A method for multiple access, the method for multiple access comprising: generating a random number in a radio transmitter with reference to a signal from a first oscillator that is associated with the radio transmitter and another signal from a second oscillator that is associated with a moisture sensor; transmitting the random number from the radio transmitter to a radio receiver; initializing a first predetermined pseudo-random process with the random number in the radio transmitter; identifying with the radio transmitter a plurality of transmission times for transmission of a plurality of data messages from the radio transmitter, to each transmission time in the plurality of transmission times being identified with reference to a predetermined time period between transmitting each data message in the plurality of data messages that is modified with reference to one pseudo-random time offset from the first predetermined pseudo-random process, and a time of transmission of a previous data message in the plurality of data messages; transmitting each data message in the plurality of data messages from the radio transmitter at a corresponding transmission time in the plurality of transmission times; receiving the random number from the radio transmitter with the radio receiver; initializing a second predetermined pseudo-random process with the random number in the radio receiver; identifying with the radio receiver the plurality of transmission times from the radio transmitter, each transmission time in the plurality of transmission times being_identified with reference to the predetermined time period between transmitting each data message in the plurality of data messages modified with reference to one pseudo-random time offset from the second predetermined pseudo-random process, and the another time of transmission of a previous data message in the plurality of data messages; operating the radio receiver at a first electrical power level for a first plurality of time periods that correspond to time periods between the plurality of transmission times for the radio transmitter; and operating the radio receiver at a second electrical power level for a second plurality of time periods corresponding to the plurality of transmission times for the radio transmitter to enable the radio receiver to receive the plurality of data messages transmitted by the radio transmitter, the second electrical power level being greater than the first electrical power level. generating a random number in a radio transmitter with reference to a signal from a first oscillator that is associated with the radio transmitter and another signal from a second oscillator that is associated with a moisture sensor; transmitting the random number from the radio transmitter to a radio receiver; initializing a first predetermined pseudo-random process with the random number in the radio transmitter; identifying with the radio transmitter a plurality of transmission times for transmission of a plurality of data messages from the radio transmitter, to each transmission time in the plurality of transmission times being identified with reference to a predetermined time period between transmitting each data message in the plurality of data messages that is modified with reference to one pseudo-random time offset from the first predetermined pseudo-random process, and a time of transmission of a previous data message in the plurality of data messages; transmitting each data message in the plurality of data messages from the radio transmitter at a corresponding transmission time in the plurality of transmission times; receiving the random number from the radio transmitter with the radio receiver; initializing a second predetermined pseudo-random process with the random number in the radio receiver; identifying with the radio receiver the plurality of transmission times from the radio transmitter, each transmission time in the plurality of transmission times being_identified with reference to the predetermined time period between transmitting each data message in the plurality of data messages modified with reference to one pseudo-random time offset from the second predetermined pseudo-random process, and the another time of transmission of a previous data message in the plurality of data messages; operating the radio receiver at a first electrical power level for a first plurality of time periods that correspond to time periods between the plurality of transmission times for the radio transmitter; and operating the radio receiver at a second electrical power level for a second plurality of time periods corresponding to the plurality of transmission times for the radio transmitter to enable the radio receiver to receive the plurality of data messages transmitted by the radio transmitter, the second electrical power level being greater than the first electrical power level.