standard offsets due to local frequency coordination requirements. The reverse function lets you monitor the repeater's input frequency to hear stations directly, useful for signal strength checks and determining if communication issues stem from your signal into the repeater versus the repeater's coverage.
Think about it
Why do you think higher frequency bands like 70 cm require larger frequency offsets compared to lower bands like 2 meters?