Mesonet Communications

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MesonetCommunications

• Rafael Mahecha
• Technical Assistant
• Jackson State University
• Meteorology Program
• 10-29-02

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Importance of communications ???

• Remote locations
• access to/from
• Efficient data transfers
• tons of data to deal with
• Products dissemination
• Web, ftp, etc.
• Help good quality control
• Network errors, gaps to fill in, late data, etc.

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Communication Systems Kevin Rhodes (Campbell
Scientific, Inc), at the 2002 Mesonet Meeting,
Oklahoma City, OK

• Evaluate pros cons
• Available power supply, phone proximity, of
  infrastructure, size of network needed
• E.g., phone Vs. satellite Vs. radio
• Phone high , land obstacles, etc.
• Satellite not a 2-way communication, high ,
  etc.
• Radio needs many repeaters, interference, etc.

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Communication Systemsthe solution??? mix
match!

• Satellites
• VHF
• No geographic boundaries
• High initial cost
• Small data throughput
• Depends on someone elses infrastructure

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Communication Systems

• Meteor Burst
• VHF
• Range 1000 miles
• Good data throughput
• Moderate to high initial cost
• Depends on someone elses infrastructure

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Communication Systemscontinued

• Cellular Analog (AMPS)
• 800-900 MHz
• Range limited providers coverage area
• Low throughput
• Monthly bills (yearly contract)
• Diminishing coverage (going to digital cellular)

Cellular South coverage
T-Mobil/VoiceStream Coverage
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Communication Systemscontinued

• Cellular Digital (CDPD, GSM, GPRS)
• 800-900 MHz, 1800MHz
• Range limited to coverage area
• Good throughput
• Monthly bill (yearly contract)
• Not all networks are digital

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Communication Systemscontinued

• UHF VHF
• 50-600 MHz
• Range depends on power of the station
• Good throughput
• Dedicated bandwidth
• Need to get license

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Communication Systemscontinued

• Spread Spectrum Transceivers
• 900-2400MHz
• Range 20 miles
• Good throughput
• No interference
• Broadband (802.11)
• 2.4GHz
• Low range
• Throughput T1 line

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The Oklahoma Example

• OLETS (Oklahoma Law Enforcement
  Telecommunications Systems)
• Two-way radio system

Borrowed from Ronald L. Elliott Biosystems
Agricultural Engineering Dept. Oklahoma State
University
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The Oklahoma Example (continued)

• 115 Mesonet stations
• at least one in each of Oklahomas 77 counties
• average station spacing approx. 30 km (42
  USDA-ARS Micronet stations (reduced set of
  sensors)
• research watershed near Chickasha
• average station spacing approx. 5 km)

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The Oklahoma Example (continued)

• Avg. station transmits 35kb of compressed data
• 1.15 million observations per day
• More than 150 unique web-based products
• 63,000 files per day
• 1,500 web accounts
• 33 million web hits in 2001