signal fire
烽 centers on a fire used as a visible signal over distance: a signal fire or beacon.
烽 combines 火 (fire) with 夆, which likely contributes the sound and may relate to a raised or prominent place, together suggesting a fire signal raised high.
The left side is fire 火, and the right side 夆 looks like a tall structure with a pointed top. Picture a fire burning on a high tower as a signal.
For ホウ, imagine a signal fire blazing on a high peak, and someone shouts 'Ho!' to alert the village: Ho -> ホウ.