Meaning
Power analysis determines the total allowable loss between a transmitter and receiver to maintain a functional long range data connection. A sub-ghz link budget combines factors like transmit power, antenna gains and the sensitivity of the receiving chip at specific low frequencies. It informs the decision on whether to use specific repeaters or high gain external antennas to achieve the target range.
Power Floor
Minimum signal requirements at the module input set the limit for how far the device can effectively move from the gateway. In a sub-ghz link budget, the noise floor of the environment is subtracted from the signal strength to find the available margin. High sensitivity receivers allow for budgets exceeding one hundred and forty decibels.
Fade Margin
Reserve power levels are built into the design to account for temporary signal blockage or atmospheric changes. When constructing a sub-ghz link budget, engineers include ten to twenty decibels of extra capacity to handle environmental variance. This prevents data loss when someone moves a piece of furniture or weather shifts occur.
Gain Allocation
Strategic placement of directional antennas increases the signal reach without exceeding legal transmission limits. Every component in the chain must be listed in the sub-ghz link budget to identify bottlenecks. This document is the primary reference for estimating connectivity reliability.
