Experimental characterisation of in‐to‐out‐body path loss at 433 MHz in dairy cows

Abstract

In this Letter, for the first time, the in-to-out-body path loss between an antenna placed inside the cows' rumen and a distant gateway was characterised at 433 MHz. Measurements were conducted on seven different fistulated cows using a signal generator and a spectrum analyser. Subsequent measurement of the antenna in free space was used to quantify the path loss increase due to the cow body. Results have shown an increase of the path loss by 45.5 dB on average (all cows), with a variation between 39.7 and 51.1 dB. Also, the measured path loss values as a function of the transmitter-receiver distance in a dairy barn were well fitted by a log-normal path loss model. The obtained models were used to calculate the range of a LoRa (Long range) based network. Ranges up to 100 m were obtained depending on the used transmit power and bit rate.