T1B

Bands, modes and power limits

Where Technicians may use voice, CW and digital modes, how to find a band from a frequency, and the power limits.

12 pool questions1 on the exam

Syllabus: Frequency allocations; Emission modes; Spectrum sharing; Transmissions near band edges; Contacting the International Space Station; Power output

Know where 6 m and 2 m sit

Bands in order, not to scale. Frequencies in MHz.

Band names are roughly 300 ÷ frequency, so 146.52 MHz is about 2 m. Learn the edges: 6 m is 50 to 54 MHz, 2 m is 144 to 148 MHz. 49.00 MHz is just below 6 m and in no amateur band.

Any Technician or higher can contact the ISS on VHF. No General license, no NASA approval.

Memory hook6 m: 50 to 54. 2 m: 144 to 148.

On HF, voice is 10 m only: 28.300 to 28.500

MHz. Not drawn above 28.6 MHz.

Technician voice privileges on HF are only on 10 m, from 28.300 to 28.500 MHz. Below 28.300 is CW and digital.

RememberHF voice: 10 m only, 28.300 to 28.500 MHz.

Voice and digital are everywhere above 50 MHz, except the CW slice

MHz. Segments exaggerated: the CW-only slice is only 100 kHz wide.

Digital modes such as FT8 are allowed on 10, 6 and 2 m. SSB is allowed in at least part of every band above 50 MHz. The only CW-only slices are the bottom 100 kHz of 6 m and 2 m.

Memory hookCW only: 50.0 to 50.1 and 144.0 to 144.1.

Share the band, and stay off the edge

Secondary means you share, and the other user comes first.

Stay a little inside the edge.

A signal is not a thin line. Sidebands, display error and drift can push it past a limit, so set your frequency a little inside the edge.

RememberSecondary: yield. Band edge: leave margin.

Power limits: 200 W on HF, 1500 W above 30 MHz

PEP (peak envelope power) = the power at the peaks of your signal. Bars to scale.

Memory hookHF is the tight limit: 200 W. VHF and up: 1500 W.

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Compendium articles on the ideas in this lesson, beyond what the exam asks.

Check what stuck

Practise the 12 pool questions for this group. Answers are shuffled, and every one comes with a one-line "why".

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