1999 AGN JUN 01 I10 - Laserfiche WebLink

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fr W3) fAletrIMM' POWER CONSUMPTION REPORT METRICOM HIGH SPEED RICOCHET NETWORK RADIOS Power consumption tests were conducted on four Metricom High Speed Ricochet2 Network radios to determine their power consumption in network applications. Power consumption measurements were taken under the following: • Conditions: • Voltage inputs: 120 & 240 VAC • Temperature: 23 C • Radio modes: • Standby/receive 26.02 watts C 120 VAC (26.15 @ 240 VAC) • Transmit 900 MHz 37.0 watts C 120 VAC (36.8 a 240 VAC) • Transmit 2.4 GHz 36.6 watts Q 120 VAC (36.4 @ 240 VAC) Note: Under normal network operation, the network radio will be in the transmit mode between 1-4% of the time depending on traffic (average 2.5%). • Average power consumptions were computed based on an analytical derivation and empirical measurements of the present Ricochet network (note that the results are essentially the same for 120 VAC or 240 VAC): • Transmit duty cycle: 2.5% • Receive mode: 97.5% • Transmit 900 MHz: 75% of transmit • Transmit 2.4 GHz: 25% of transmit 26.02 W x 97.5% + 37.0 W x (2.5% x 0.25%) + 36.6 W x (2.5% x 0.75%) = 26. 28 W • Yearly consumption and costs (based on 10c/kWhr) are projected at: 26.28 W x 8760 hrs/year x $0.1/kWhr = 230.212 kWhrs/year and $23.02/year. To determine the appropriate annual cost at a different per kWh rate, simply substitute the applicable rate for $0.1/kWhr. Mike Cunningham 1/29/99 Director Research & Quality Assurance Metricom, Inc. Power consViper.doc