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Calculate distance, range, power, fade margin for a 2.4GHz wireless link.

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Winnipeg, Manitoba - Canada
 

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The distance that a signal can travel, given that it has proper line-of-sight, is dependent on the strength of the signal minus the free space path loss and the receiver sensitivity.

Formula:

    signal rec = transmit EIRP - free space loss + rec antenna - rec cable loss

    where free space loss = 32.4 + (20 * (log10 freq)) + (20 * (log10 distance))

Added to this we would want to add a fade margin to compensate for varying conditions and improve reliability.

The following should provide a rough estimate for determining the signal strength over a certain distance.

Transmitter power output = (dBm)

Transmitter cable attenuation = (dB)   (eg 6.8dB per 100' of LMR400)

Transmitter antenna gain = (dBi)

Receiver sensitivity = (dBm)

Receiver cable attenuation = (dB)

Receiver antenna gain = (dBi)

Link Distance = (km)

(Frequency = 2.4GHz)

Received signal strength = -58.8 (dBm)

Fade Margin = 26.1 (db)

Reliability = EXCELLENT

If different radios are used at either end, it is important to consider that the signal needs to work well in both directions. Use the weaker of the two directions when designing your link.