The useful answer: Amp-hour capacity describes charge: one amp-hour is one ampere supplied for one hour under stated test conditions. It does not by itself tell you usable station energy or runtime.
What changes in real operation
Battery voltage, discharge rate, temperature, age, chemistry, cutoff voltage, and allowable depth of discharge all change what the radio can actually use.
The shortcut that causes trouble
Multiplying the label’s amp-hours by an optimistic receive current misses transmit peaks and can drive lead-acid batteries far deeper than intended.
Put it into practice
Convert nominal capacity to watt-hours, apply a chemistry-appropriate usable fraction, build a realistic receive/transmit duty cycle, then leave reserve for cold, aging, and unexpected operating time.
Practical boundary
Use current equipment instructions, battery and controller limits, measurement references, operating rules, and observed propagation. Planning values and propagation labels are not guarantees.
